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u-boot/drivers/serial/ns16550.c
Simon Goldschmidt c4448bdc4f serial: ns16550: fix debug uart putc called before init 
If _debug_uart_putc() is called before _debug_uart_init(), the
ns16550 debug uart driver hangs in a tight loop waiting for the
tx FIFO to get empty.

As this can happen via a printf sneaking in before the port calls
debug_uart_init(), introduce a config option to ignore characters
before the debug uart is initialized.

This is done by reading the baudrate divisor and aborting if is zero.

The Kconfig option is required as reading the baudrate divisor does
not seem to work for all ns16500 compatibles (which is why the last
attempt on this has been reverted in 1a67969a99).

Tested on socfpga_cyclone5_socrates.

Signed-off-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2019-01-15 15:28:52 -05:00

560 lines
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/*
* COM1 NS16550 support
* originally from linux source (arch/powerpc/boot/ns16550.c)
* modified to use CONFIG_SYS_ISA_MEM and new defines
*/
#include <common.h>
#include <clk.h>
#include <dm.h>
#include <errno.h>
#include <ns16550.h>
#include <reset.h>
#include <serial.h>
#include <watchdog.h>
#include <linux/types.h>
#include <asm/io.h>
DECLARE_GLOBAL_DATA_PTR;
#define UART_LCRVAL UART_LCR_8N1 /* 8 data, 1 stop, no parity */
#define UART_MCRVAL (UART_MCR_DTR | \
UART_MCR_RTS) /* RTS/DTR */
#ifndef CONFIG_DM_SERIAL
#ifdef CONFIG_SYS_NS16550_PORT_MAPPED
#define serial_out(x, y) outb(x, (ulong)y)
#define serial_in(y) inb((ulong)y)
#elif defined(CONFIG_SYS_NS16550_MEM32) && (CONFIG_SYS_NS16550_REG_SIZE > 0)
#define serial_out(x, y) out_be32(y, x)
#define serial_in(y) in_be32(y)
#elif defined(CONFIG_SYS_NS16550_MEM32) && (CONFIG_SYS_NS16550_REG_SIZE < 0)
#define serial_out(x, y) out_le32(y, x)
#define serial_in(y) in_le32(y)
#else
#define serial_out(x, y) writeb(x, y)
#define serial_in(y) readb(y)
#endif
#endif /* !CONFIG_DM_SERIAL */
#if defined(CONFIG_SOC_KEYSTONE)
#define UART_REG_VAL_PWREMU_MGMT_UART_DISABLE 0
#define UART_REG_VAL_PWREMU_MGMT_UART_ENABLE ((1 << 14) | (1 << 13) | (1 << 0))
#undef UART_MCRVAL
#ifdef CONFIG_SERIAL_HW_FLOW_CONTROL
#define UART_MCRVAL (UART_MCR_RTS | UART_MCR_AFE)
#else
#define UART_MCRVAL (UART_MCR_RTS)
#endif
#endif
#ifndef CONFIG_SYS_NS16550_IER
#define CONFIG_SYS_NS16550_IER 0x00
#endif /* CONFIG_SYS_NS16550_IER */
static inline void serial_out_shift(void *addr, int shift, int value)
{
#ifdef CONFIG_SYS_NS16550_PORT_MAPPED
outb(value, (ulong)addr);
#elif defined(CONFIG_SYS_NS16550_MEM32) && defined(CONFIG_SYS_LITTLE_ENDIAN)
out_le32(addr, value);
#elif defined(CONFIG_SYS_NS16550_MEM32) && defined(CONFIG_SYS_BIG_ENDIAN)
out_be32(addr, value);
#elif defined(CONFIG_SYS_NS16550_MEM32)
writel(value, addr);
#elif defined(CONFIG_SYS_BIG_ENDIAN)
writeb(value, addr + (1 << shift) - 1);
#else
writeb(value, addr);
#endif
}
static inline int serial_in_shift(void *addr, int shift)
{
#ifdef CONFIG_SYS_NS16550_PORT_MAPPED
return inb((ulong)addr);
#elif defined(CONFIG_SYS_NS16550_MEM32) && defined(CONFIG_SYS_LITTLE_ENDIAN)
return in_le32(addr);
#elif defined(CONFIG_SYS_NS16550_MEM32) && defined(CONFIG_SYS_BIG_ENDIAN)
return in_be32(addr);
#elif defined(CONFIG_SYS_NS16550_MEM32)
return readl(addr);
#elif defined(CONFIG_SYS_BIG_ENDIAN)
return readb(addr + (1 << shift) - 1);
#else
return readb(addr);
#endif
}
#ifdef CONFIG_DM_SERIAL
#ifndef CONFIG_SYS_NS16550_CLK
#define CONFIG_SYS_NS16550_CLK 0
#endif
static void ns16550_writeb(NS16550_t port, int offset, int value)
{
struct ns16550_platdata *plat = port->plat;
unsigned char *addr;
offset *= 1 << plat->reg_shift;
addr = (unsigned char *)plat->base + offset;
/*
* As far as we know it doesn't make sense to support selection of
* these options at run-time, so use the existing CONFIG options.
*/
serial_out_shift(addr + plat->reg_offset, plat->reg_shift, value);
}
static int ns16550_readb(NS16550_t port, int offset)
{
struct ns16550_platdata *plat = port->plat;
unsigned char *addr;
offset *= 1 << plat->reg_shift;
addr = (unsigned char *)plat->base + offset;
return serial_in_shift(addr + plat->reg_offset, plat->reg_shift);
}
static u32 ns16550_getfcr(NS16550_t port)
{
struct ns16550_platdata *plat = port->plat;
return plat->fcr;
}
/* We can clean these up once everything is moved to driver model */
#define serial_out(value, addr) \
ns16550_writeb(com_port, \
(unsigned char *)addr - (unsigned char *)com_port, value)
#define serial_in(addr) \
ns16550_readb(com_port, \
(unsigned char *)addr - (unsigned char *)com_port)
#else
static u32 ns16550_getfcr(NS16550_t port)
{
return UART_FCR_DEFVAL;
}
#endif
int ns16550_calc_divisor(NS16550_t port, int clock, int baudrate)
{
const unsigned int mode_x_div = 16;
return DIV_ROUND_CLOSEST(clock, mode_x_div * baudrate);
}
static void NS16550_setbrg(NS16550_t com_port, int baud_divisor)
{
/* to keep serial format, read lcr before writing BKSE */
int lcr_val = serial_in(&com_port->lcr) & ~UART_LCR_BKSE;
serial_out(UART_LCR_BKSE | lcr_val, &com_port->lcr);
serial_out(baud_divisor & 0xff, &com_port->dll);
serial_out((baud_divisor >> 8) & 0xff, &com_port->dlm);
serial_out(lcr_val, &com_port->lcr);
}
void NS16550_init(NS16550_t com_port, int baud_divisor)
{
#if (defined(CONFIG_SPL_BUILD) && \
(defined(CONFIG_OMAP34XX) || defined(CONFIG_OMAP44XX)))
/*
* On some OMAP3/OMAP4 devices when UART3 is configured for boot mode
* before SPL starts only THRE bit is set. We have to empty the
* transmitter before initialization starts.
*/
if ((serial_in(&com_port->lsr) & (UART_LSR_TEMT | UART_LSR_THRE))
== UART_LSR_THRE) {
if (baud_divisor != -1)
NS16550_setbrg(com_port, baud_divisor);
serial_out(0, &com_port->mdr1);
}
#endif
while (!(serial_in(&com_port->lsr) & UART_LSR_TEMT))
;
serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier);
#if defined(CONFIG_ARCH_OMAP2PLUS) || defined(CONFIG_OMAP_SERIAL)
serial_out(0x7, &com_port->mdr1); /* mode select reset TL16C750*/
#endif
serial_out(UART_MCRVAL, &com_port->mcr);
serial_out(ns16550_getfcr(com_port), &com_port->fcr);
/* initialize serial config to 8N1 before writing baudrate */
serial_out(UART_LCRVAL, &com_port->lcr);
if (baud_divisor != -1)
NS16550_setbrg(com_port, baud_divisor);
#if defined(CONFIG_ARCH_OMAP2PLUS) || defined(CONFIG_SOC_DA8XX) || \
defined(CONFIG_OMAP_SERIAL)
/* /16 is proper to hit 115200 with 48MHz */
serial_out(0, &com_port->mdr1);
#endif
#if defined(CONFIG_SOC_KEYSTONE)
serial_out(UART_REG_VAL_PWREMU_MGMT_UART_ENABLE, &com_port->regC);
#endif
}
#ifndef CONFIG_NS16550_MIN_FUNCTIONS
void NS16550_reinit(NS16550_t com_port, int baud_divisor)
{
serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier);
NS16550_setbrg(com_port, 0);
serial_out(UART_MCRVAL, &com_port->mcr);
serial_out(ns16550_getfcr(com_port), &com_port->fcr);
NS16550_setbrg(com_port, baud_divisor);
}
#endif /* CONFIG_NS16550_MIN_FUNCTIONS */
void NS16550_putc(NS16550_t com_port, char c)
{
while ((serial_in(&com_port->lsr) & UART_LSR_THRE) == 0)
;
serial_out(c, &com_port->thr);
/*
* Call watchdog_reset() upon newline. This is done here in putc
* since the environment code uses a single puts() to print the complete
* environment upon "printenv". So we can't put this watchdog call
* in puts().
*/
if (c == '\n')
WATCHDOG_RESET();
}
#ifndef CONFIG_NS16550_MIN_FUNCTIONS
char NS16550_getc(NS16550_t com_port)
{
while ((serial_in(&com_port->lsr) & UART_LSR_DR) == 0) {
#if !defined(CONFIG_SPL_BUILD) && defined(CONFIG_USB_TTY)
extern void usbtty_poll(void);
usbtty_poll();
#endif
WATCHDOG_RESET();
}
return serial_in(&com_port->rbr);
}
int NS16550_tstc(NS16550_t com_port)
{
return (serial_in(&com_port->lsr) & UART_LSR_DR) != 0;
}
#endif /* CONFIG_NS16550_MIN_FUNCTIONS */
#ifdef CONFIG_DEBUG_UART_NS16550
#include <debug_uart.h>
static inline void _debug_uart_init(void)
{
struct NS16550 *com_port = (struct NS16550 *)CONFIG_DEBUG_UART_BASE;
int baud_divisor;
/*
* We copy the code from above because it is already horribly messy.
* Trying to refactor to nicely remove the duplication doesn't seem
* feasible. The better fix is to move all users of this driver to
* driver model.
*/
baud_divisor = ns16550_calc_divisor(com_port, CONFIG_DEBUG_UART_CLOCK,
CONFIG_BAUDRATE);
serial_dout(&com_port->ier, CONFIG_SYS_NS16550_IER);
serial_dout(&com_port->mcr, UART_MCRVAL);
serial_dout(&com_port->fcr, UART_FCR_DEFVAL);
serial_dout(&com_port->lcr, UART_LCR_BKSE | UART_LCRVAL);
serial_dout(&com_port->dll, baud_divisor & 0xff);
serial_dout(&com_port->dlm, (baud_divisor >> 8) & 0xff);
serial_dout(&com_port->lcr, UART_LCRVAL);
}
static inline int NS16550_read_baud_divisor(struct NS16550 *com_port)
{
int ret;
serial_dout(&com_port->lcr, UART_LCR_BKSE | UART_LCRVAL);
ret = serial_din(&com_port->dll) & 0xff;
ret |= (serial_din(&com_port->dlm) & 0xff) << 8;
serial_dout(&com_port->lcr, UART_LCRVAL);
return ret;
}
static inline void _debug_uart_putc(int ch)
{
struct NS16550 *com_port = (struct NS16550 *)CONFIG_DEBUG_UART_BASE;
while (!(serial_din(&com_port->lsr) & UART_LSR_THRE)) {
#ifdef CONFIG_DEBUG_UART_NS16550_CHECK_ENABLED
if (!NS16550_read_baud_divisor(com_port))
return;
#endif
}
serial_dout(&com_port->thr, ch);
}
DEBUG_UART_FUNCS
#endif
#ifdef CONFIG_DM_SERIAL
static int ns16550_serial_putc(struct udevice *dev, const char ch)
{
struct NS16550 *const com_port = dev_get_priv(dev);
if (!(serial_in(&com_port->lsr) & UART_LSR_THRE))
return -EAGAIN;
serial_out(ch, &com_port->thr);
/*
* Call watchdog_reset() upon newline. This is done here in putc
* since the environment code uses a single puts() to print the complete
* environment upon "printenv". So we can't put this watchdog call
* in puts().
*/
if (ch == '\n')
WATCHDOG_RESET();
return 0;
}
static int ns16550_serial_pending(struct udevice *dev, bool input)
{
struct NS16550 *const com_port = dev_get_priv(dev);
if (input)
return (serial_in(&com_port->lsr) & UART_LSR_DR) ? 1 : 0;
else
return (serial_in(&com_port->lsr) & UART_LSR_THRE) ? 0 : 1;
}
static int ns16550_serial_getc(struct udevice *dev)
{
struct NS16550 *const com_port = dev_get_priv(dev);
if (!(serial_in(&com_port->lsr) & UART_LSR_DR))
return -EAGAIN;
return serial_in(&com_port->rbr);
}
static int ns16550_serial_setbrg(struct udevice *dev, int baudrate)
{
struct NS16550 *const com_port = dev_get_priv(dev);
struct ns16550_platdata *plat = com_port->plat;
int clock_divisor;
clock_divisor = ns16550_calc_divisor(com_port, plat->clock, baudrate);
NS16550_setbrg(com_port, clock_divisor);
return 0;
}
static int ns16550_serial_setconfig(struct udevice *dev, uint serial_config)
{
struct NS16550 *const com_port = dev_get_priv(dev);
int lcr_val = UART_LCR_WLS_8;
uint parity = SERIAL_GET_PARITY(serial_config);
uint bits = SERIAL_GET_BITS(serial_config);
uint stop = SERIAL_GET_STOP(serial_config);
/*
* only parity config is implemented, check if other serial settings
* are the default one.
*/
if (bits != SERIAL_8_BITS || stop != SERIAL_ONE_STOP)
return -ENOTSUPP; /* not supported in driver*/
switch (parity) {
case SERIAL_PAR_NONE:
/* no bits to add */
break;
case SERIAL_PAR_ODD:
lcr_val |= UART_LCR_PEN;
break;
case SERIAL_PAR_EVEN:
lcr_val |= UART_LCR_PEN | UART_LCR_EPS;
break;
default:
return -ENOTSUPP; /* not supported in driver*/
}
serial_out(lcr_val, &com_port->lcr);
return 0;
}
static int ns16550_serial_getinfo(struct udevice *dev,
struct serial_device_info *info)
{
struct NS16550 *const com_port = dev_get_priv(dev);
struct ns16550_platdata *plat = com_port->plat;
info->type = SERIAL_CHIP_16550_COMPATIBLE;
#ifdef CONFIG_SYS_NS16550_PORT_MAPPED
info->addr_space = SERIAL_ADDRESS_SPACE_IO;
#else
info->addr_space = SERIAL_ADDRESS_SPACE_MEMORY;
#endif
info->addr = plat->base;
info->reg_width = plat->reg_width;
info->reg_shift = plat->reg_shift;
info->reg_offset = plat->reg_offset;
return 0;
}
int ns16550_serial_probe(struct udevice *dev)
{
struct NS16550 *const com_port = dev_get_priv(dev);
struct reset_ctl_bulk reset_bulk;
int ret;
ret = reset_get_bulk(dev, &reset_bulk);
if (!ret)
reset_deassert_bulk(&reset_bulk);
com_port->plat = dev_get_platdata(dev);
NS16550_init(com_port, -1);
return 0;
}
#if CONFIG_IS_ENABLED(OF_CONTROL)
enum {
PORT_NS16550 = 0,
PORT_JZ4780,
};
#endif
#if CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA)
int ns16550_serial_ofdata_to_platdata(struct udevice *dev)
{
struct ns16550_platdata *plat = dev->platdata;
const u32 port_type = dev_get_driver_data(dev);
fdt_addr_t addr;
struct clk clk;
int err;
/* try Processor Local Bus device first */
addr = dev_read_addr(dev);
#if CONFIG_IS_ENABLED(PCI) && defined(CONFIG_DM_PCI)
if (addr == FDT_ADDR_T_NONE) {
/* then try pci device */
struct fdt_pci_addr pci_addr;
u32 bar;
int ret;
/* we prefer to use a memory-mapped register */
ret = fdtdec_get_pci_addr(gd->fdt_blob, dev_of_offset(dev),
FDT_PCI_SPACE_MEM32, "reg",
&pci_addr);
if (ret) {
/* try if there is any i/o-mapped register */
ret = fdtdec_get_pci_addr(gd->fdt_blob,
dev_of_offset(dev),
FDT_PCI_SPACE_IO,
"reg", &pci_addr);
if (ret)
return ret;
}
ret = fdtdec_get_pci_bar32(dev, &pci_addr, &bar);
if (ret)
return ret;
addr = bar;
}
#endif
if (addr == FDT_ADDR_T_NONE)
return -EINVAL;
#ifdef CONFIG_SYS_NS16550_PORT_MAPPED
plat->base = addr;
#else
plat->base = (unsigned long)map_physmem(addr, 0, MAP_NOCACHE);
#endif
plat->reg_offset = dev_read_u32_default(dev, "reg-offset", 0);
plat->reg_shift = dev_read_u32_default(dev, "reg-shift", 0);
plat->reg_width = dev_read_u32_default(dev, "reg-io-width", 1);
err = clk_get_by_index(dev, 0, &clk);
if (!err) {
err = clk_get_rate(&clk);
if (!IS_ERR_VALUE(err))
plat->clock = err;
} else if (err != -ENOENT && err != -ENODEV && err != -ENOSYS) {
debug("ns16550 failed to get clock\n");
return err;
}
if (!plat->clock)
plat->clock = dev_read_u32_default(dev, "clock-frequency",
CONFIG_SYS_NS16550_CLK);
if (!plat->clock) {
debug("ns16550 clock not defined\n");
return -EINVAL;
}
plat->fcr = UART_FCR_DEFVAL;
if (port_type == PORT_JZ4780)
plat->fcr |= UART_FCR_UME;
return 0;
}
#endif
const struct dm_serial_ops ns16550_serial_ops = {
.putc = ns16550_serial_putc,
.pending = ns16550_serial_pending,
.getc = ns16550_serial_getc,
.setbrg = ns16550_serial_setbrg,
.setconfig = ns16550_serial_setconfig,
.getinfo = ns16550_serial_getinfo,
};
#if CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA)
/*
* Please consider existing compatible strings before adding a new
* one to keep this table compact. Or you may add a generic "ns16550"
* compatible string to your dts.
*/
static const struct udevice_id ns16550_serial_ids[] = {
{ .compatible = "ns16550", .data = PORT_NS16550 },
{ .compatible = "ns16550a", .data = PORT_NS16550 },
{ .compatible = "ingenic,jz4780-uart", .data = PORT_JZ4780 },
{ .compatible = "nvidia,tegra20-uart", .data = PORT_NS16550 },
{ .compatible = "snps,dw-apb-uart", .data = PORT_NS16550 },
{}
};
#endif /* OF_CONTROL && !OF_PLATDATA */
#if CONFIG_IS_ENABLED(SERIAL_PRESENT)
/* TODO(sjg@chromium.org): Integrate this into a macro like CONFIG_IS_ENABLED */
#if !defined(CONFIG_TPL_BUILD) || defined(CONFIG_TPL_DM_SERIAL)
U_BOOT_DRIVER(ns16550_serial) = {
.name = "ns16550_serial",
.id = UCLASS_SERIAL,
#if CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA)
.of_match = ns16550_serial_ids,
.ofdata_to_platdata = ns16550_serial_ofdata_to_platdata,
.platdata_auto_alloc_size = sizeof(struct ns16550_platdata),
#endif
.priv_auto_alloc_size = sizeof(struct NS16550),
.probe = ns16550_serial_probe,
.ops = &ns16550_serial_ops,
#if !CONFIG_IS_ENABLED(OF_CONTROL)
.flags = DM_FLAG_PRE_RELOC,
#endif
};
#endif
#endif /* SERIAL_PRESENT */
#endif /* CONFIG_DM_SERIAL */
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