linux/drivers/serial/atmel_serial.c

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/*
* linux/drivers/char/atmel_serial.c
*
* Driver for Atmel AT91 / AT32 Serial ports
* Copyright (C) 2003 Rick Bronson
*
* Based on drivers/char/serial_sa1100.c, by Deep Blue Solutions Ltd.
* Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
*
* DMA support added by Chip Coldwell.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include <linux/module.h>
#include <linux/tty.h>
#include <linux/ioport.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/serial.h>
#include <linux/clk.h>
#include <linux/console.h>
#include <linux/sysrq.h>
#include <linux/tty_flip.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/atmel_pdc.h>
#include <linux/atmel_serial.h>
#include <asm/io.h>
#include <asm/mach/serial_at91.h>
#include <mach/board.h>
#ifdef CONFIG_ARM
#include <mach/cpu.h>
#include <mach/gpio.h>
#endif
#define PDC_BUFFER_SIZE 512
/* Revisit: We should calculate this based on the actual port settings */
#define PDC_RX_TIMEOUT (3 * 10) /* 3 bytes */
#if defined(CONFIG_SERIAL_ATMEL_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#endif
#include <linux/serial_core.h>
#ifdef CONFIG_SERIAL_ATMEL_TTYAT
/* Use device name ttyAT, major 204 and minor 154-169. This is necessary if we
* should coexist with the 8250 driver, such as if we have an external 16C550
* UART. */
#define SERIAL_ATMEL_MAJOR 204
#define MINOR_START 154
#define ATMEL_DEVICENAME "ttyAT"
#else
/* Use device name ttyS, major 4, minor 64-68. This is the usual serial port
* name, but it is legally reserved for the 8250 driver. */
#define SERIAL_ATMEL_MAJOR TTY_MAJOR
#define MINOR_START 64
#define ATMEL_DEVICENAME "ttyS"
#endif
#define ATMEL_ISR_PASS_LIMIT 256
/* UART registers. CR is write-only, hence no GET macro */
#define UART_PUT_CR(port,v) __raw_writel(v, (port)->membase + ATMEL_US_CR)
#define UART_GET_MR(port) __raw_readl((port)->membase + ATMEL_US_MR)
#define UART_PUT_MR(port,v) __raw_writel(v, (port)->membase + ATMEL_US_MR)
#define UART_PUT_IER(port,v) __raw_writel(v, (port)->membase + ATMEL_US_IER)
#define UART_PUT_IDR(port,v) __raw_writel(v, (port)->membase + ATMEL_US_IDR)
#define UART_GET_IMR(port) __raw_readl((port)->membase + ATMEL_US_IMR)
#define UART_GET_CSR(port) __raw_readl((port)->membase + ATMEL_US_CSR)
#define UART_GET_CHAR(port) __raw_readl((port)->membase + ATMEL_US_RHR)
#define UART_PUT_CHAR(port,v) __raw_writel(v, (port)->membase + ATMEL_US_THR)
#define UART_GET_BRGR(port) __raw_readl((port)->membase + ATMEL_US_BRGR)
#define UART_PUT_BRGR(port,v) __raw_writel(v, (port)->membase + ATMEL_US_BRGR)
#define UART_PUT_RTOR(port,v) __raw_writel(v, (port)->membase + ATMEL_US_RTOR)
/* PDC registers */
#define UART_PUT_PTCR(port,v) __raw_writel(v, (port)->membase + ATMEL_PDC_PTCR)
#define UART_GET_PTSR(port) __raw_readl((port)->membase + ATMEL_PDC_PTSR)
#define UART_PUT_RPR(port,v) __raw_writel(v, (port)->membase + ATMEL_PDC_RPR)
#define UART_GET_RPR(port) __raw_readl((port)->membase + ATMEL_PDC_RPR)
#define UART_PUT_RCR(port,v) __raw_writel(v, (port)->membase + ATMEL_PDC_RCR)
#define UART_PUT_RNPR(port,v) __raw_writel(v, (port)->membase + ATMEL_PDC_RNPR)
#define UART_PUT_RNCR(port,v) __raw_writel(v, (port)->membase + ATMEL_PDC_RNCR)
#define UART_PUT_TPR(port,v) __raw_writel(v, (port)->membase + ATMEL_PDC_TPR)
#define UART_PUT_TCR(port,v) __raw_writel(v, (port)->membase + ATMEL_PDC_TCR)
#define UART_GET_TCR(port) __raw_readl((port)->membase + ATMEL_PDC_TCR)
static int (*atmel_open_hook)(struct uart_port *);
static void (*atmel_close_hook)(struct uart_port *);
struct atmel_dma_buffer {
unsigned char *buf;
dma_addr_t dma_addr;
unsigned int dma_size;
unsigned int ofs;
};
struct atmel_uart_char {
u16 status;
u16 ch;
};
#define ATMEL_SERIAL_RINGSIZE 1024
/*
* We wrap our port structure around the generic uart_port.
*/
struct atmel_uart_port {
struct uart_port uart; /* uart */
struct clk *clk; /* uart clock */
int may_wakeup; /* cached value of device_may_wakeup for times we need to disable it */
u32 backup_imr; /* IMR saved during suspend */
int break_active; /* break being received */
short use_dma_rx; /* enable PDC receiver */
short pdc_rx_idx; /* current PDC RX buffer */
struct atmel_dma_buffer pdc_rx[2]; /* PDC receier */
short use_dma_tx; /* enable PDC transmitter */
struct atmel_dma_buffer pdc_tx; /* PDC transmitter */
struct tasklet_struct tasklet;
unsigned int irq_status;
unsigned int irq_status_prev;
struct circ_buf rx_ring;
};
static struct atmel_uart_port atmel_ports[ATMEL_MAX_UART];
#ifdef SUPPORT_SYSRQ
static struct console atmel_console;
#endif
static inline struct atmel_uart_port *
to_atmel_uart_port(struct uart_port *uart)
{
return container_of(uart, struct atmel_uart_port, uart);
}
#ifdef CONFIG_SERIAL_ATMEL_PDC
static bool atmel_use_dma_rx(struct uart_port *port)
{
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
return atmel_port->use_dma_rx;
}
static bool atmel_use_dma_tx(struct uart_port *port)
{
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
return atmel_port->use_dma_tx;
}
#else
static bool atmel_use_dma_rx(struct uart_port *port)
{
return false;
}
static bool atmel_use_dma_tx(struct uart_port *port)
{
return false;
}
#endif
/*
* Return TIOCSER_TEMT when transmitter FIFO and Shift register is empty.
*/
static u_int atmel_tx_empty(struct uart_port *port)
{
return (UART_GET_CSR(port) & ATMEL_US_TXEMPTY) ? TIOCSER_TEMT : 0;
}
/*
* Set state of the modem control output lines
*/
static void atmel_set_mctrl(struct uart_port *port, u_int mctrl)
{
unsigned int control = 0;
unsigned int mode;
#ifdef CONFIG_ARCH_AT91RM9200
if (cpu_is_at91rm9200()) {
/*
* AT91RM9200 Errata #39: RTS0 is not internally connected
* to PA21. We need to drive the pin manually.
*/
if (port->mapbase == AT91RM9200_BASE_US0) {
if (mctrl & TIOCM_RTS)
at91_set_gpio_value(AT91_PIN_PA21, 0);
else
at91_set_gpio_value(AT91_PIN_PA21, 1);
}
}
#endif
if (mctrl & TIOCM_RTS)
control |= ATMEL_US_RTSEN;
else
control |= ATMEL_US_RTSDIS;
if (mctrl & TIOCM_DTR)
control |= ATMEL_US_DTREN;
else
control |= ATMEL_US_DTRDIS;
UART_PUT_CR(port, control);
/* Local loopback mode? */
mode = UART_GET_MR(port) & ~ATMEL_US_CHMODE;
if (mctrl & TIOCM_LOOP)
mode |= ATMEL_US_CHMODE_LOC_LOOP;
else
mode |= ATMEL_US_CHMODE_NORMAL;
UART_PUT_MR(port, mode);
}
/*
* Get state of the modem control input lines
*/
static u_int atmel_get_mctrl(struct uart_port *port)
{
unsigned int status, ret = 0;
status = UART_GET_CSR(port);
/*
* The control signals are active low.
*/
if (!(status & ATMEL_US_DCD))
ret |= TIOCM_CD;
if (!(status & ATMEL_US_CTS))
ret |= TIOCM_CTS;
if (!(status & ATMEL_US_DSR))
ret |= TIOCM_DSR;
if (!(status & ATMEL_US_RI))
ret |= TIOCM_RI;
return ret;
}
/*
* Stop transmitting.
*/
static void atmel_stop_tx(struct uart_port *port)
{
if (atmel_use_dma_tx(port)) {
/* disable PDC transmit */
UART_PUT_PTCR(port, ATMEL_PDC_TXTDIS);
UART_PUT_IDR(port, ATMEL_US_ENDTX | ATMEL_US_TXBUFE);
} else
UART_PUT_IDR(port, ATMEL_US_TXRDY);
}
/*
* Start transmitting.
*/
static void atmel_start_tx(struct uart_port *port)
{
if (atmel_use_dma_tx(port)) {
if (UART_GET_PTSR(port) & ATMEL_PDC_TXTEN)
/* The transmitter is already running. Yes, we
really need this.*/
return;
UART_PUT_IER(port, ATMEL_US_ENDTX | ATMEL_US_TXBUFE);
/* re-enable PDC transmit */
UART_PUT_PTCR(port, ATMEL_PDC_TXTEN);
} else
UART_PUT_IER(port, ATMEL_US_TXRDY);
}
/*
* Stop receiving - port is in process of being closed.
*/
static void atmel_stop_rx(struct uart_port *port)
{
if (atmel_use_dma_rx(port)) {
/* disable PDC receive */
UART_PUT_PTCR(port, ATMEL_PDC_RXTDIS);
UART_PUT_IDR(port, ATMEL_US_ENDRX | ATMEL_US_TIMEOUT);
} else
UART_PUT_IDR(port, ATMEL_US_RXRDY);
}
/*
* Enable modem status interrupts
*/
static void atmel_enable_ms(struct uart_port *port)
{
UART_PUT_IER(port, ATMEL_US_RIIC | ATMEL_US_DSRIC
| ATMEL_US_DCDIC | ATMEL_US_CTSIC);
}
/*
* Control the transmission of a break signal
*/
static void atmel_break_ctl(struct uart_port *port, int break_state)
{
if (break_state != 0)
UART_PUT_CR(port, ATMEL_US_STTBRK); /* start break */
else
UART_PUT_CR(port, ATMEL_US_STPBRK); /* stop break */
}
/*
* Stores the incoming character in the ring buffer
*/
static void
atmel_buffer_rx_char(struct uart_port *port, unsigned int status,
unsigned int ch)
{
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
struct circ_buf *ring = &atmel_port->rx_ring;
struct atmel_uart_char *c;
if (!CIRC_SPACE(ring->head, ring->tail, ATMEL_SERIAL_RINGSIZE))
/* Buffer overflow, ignore char */
return;
c = &((struct atmel_uart_char *)ring->buf)[ring->head];
c->status = status;
c->ch = ch;
/* Make sure the character is stored before we update head. */
smp_wmb();
ring->head = (ring->head + 1) & (ATMEL_SERIAL_RINGSIZE - 1);
}
/*
* Deal with parity, framing and overrun errors.
*/
static void atmel_pdc_rxerr(struct uart_port *port, unsigned int status)
{
/* clear error */
UART_PUT_CR(port, ATMEL_US_RSTSTA);
if (status & ATMEL_US_RXBRK) {
/* ignore side-effect */
status &= ~(ATMEL_US_PARE | ATMEL_US_FRAME);
port->icount.brk++;
}
if (status & ATMEL_US_PARE)
port->icount.parity++;
if (status & ATMEL_US_FRAME)
port->icount.frame++;
if (status & ATMEL_US_OVRE)
port->icount.overrun++;
}
/*
* Characters received (called from interrupt handler)
*/
IRQ: Maintain regs pointer globally rather than passing to IRQ handlers Maintain a per-CPU global "struct pt_regs *" variable which can be used instead of passing regs around manually through all ~1800 interrupt handlers in the Linux kernel. The regs pointer is used in few places, but it potentially costs both stack space and code to pass it around. On the FRV arch, removing the regs parameter from all the genirq function results in a 20% speed up of the IRQ exit path (ie: from leaving timer_interrupt() to leaving do_IRQ()). Where appropriate, an arch may override the generic storage facility and do something different with the variable. On FRV, for instance, the address is maintained in GR28 at all times inside the kernel as part of general exception handling. Having looked over the code, it appears that the parameter may be handed down through up to twenty or so layers of functions. Consider a USB character device attached to a USB hub, attached to a USB controller that posts its interrupts through a cascaded auxiliary interrupt controller. A character device driver may want to pass regs to the sysrq handler through the input layer which adds another few layers of parameter passing. I've build this code with allyesconfig for x86_64 and i386. I've runtested the main part of the code on FRV and i386, though I can't test most of the drivers. I've also done partial conversion for powerpc and MIPS - these at least compile with minimal configurations. This will affect all archs. Mostly the changes should be relatively easy. Take do_IRQ(), store the regs pointer at the beginning, saving the old one: struct pt_regs *old_regs = set_irq_regs(regs); And put the old one back at the end: set_irq_regs(old_regs); Don't pass regs through to generic_handle_irq() or __do_IRQ(). In timer_interrupt(), this sort of change will be necessary: - update_process_times(user_mode(regs)); - profile_tick(CPU_PROFILING, regs); + update_process_times(user_mode(get_irq_regs())); + profile_tick(CPU_PROFILING); I'd like to move update_process_times()'s use of get_irq_regs() into itself, except that i386, alone of the archs, uses something other than user_mode(). Some notes on the interrupt handling in the drivers: (*) input_dev() is now gone entirely. The regs pointer is no longer stored in the input_dev struct. (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does something different depending on whether it's been supplied with a regs pointer or not. (*) Various IRQ handler function pointers have been moved to type irq_handler_t. Signed-Off-By: David Howells <dhowells@redhat.com> (cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
2006-10-05 21:55:46 +08:00
static void atmel_rx_chars(struct uart_port *port)
{
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
unsigned int status, ch;
status = UART_GET_CSR(port);
while (status & ATMEL_US_RXRDY) {
ch = UART_GET_CHAR(port);
/*
* note that the error handling code is
* out of the main execution path
*/
if (unlikely(status & (ATMEL_US_PARE | ATMEL_US_FRAME
| ATMEL_US_OVRE | ATMEL_US_RXBRK)
|| atmel_port->break_active)) {
/* clear error */
UART_PUT_CR(port, ATMEL_US_RSTSTA);
if (status & ATMEL_US_RXBRK
&& !atmel_port->break_active) {
atmel_port->break_active = 1;
UART_PUT_IER(port, ATMEL_US_RXBRK);
} else {
/*
* This is either the end-of-break
* condition or we've received at
* least one character without RXBRK
* being set. In both cases, the next
* RXBRK will indicate start-of-break.
*/
UART_PUT_IDR(port, ATMEL_US_RXBRK);
status &= ~ATMEL_US_RXBRK;
atmel_port->break_active = 0;
}
}
atmel_buffer_rx_char(port, status, ch);
status = UART_GET_CSR(port);
}
tasklet_schedule(&atmel_port->tasklet);
}
/*
* Transmit characters (called from tasklet with TXRDY interrupt
* disabled)
*/
static void atmel_tx_chars(struct uart_port *port)
{
struct circ_buf *xmit = &port->info->xmit;
if (port->x_char && UART_GET_CSR(port) & ATMEL_US_TXRDY) {
UART_PUT_CHAR(port, port->x_char);
port->icount.tx++;
port->x_char = 0;
}
if (uart_circ_empty(xmit) || uart_tx_stopped(port))
return;
while (UART_GET_CSR(port) & ATMEL_US_TXRDY) {
UART_PUT_CHAR(port, xmit->buf[xmit->tail]);
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
port->icount.tx++;
if (uart_circ_empty(xmit))
break;
}
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(port);
if (!uart_circ_empty(xmit))
UART_PUT_IER(port, ATMEL_US_TXRDY);
}
/*
* receive interrupt handler.
*/
static void
atmel_handle_receive(struct uart_port *port, unsigned int pending)
{
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
if (atmel_use_dma_rx(port)) {
/*
* PDC receive. Just schedule the tasklet and let it
* figure out the details.
*
* TODO: We're not handling error flags correctly at
* the moment.
*/
if (pending & (ATMEL_US_ENDRX | ATMEL_US_TIMEOUT)) {
UART_PUT_IDR(port, (ATMEL_US_ENDRX
| ATMEL_US_TIMEOUT));
tasklet_schedule(&atmel_port->tasklet);
}
if (pending & (ATMEL_US_RXBRK | ATMEL_US_OVRE |
ATMEL_US_FRAME | ATMEL_US_PARE))
atmel_pdc_rxerr(port, pending);
}
/* Interrupt receive */
if (pending & ATMEL_US_RXRDY)
atmel_rx_chars(port);
else if (pending & ATMEL_US_RXBRK) {
/*
* End of break detected. If it came along with a
* character, atmel_rx_chars will handle it.
*/
UART_PUT_CR(port, ATMEL_US_RSTSTA);
UART_PUT_IDR(port, ATMEL_US_RXBRK);
atmel_port->break_active = 0;
}
}
/*
* transmit interrupt handler. (Transmit is IRQF_NODELAY safe)
*/
static void
atmel_handle_transmit(struct uart_port *port, unsigned int pending)
{
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
if (atmel_use_dma_tx(port)) {
/* PDC transmit */
if (pending & (ATMEL_US_ENDTX | ATMEL_US_TXBUFE)) {
UART_PUT_IDR(port, ATMEL_US_ENDTX | ATMEL_US_TXBUFE);
tasklet_schedule(&atmel_port->tasklet);
}
} else {
/* Interrupt transmit */
if (pending & ATMEL_US_TXRDY) {
UART_PUT_IDR(port, ATMEL_US_TXRDY);
tasklet_schedule(&atmel_port->tasklet);
}
}
}
/*
* status flags interrupt handler.
*/
static void
atmel_handle_status(struct uart_port *port, unsigned int pending,
unsigned int status)
{
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
if (pending & (ATMEL_US_RIIC | ATMEL_US_DSRIC | ATMEL_US_DCDIC
| ATMEL_US_CTSIC)) {
atmel_port->irq_status = status;
tasklet_schedule(&atmel_port->tasklet);
}
}
/*
* Interrupt handler
*/
IRQ: Maintain regs pointer globally rather than passing to IRQ handlers Maintain a per-CPU global "struct pt_regs *" variable which can be used instead of passing regs around manually through all ~1800 interrupt handlers in the Linux kernel. The regs pointer is used in few places, but it potentially costs both stack space and code to pass it around. On the FRV arch, removing the regs parameter from all the genirq function results in a 20% speed up of the IRQ exit path (ie: from leaving timer_interrupt() to leaving do_IRQ()). Where appropriate, an arch may override the generic storage facility and do something different with the variable. On FRV, for instance, the address is maintained in GR28 at all times inside the kernel as part of general exception handling. Having looked over the code, it appears that the parameter may be handed down through up to twenty or so layers of functions. Consider a USB character device attached to a USB hub, attached to a USB controller that posts its interrupts through a cascaded auxiliary interrupt controller. A character device driver may want to pass regs to the sysrq handler through the input layer which adds another few layers of parameter passing. I've build this code with allyesconfig for x86_64 and i386. I've runtested the main part of the code on FRV and i386, though I can't test most of the drivers. I've also done partial conversion for powerpc and MIPS - these at least compile with minimal configurations. This will affect all archs. Mostly the changes should be relatively easy. Take do_IRQ(), store the regs pointer at the beginning, saving the old one: struct pt_regs *old_regs = set_irq_regs(regs); And put the old one back at the end: set_irq_regs(old_regs); Don't pass regs through to generic_handle_irq() or __do_IRQ(). In timer_interrupt(), this sort of change will be necessary: - update_process_times(user_mode(regs)); - profile_tick(CPU_PROFILING, regs); + update_process_times(user_mode(get_irq_regs())); + profile_tick(CPU_PROFILING); I'd like to move update_process_times()'s use of get_irq_regs() into itself, except that i386, alone of the archs, uses something other than user_mode(). Some notes on the interrupt handling in the drivers: (*) input_dev() is now gone entirely. The regs pointer is no longer stored in the input_dev struct. (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does something different depending on whether it's been supplied with a regs pointer or not. (*) Various IRQ handler function pointers have been moved to type irq_handler_t. Signed-Off-By: David Howells <dhowells@redhat.com> (cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
2006-10-05 21:55:46 +08:00
static irqreturn_t atmel_interrupt(int irq, void *dev_id)
{
struct uart_port *port = dev_id;
unsigned int status, pending, pass_counter = 0;
do {
status = UART_GET_CSR(port);
pending = status & UART_GET_IMR(port);
if (!pending)
break;
atmel_handle_receive(port, pending);
atmel_handle_status(port, pending, status);
atmel_handle_transmit(port, pending);
} while (pass_counter++ < ATMEL_ISR_PASS_LIMIT);
return pass_counter ? IRQ_HANDLED : IRQ_NONE;
}
/*
* Called from tasklet with ENDTX and TXBUFE interrupts disabled.
*/
static void atmel_tx_dma(struct uart_port *port)
{
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
struct circ_buf *xmit = &port->info->xmit;
struct atmel_dma_buffer *pdc = &atmel_port->pdc_tx;
int count;
/* nothing left to transmit? */
if (UART_GET_TCR(port))
return;
xmit->tail += pdc->ofs;
xmit->tail &= UART_XMIT_SIZE - 1;
port->icount.tx += pdc->ofs;
pdc->ofs = 0;
/* more to transmit - setup next transfer */
/* disable PDC transmit */
UART_PUT_PTCR(port, ATMEL_PDC_TXTDIS);
if (!uart_circ_empty(xmit) && !uart_tx_stopped(port)) {
dma_sync_single_for_device(port->dev,
pdc->dma_addr,
pdc->dma_size,
DMA_TO_DEVICE);
count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
pdc->ofs = count;
UART_PUT_TPR(port, pdc->dma_addr + xmit->tail);
UART_PUT_TCR(port, count);
/* re-enable PDC transmit and interrupts */
UART_PUT_PTCR(port, ATMEL_PDC_TXTEN);
UART_PUT_IER(port, ATMEL_US_ENDTX | ATMEL_US_TXBUFE);
}
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(port);
}
static void atmel_rx_from_ring(struct uart_port *port)
{
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
struct circ_buf *ring = &atmel_port->rx_ring;
unsigned int flg;
unsigned int status;
while (ring->head != ring->tail) {
struct atmel_uart_char c;
/* Make sure c is loaded after head. */
smp_rmb();
c = ((struct atmel_uart_char *)ring->buf)[ring->tail];
ring->tail = (ring->tail + 1) & (ATMEL_SERIAL_RINGSIZE - 1);
port->icount.rx++;
status = c.status;
flg = TTY_NORMAL;
/*
* note that the error handling code is
* out of the main execution path
*/
if (unlikely(status & (ATMEL_US_PARE | ATMEL_US_FRAME
| ATMEL_US_OVRE | ATMEL_US_RXBRK))) {
if (status & ATMEL_US_RXBRK) {
/* ignore side-effect */
status &= ~(ATMEL_US_PARE | ATMEL_US_FRAME);
port->icount.brk++;
if (uart_handle_break(port))
continue;
}
if (status & ATMEL_US_PARE)
port->icount.parity++;
if (status & ATMEL_US_FRAME)
port->icount.frame++;
if (status & ATMEL_US_OVRE)
port->icount.overrun++;
status &= port->read_status_mask;
if (status & ATMEL_US_RXBRK)
flg = TTY_BREAK;
else if (status & ATMEL_US_PARE)
flg = TTY_PARITY;
else if (status & ATMEL_US_FRAME)
flg = TTY_FRAME;
}
if (uart_handle_sysrq_char(port, c.ch))
continue;
uart_insert_char(port, status, ATMEL_US_OVRE, c.ch, flg);
}
/*
* Drop the lock here since it might end up calling
* uart_start(), which takes the lock.
*/
spin_unlock(&port->lock);
tty_flip_buffer_push(port->info->port.tty);
spin_lock(&port->lock);
}
static void atmel_rx_from_dma(struct uart_port *port)
{
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
struct tty_struct *tty = port->info->port.tty;
struct atmel_dma_buffer *pdc;
int rx_idx = atmel_port->pdc_rx_idx;
unsigned int head;
unsigned int tail;
unsigned int count;
do {
/* Reset the UART timeout early so that we don't miss one */
UART_PUT_CR(port, ATMEL_US_STTTO);
pdc = &atmel_port->pdc_rx[rx_idx];
head = UART_GET_RPR(port) - pdc->dma_addr;
tail = pdc->ofs;
/* If the PDC has switched buffers, RPR won't contain
* any address within the current buffer. Since head
* is unsigned, we just need a one-way comparison to
* find out.
*
* In this case, we just need to consume the entire
* buffer and resubmit it for DMA. This will clear the
* ENDRX bit as well, so that we can safely re-enable
* all interrupts below.
*/
head = min(head, pdc->dma_size);
if (likely(head != tail)) {
dma_sync_single_for_cpu(port->dev, pdc->dma_addr,
pdc->dma_size, DMA_FROM_DEVICE);
/*
* head will only wrap around when we recycle
* the DMA buffer, and when that happens, we
* explicitly set tail to 0. So head will
* always be greater than tail.
*/
count = head - tail;
tty_insert_flip_string(tty, pdc->buf + pdc->ofs, count);
dma_sync_single_for_device(port->dev, pdc->dma_addr,
pdc->dma_size, DMA_FROM_DEVICE);
port->icount.rx += count;
pdc->ofs = head;
}
/*
* If the current buffer is full, we need to check if
* the next one contains any additional data.
*/
if (head >= pdc->dma_size) {
pdc->ofs = 0;
UART_PUT_RNPR(port, pdc->dma_addr);
UART_PUT_RNCR(port, pdc->dma_size);
rx_idx = !rx_idx;
atmel_port->pdc_rx_idx = rx_idx;
}
} while (head >= pdc->dma_size);
/*
* Drop the lock here since it might end up calling
* uart_start(), which takes the lock.
*/
spin_unlock(&port->lock);
tty_flip_buffer_push(tty);
spin_lock(&port->lock);
UART_PUT_IER(port, ATMEL_US_ENDRX | ATMEL_US_TIMEOUT);
}
/*
* tasklet handling tty stuff outside the interrupt handler.
*/
static void atmel_tasklet_func(unsigned long data)
{
struct uart_port *port = (struct uart_port *)data;
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
unsigned int status;
unsigned int status_change;
/* The interrupt handler does not take the lock */
spin_lock(&port->lock);
if (atmel_use_dma_tx(port))
atmel_tx_dma(port);
else
atmel_tx_chars(port);
status = atmel_port->irq_status;
status_change = status ^ atmel_port->irq_status_prev;
if (status_change & (ATMEL_US_RI | ATMEL_US_DSR
| ATMEL_US_DCD | ATMEL_US_CTS)) {
/* TODO: All reads to CSR will clear these interrupts! */
if (status_change & ATMEL_US_RI)
port->icount.rng++;
if (status_change & ATMEL_US_DSR)
port->icount.dsr++;
if (status_change & ATMEL_US_DCD)
uart_handle_dcd_change(port, !(status & ATMEL_US_DCD));
if (status_change & ATMEL_US_CTS)
uart_handle_cts_change(port, !(status & ATMEL_US_CTS));
wake_up_interruptible(&port->info->delta_msr_wait);
atmel_port->irq_status_prev = status;
}
if (atmel_use_dma_rx(port))
atmel_rx_from_dma(port);
else
atmel_rx_from_ring(port);
spin_unlock(&port->lock);
}
/*
* Perform initialization and enable port for reception
*/
static int atmel_startup(struct uart_port *port)
{
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
struct tty_struct *tty = port->info->port.tty;
int retval;
/*
* Ensure that no interrupts are enabled otherwise when
* request_irq() is called we could get stuck trying to
* handle an unexpected interrupt
*/
UART_PUT_IDR(port, -1);
/*
* Allocate the IRQ
*/
retval = request_irq(port->irq, atmel_interrupt, IRQF_SHARED,
tty ? tty->name : "atmel_serial", port);
if (retval) {
printk("atmel_serial: atmel_startup - Can't get irq\n");
return retval;
}
/*
* Initialize DMA (if necessary)
*/
if (atmel_use_dma_rx(port)) {
int i;
for (i = 0; i < 2; i++) {
struct atmel_dma_buffer *pdc = &atmel_port->pdc_rx[i];
pdc->buf = kmalloc(PDC_BUFFER_SIZE, GFP_KERNEL);
if (pdc->buf == NULL) {
if (i != 0) {
dma_unmap_single(port->dev,
atmel_port->pdc_rx[0].dma_addr,
PDC_BUFFER_SIZE,
DMA_FROM_DEVICE);
kfree(atmel_port->pdc_rx[0].buf);
}
free_irq(port->irq, port);
return -ENOMEM;
}
pdc->dma_addr = dma_map_single(port->dev,
pdc->buf,
PDC_BUFFER_SIZE,
DMA_FROM_DEVICE);
pdc->dma_size = PDC_BUFFER_SIZE;
pdc->ofs = 0;
}
atmel_port->pdc_rx_idx = 0;
UART_PUT_RPR(port, atmel_port->pdc_rx[0].dma_addr);
UART_PUT_RCR(port, PDC_BUFFER_SIZE);
UART_PUT_RNPR(port, atmel_port->pdc_rx[1].dma_addr);
UART_PUT_RNCR(port, PDC_BUFFER_SIZE);
}
if (atmel_use_dma_tx(port)) {
struct atmel_dma_buffer *pdc = &atmel_port->pdc_tx;
struct circ_buf *xmit = &port->info->xmit;
pdc->buf = xmit->buf;
pdc->dma_addr = dma_map_single(port->dev,
pdc->buf,
UART_XMIT_SIZE,
DMA_TO_DEVICE);
pdc->dma_size = UART_XMIT_SIZE;
pdc->ofs = 0;
}
/*
* If there is a specific "open" function (to register
* control line interrupts)
*/
if (atmel_open_hook) {
retval = atmel_open_hook(port);
if (retval) {
free_irq(port->irq, port);
return retval;
}
}
atmel_serial might lose modem status change I found a problem of handling of modem status of atmel_serial driver. With the commit 1ecc26 ("atmel_serial: split the interrupt handler"), handling of modem status signal was splitted into two parts. The atmel_tasklet_func() compares new status with irq_status_prev, but irq_status_prev is not correct if signal status was changed while the port is closed. Here is a sequence to cause problem: 1. Remote side sets CTS (and DSR). 2. Local side close the port. 3. Local side clears RTS and DTR. 4. Remote side clears CTS and DSR. 5. Local side reopen the port. hw_stopped becomes 1. 6. Local side sets RTS and DTR. 7. Remote side sets CTS and DSR. Then CTS change interrupt can be received, but since CTS bit in irq_status_prev and new status is same, uart_handle_cts_change() will not be called (so hw_stopped will not be cleared, i.e. cannot send any data). I suppose irq_status_prev should be initialized at somewhere in open sequence. Itai Levi pointed out that we need to initialize atmel_port->irq_status as well here. His analysis is as follows: > Regarding the second part of the patch (which resets irq_status_prev), > it turns out that both versions of the patch (mine and Atsushi's) > still leave enough room for faulty behavior when opening the port. > > This is because we are not resetting both irq_status_prev and > irq_status in atmel_startup() to CSR, which leads faulty behavior in > the following sequences: > > First case: > 1. closing the port while CTS line = 1 (TX not allowed) > 2. setting CTS line = 0 (TX allowed) > 3. opening the port > 4. transmitting one char > 5. Cannot transmit more chars, although CTS line is 0 > > Second case: > 1. closing the port while CTS line = 0 (TX allowed) > 2. setting CTS line = 1 (TX not allowed) > 3. opening the port > 4. receiving some chars > 5. Now we can transmit, although CTS line is 1 > > This reason for this is that the tasklet is scheduled as a result of > TX or RX interrupts (not a status change!), in steps 4 above. Inside > the tasklet, the atmel_port->irq_status (which holds the value from > the previous session) is compared to atmel_port->irq_status_prev. > Hence, a status-change of the CTS line is faultily detected. > > Both cases were verified on 9260 hardware. [haavard.skinnemoen@atmel.com: folded with patch from Itai Levi] Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp> Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com> Cc: Remy Bohmer <linux@bohmer.net> Cc: Marc Pignat <marc.pignat@hevs.ch> Cc: Itai Levi <itai.levi.devel@gmail.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-19 06:48:28 +08:00
/* Save current CSR for comparison in atmel_tasklet_func() */
atmel_port->irq_status_prev = UART_GET_CSR(port);
atmel_port->irq_status = atmel_port->irq_status_prev;
/*
* Finally, enable the serial port
*/
UART_PUT_CR(port, ATMEL_US_RSTSTA | ATMEL_US_RSTRX);
/* enable xmit & rcvr */
UART_PUT_CR(port, ATMEL_US_TXEN | ATMEL_US_RXEN);
if (atmel_use_dma_rx(port)) {
/* set UART timeout */
UART_PUT_RTOR(port, PDC_RX_TIMEOUT);
UART_PUT_CR(port, ATMEL_US_STTTO);
UART_PUT_IER(port, ATMEL_US_ENDRX | ATMEL_US_TIMEOUT);
/* enable PDC controller */
UART_PUT_PTCR(port, ATMEL_PDC_RXTEN);
} else {
/* enable receive only */
UART_PUT_IER(port, ATMEL_US_RXRDY);
}
return 0;
}
/*
* Disable the port
*/
static void atmel_shutdown(struct uart_port *port)
{
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
/*
* Ensure everything is stopped.
*/
atmel_stop_rx(port);
atmel_stop_tx(port);
/*
* Shut-down the DMA.
*/
if (atmel_use_dma_rx(port)) {
int i;
for (i = 0; i < 2; i++) {
struct atmel_dma_buffer *pdc = &atmel_port->pdc_rx[i];
dma_unmap_single(port->dev,
pdc->dma_addr,
pdc->dma_size,
DMA_FROM_DEVICE);
kfree(pdc->buf);
}
}
if (atmel_use_dma_tx(port)) {
struct atmel_dma_buffer *pdc = &atmel_port->pdc_tx;
dma_unmap_single(port->dev,
pdc->dma_addr,
pdc->dma_size,
DMA_TO_DEVICE);
}
/*
* Disable all interrupts, port and break condition.
*/
UART_PUT_CR(port, ATMEL_US_RSTSTA);
UART_PUT_IDR(port, -1);
/*
* Free the interrupt
*/
free_irq(port->irq, port);
/*
* If there is a specific "close" function (to unregister
* control line interrupts)
*/
if (atmel_close_hook)
atmel_close_hook(port);
}
/*
* Flush any TX data submitted for DMA. Called when the TX circular
* buffer is reset.
*/
static void atmel_flush_buffer(struct uart_port *port)
{
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
if (atmel_use_dma_tx(port)) {
UART_PUT_TCR(port, 0);
atmel_port->pdc_tx.ofs = 0;
}
}
/*
* Power / Clock management.
*/
static void atmel_serial_pm(struct uart_port *port, unsigned int state,
unsigned int oldstate)
{
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
switch (state) {
case 0:
/*
* Enable the peripheral clock for this serial port.
* This is called on uart_open() or a resume event.
*/
clk_enable(atmel_port->clk);
/* re-enable interrupts if we disabled some on suspend */
UART_PUT_IER(port, atmel_port->backup_imr);
break;
case 3:
/* Back up the interrupt mask and disable all interrupts */
atmel_port->backup_imr = UART_GET_IMR(port);
UART_PUT_IDR(port, -1);
/*
* Disable the peripheral clock for this serial port.
* This is called on uart_close() or a suspend event.
*/
clk_disable(atmel_port->clk);
break;
default:
printk(KERN_ERR "atmel_serial: unknown pm %d\n", state);
}
}
/*
* Change the port parameters
*/
static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,
struct ktermios *old)
{
unsigned long flags;
unsigned int mode, imr, quot, baud;
/* Get current mode register */
mode = UART_GET_MR(port) & ~(ATMEL_US_USCLKS | ATMEL_US_CHRL
| ATMEL_US_NBSTOP | ATMEL_US_PAR
| ATMEL_US_USMODE);
baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16);
quot = uart_get_divisor(port, baud);
if (quot > 65535) { /* BRGR is 16-bit, so switch to slower clock */
quot /= 8;
mode |= ATMEL_US_USCLKS_MCK_DIV8;
}
/* byte size */
switch (termios->c_cflag & CSIZE) {
case CS5:
mode |= ATMEL_US_CHRL_5;
break;
case CS6:
mode |= ATMEL_US_CHRL_6;
break;
case CS7:
mode |= ATMEL_US_CHRL_7;
break;
default:
mode |= ATMEL_US_CHRL_8;
break;
}
/* stop bits */
if (termios->c_cflag & CSTOPB)
mode |= ATMEL_US_NBSTOP_2;
/* parity */
if (termios->c_cflag & PARENB) {
/* Mark or Space parity */
if (termios->c_cflag & CMSPAR) {
if (termios->c_cflag & PARODD)
mode |= ATMEL_US_PAR_MARK;
else
mode |= ATMEL_US_PAR_SPACE;
} else if (termios->c_cflag & PARODD)
mode |= ATMEL_US_PAR_ODD;
else
mode |= ATMEL_US_PAR_EVEN;
} else
mode |= ATMEL_US_PAR_NONE;
/* hardware handshake (RTS/CTS) */
if (termios->c_cflag & CRTSCTS)
mode |= ATMEL_US_USMODE_HWHS;
else
mode |= ATMEL_US_USMODE_NORMAL;
spin_lock_irqsave(&port->lock, flags);
port->read_status_mask = ATMEL_US_OVRE;
if (termios->c_iflag & INPCK)
port->read_status_mask |= (ATMEL_US_FRAME | ATMEL_US_PARE);
if (termios->c_iflag & (BRKINT | PARMRK))
port->read_status_mask |= ATMEL_US_RXBRK;
if (atmel_use_dma_rx(port))
/* need to enable error interrupts */
UART_PUT_IER(port, port->read_status_mask);
/*
* Characters to ignore
*/
port->ignore_status_mask = 0;
if (termios->c_iflag & IGNPAR)
port->ignore_status_mask |= (ATMEL_US_FRAME | ATMEL_US_PARE);
if (termios->c_iflag & IGNBRK) {
port->ignore_status_mask |= ATMEL_US_RXBRK;
/*
* If we're ignoring parity and break indicators,
* ignore overruns too (for real raw support).
*/
if (termios->c_iflag & IGNPAR)
port->ignore_status_mask |= ATMEL_US_OVRE;
}
/* TODO: Ignore all characters if CREAD is set.*/
/* update the per-port timeout */
uart_update_timeout(port, termios->c_cflag, baud);
/* save/disable interrupts and drain transmitter */
imr = UART_GET_IMR(port);
UART_PUT_IDR(port, -1);
while (!(UART_GET_CSR(port) & ATMEL_US_TXEMPTY))
cpu_relax();
/* disable receiver and transmitter */
UART_PUT_CR(port, ATMEL_US_TXDIS | ATMEL_US_RXDIS);
/* set the parity, stop bits and data size */
UART_PUT_MR(port, mode);
/* set the baud rate */
UART_PUT_BRGR(port, quot);
UART_PUT_CR(port, ATMEL_US_RSTSTA | ATMEL_US_RSTRX);
UART_PUT_CR(port, ATMEL_US_TXEN | ATMEL_US_RXEN);
/* restore interrupts */
UART_PUT_IER(port, imr);
/* CTS flow-control and modem-status interrupts */
if (UART_ENABLE_MS(port, termios->c_cflag))
port->ops->enable_ms(port);
spin_unlock_irqrestore(&port->lock, flags);
}
/*
* Return string describing the specified port
*/
static const char *atmel_type(struct uart_port *port)
{
return (port->type == PORT_ATMEL) ? "ATMEL_SERIAL" : NULL;
}
/*
* Release the memory region(s) being used by 'port'.
*/
static void atmel_release_port(struct uart_port *port)
{
struct platform_device *pdev = to_platform_device(port->dev);
int size = pdev->resource[0].end - pdev->resource[0].start + 1;
release_mem_region(port->mapbase, size);
if (port->flags & UPF_IOREMAP) {
iounmap(port->membase);
port->membase = NULL;
}
}
/*
* Request the memory region(s) being used by 'port'.
*/
static int atmel_request_port(struct uart_port *port)
{
struct platform_device *pdev = to_platform_device(port->dev);
int size = pdev->resource[0].end - pdev->resource[0].start + 1;
if (!request_mem_region(port->mapbase, size, "atmel_serial"))
return -EBUSY;
if (port->flags & UPF_IOREMAP) {
port->membase = ioremap(port->mapbase, size);
if (port->membase == NULL) {
release_mem_region(port->mapbase, size);
return -ENOMEM;
}
}
return 0;
}
/*
* Configure/autoconfigure the port.
*/
static void atmel_config_port(struct uart_port *port, int flags)
{
if (flags & UART_CONFIG_TYPE) {
port->type = PORT_ATMEL;
atmel_request_port(port);
}
}
/*
* Verify the new serial_struct (for TIOCSSERIAL).
*/
static int atmel_verify_port(struct uart_port *port, struct serial_struct *ser)
{
int ret = 0;
if (ser->type != PORT_UNKNOWN && ser->type != PORT_ATMEL)
ret = -EINVAL;
if (port->irq != ser->irq)
ret = -EINVAL;
if (ser->io_type != SERIAL_IO_MEM)
ret = -EINVAL;
if (port->uartclk / 16 != ser->baud_base)
ret = -EINVAL;
if ((void *)port->mapbase != ser->iomem_base)
ret = -EINVAL;
if (port->iobase != ser->port)
ret = -EINVAL;
if (ser->hub6 != 0)
ret = -EINVAL;
return ret;
}
static struct uart_ops atmel_pops = {
.tx_empty = atmel_tx_empty,
.set_mctrl = atmel_set_mctrl,
.get_mctrl = atmel_get_mctrl,
.stop_tx = atmel_stop_tx,
.start_tx = atmel_start_tx,
.stop_rx = atmel_stop_rx,
.enable_ms = atmel_enable_ms,
.break_ctl = atmel_break_ctl,
.startup = atmel_startup,
.shutdown = atmel_shutdown,
.flush_buffer = atmel_flush_buffer,
.set_termios = atmel_set_termios,
.type = atmel_type,
.release_port = atmel_release_port,
.request_port = atmel_request_port,
.config_port = atmel_config_port,
.verify_port = atmel_verify_port,
.pm = atmel_serial_pm,
};
/*
* Configure the port from the platform device resource info.
*/
static void __devinit atmel_init_port(struct atmel_uart_port *atmel_port,
struct platform_device *pdev)
{
struct uart_port *port = &atmel_port->uart;
struct atmel_uart_data *data = pdev->dev.platform_data;
port->iotype = UPIO_MEM;
port->flags = UPF_BOOT_AUTOCONF;
port->ops = &atmel_pops;
port->fifosize = 1;
port->line = pdev->id;
port->dev = &pdev->dev;
port->mapbase = pdev->resource[0].start;
port->irq = pdev->resource[1].start;
tasklet_init(&atmel_port->tasklet, atmel_tasklet_func,
(unsigned long)port);
memset(&atmel_port->rx_ring, 0, sizeof(atmel_port->rx_ring));
if (data->regs)
/* Already mapped by setup code */
port->membase = data->regs;
else {
port->flags |= UPF_IOREMAP;
port->membase = NULL;
}
/* for console, the clock could already be configured */
if (!atmel_port->clk) {
atmel_port->clk = clk_get(&pdev->dev, "usart");
clk_enable(atmel_port->clk);
port->uartclk = clk_get_rate(atmel_port->clk);
clk_disable(atmel_port->clk);
/* only enable clock when USART is in use */
}
atmel_port->use_dma_rx = data->use_dma_rx;
atmel_port->use_dma_tx = data->use_dma_tx;
if (atmel_use_dma_tx(port))
port->fifosize = PDC_BUFFER_SIZE;
}
/*
* Register board-specific modem-control line handlers.
*/
void __init atmel_register_uart_fns(struct atmel_port_fns *fns)
{
if (fns->enable_ms)
atmel_pops.enable_ms = fns->enable_ms;
if (fns->get_mctrl)
atmel_pops.get_mctrl = fns->get_mctrl;
if (fns->set_mctrl)
atmel_pops.set_mctrl = fns->set_mctrl;
atmel_open_hook = fns->open;
atmel_close_hook = fns->close;
atmel_pops.pm = fns->pm;
atmel_pops.set_wake = fns->set_wake;
}
#ifdef CONFIG_SERIAL_ATMEL_CONSOLE
static void atmel_console_putchar(struct uart_port *port, int ch)
{
while (!(UART_GET_CSR(port) & ATMEL_US_TXRDY))
cpu_relax();
UART_PUT_CHAR(port, ch);
}
/*
* Interrupts are disabled on entering
*/
static void atmel_console_write(struct console *co, const char *s, u_int count)
{
struct uart_port *port = &atmel_ports[co->index].uart;
unsigned int status, imr;
unsigned int pdc_tx;
/*
* First, save IMR and then disable interrupts
*/
imr = UART_GET_IMR(port);
UART_PUT_IDR(port, ATMEL_US_RXRDY | ATMEL_US_TXRDY);
/* Store PDC transmit status and disable it */
pdc_tx = UART_GET_PTSR(port) & ATMEL_PDC_TXTEN;
UART_PUT_PTCR(port, ATMEL_PDC_TXTDIS);
uart_console_write(port, s, count, atmel_console_putchar);
/*
* Finally, wait for transmitter to become empty
* and restore IMR
*/
do {
status = UART_GET_CSR(port);
} while (!(status & ATMEL_US_TXRDY));
/* Restore PDC transmit status */
if (pdc_tx)
UART_PUT_PTCR(port, ATMEL_PDC_TXTEN);
/* set interrupts back the way they were */
UART_PUT_IER(port, imr);
}
/*
* If the port was already initialised (eg, by a boot loader),
* try to determine the current setup.
*/
static void __init atmel_console_get_options(struct uart_port *port, int *baud,
int *parity, int *bits)
{
unsigned int mr, quot;
/*
* If the baud rate generator isn't running, the port wasn't
* initialized by the boot loader.
*/
quot = UART_GET_BRGR(port) & ATMEL_US_CD;
if (!quot)
return;
mr = UART_GET_MR(port) & ATMEL_US_CHRL;
if (mr == ATMEL_US_CHRL_8)
*bits = 8;
else
*bits = 7;
mr = UART_GET_MR(port) & ATMEL_US_PAR;
if (mr == ATMEL_US_PAR_EVEN)
*parity = 'e';
else if (mr == ATMEL_US_PAR_ODD)
*parity = 'o';
/*
* The serial core only rounds down when matching this to a
* supported baud rate. Make sure we don't end up slightly
* lower than one of those, as it would make us fall through
* to a much lower baud rate than we really want.
*/
*baud = port->uartclk / (16 * (quot - 1));
}
static int __init atmel_console_setup(struct console *co, char *options)
{
struct uart_port *port = &atmel_ports[co->index].uart;
int baud = 115200;
int bits = 8;
int parity = 'n';
int flow = 'n';
if (port->membase == NULL) {
/* Port not initialized yet - delay setup */
return -ENODEV;
}
clk_enable(atmel_ports[co->index].clk);
UART_PUT_IDR(port, -1);
UART_PUT_CR(port, ATMEL_US_RSTSTA | ATMEL_US_RSTRX);
UART_PUT_CR(port, ATMEL_US_TXEN | ATMEL_US_RXEN);
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
else
atmel_console_get_options(port, &baud, &parity, &bits);
return uart_set_options(port, co, baud, parity, bits, flow);
}
static struct uart_driver atmel_uart;
static struct console atmel_console = {
.name = ATMEL_DEVICENAME,
.write = atmel_console_write,
.device = uart_console_device,
.setup = atmel_console_setup,
.flags = CON_PRINTBUFFER,
.index = -1,
.data = &atmel_uart,
};
#define ATMEL_CONSOLE_DEVICE (&atmel_console)
/*
* Early console initialization (before VM subsystem initialized).
*/
static int __init atmel_console_init(void)
{
if (atmel_default_console_device) {
add_preferred_console(ATMEL_DEVICENAME,
atmel_default_console_device->id, NULL);
atmel_init_port(&atmel_ports[atmel_default_console_device->id],
atmel_default_console_device);
register_console(&atmel_console);
}
return 0;
}
console_initcall(atmel_console_init);
/*
* Late console initialization.
*/
static int __init atmel_late_console_init(void)
{
if (atmel_default_console_device
&& !(atmel_console.flags & CON_ENABLED))
register_console(&atmel_console);
return 0;
}
core_initcall(atmel_late_console_init);
static inline bool atmel_is_console_port(struct uart_port *port)
{
return port->cons && port->cons->index == port->line;
}
#else
#define ATMEL_CONSOLE_DEVICE NULL
static inline bool atmel_is_console_port(struct uart_port *port)
{
return false;
}
#endif
static struct uart_driver atmel_uart = {
.owner = THIS_MODULE,
.driver_name = "atmel_serial",
.dev_name = ATMEL_DEVICENAME,
.major = SERIAL_ATMEL_MAJOR,
.minor = MINOR_START,
.nr = ATMEL_MAX_UART,
.cons = ATMEL_CONSOLE_DEVICE,
};
#ifdef CONFIG_PM
static bool atmel_serial_clk_will_stop(void)
{
#ifdef CONFIG_ARCH_AT91
return at91_suspend_entering_slow_clock();
#else
return false;
#endif
}
static int atmel_serial_suspend(struct platform_device *pdev,
pm_message_t state)
{
struct uart_port *port = platform_get_drvdata(pdev);
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
if (atmel_is_console_port(port) && console_suspend_enabled) {
/* Drain the TX shifter */
while (!(UART_GET_CSR(port) & ATMEL_US_TXEMPTY))
cpu_relax();
}
/* we can not wake up if we're running on slow clock */
atmel_port->may_wakeup = device_may_wakeup(&pdev->dev);
if (atmel_serial_clk_will_stop())
device_set_wakeup_enable(&pdev->dev, 0);
uart_suspend_port(&atmel_uart, port);
return 0;
}
static int atmel_serial_resume(struct platform_device *pdev)
{
struct uart_port *port = platform_get_drvdata(pdev);
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
uart_resume_port(&atmel_uart, port);
device_set_wakeup_enable(&pdev->dev, atmel_port->may_wakeup);
return 0;
}
#else
#define atmel_serial_suspend NULL
#define atmel_serial_resume NULL
#endif
static int __devinit atmel_serial_probe(struct platform_device *pdev)
{
struct atmel_uart_port *port;
void *data;
int ret;
BUILD_BUG_ON(!is_power_of_2(ATMEL_SERIAL_RINGSIZE));
port = &atmel_ports[pdev->id];
port->backup_imr = 0;
atmel_init_port(port, pdev);
if (!atmel_use_dma_rx(&port->uart)) {
ret = -ENOMEM;
data = kmalloc(sizeof(struct atmel_uart_char)
* ATMEL_SERIAL_RINGSIZE, GFP_KERNEL);
if (!data)
goto err_alloc_ring;
port->rx_ring.buf = data;
}
ret = uart_add_one_port(&atmel_uart, &port->uart);
if (ret)
goto err_add_port;
if (atmel_is_console_port(&port->uart)
&& ATMEL_CONSOLE_DEVICE->flags & CON_ENABLED) {
/*
* The serial core enabled the clock for us, so undo
* the clk_enable() in atmel_console_setup()
*/
clk_disable(port->clk);
}
device_init_wakeup(&pdev->dev, 1);
platform_set_drvdata(pdev, port);
return 0;
err_add_port:
kfree(port->rx_ring.buf);
port->rx_ring.buf = NULL;
err_alloc_ring:
if (!atmel_is_console_port(&port->uart)) {
clk_put(port->clk);
port->clk = NULL;
}
return ret;
}
static int __devexit atmel_serial_remove(struct platform_device *pdev)
{
struct uart_port *port = platform_get_drvdata(pdev);
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
int ret = 0;
device_init_wakeup(&pdev->dev, 0);
platform_set_drvdata(pdev, NULL);
ret = uart_remove_one_port(&atmel_uart, port);
tasklet_kill(&atmel_port->tasklet);
kfree(atmel_port->rx_ring.buf);
/* "port" is allocated statically, so we shouldn't free it */
clk_put(atmel_port->clk);
return ret;
}
static struct platform_driver atmel_serial_driver = {
.probe = atmel_serial_probe,
.remove = __devexit_p(atmel_serial_remove),
.suspend = atmel_serial_suspend,
.resume = atmel_serial_resume,
.driver = {
.name = "atmel_usart",
.owner = THIS_MODULE,
},
};
static int __init atmel_serial_init(void)
{
int ret;
ret = uart_register_driver(&atmel_uart);
if (ret)
return ret;
ret = platform_driver_register(&atmel_serial_driver);
if (ret)
uart_unregister_driver(&atmel_uart);
return ret;
}
static void __exit atmel_serial_exit(void)
{
platform_driver_unregister(&atmel_serial_driver);
uart_unregister_driver(&atmel_uart);
}
module_init(atmel_serial_init);
module_exit(atmel_serial_exit);
MODULE_AUTHOR("Rick Bronson");
MODULE_DESCRIPTION("Atmel AT91 / AT32 serial port driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:atmel_usart");