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linux-next/arch/arm/mach-omap2/serial.c
Rajendra Nayak 7dedd34694 ARM: OMAP2+: hwmod: Fix a crash in _setup_reset() with DEBUG_LL
With commit '82702ea11ddfe0e43382e1fa5b66d807d8114916' "ARM: OMAP2+:
Fix serial init for device tree based booting" stubbing out
omap_serial_early_init() for Device tree based booting, there was a
crash observed on AM335x based devices when hwmod does a
_setup_reset() early at boot.

This was rootcaused to hwmod trying to reset console uart while
earlycon was using it.  The way to tell hwmod not to do this is to
specify the HWMOD_INIT_NO_RESET flag, which were infact set by the
omap_serial_early_init() function by parsing the cmdline to identify
the console device.

Parsing the cmdline to identify the uart used by earlycon itself seems
broken as there is nothing preventing earlycon to use a different one.

This patch, instead, attempts to populate the requiste flags for hwmod
based on the CONFIG_DEBUG_OMAPxUARTy FLAGS. This gets rid of the need
for cmdline parsing in the DT as well as non-DT cases to identify the
uart used by earlycon.

Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Reported-by: Mark Jackson <mpfj-list@newflow.co.uk>
Reported-by: Vaibhav Bedia <vaibhav.bedia@ti.com>
Tested-by: Mark Jackson <mpfj-list@newflow.co.uk>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
2013-07-30 05:13:35 -06:00

336 lines
9.0 KiB
C

/*
* arch/arm/mach-omap2/serial.c
*
* OMAP2 serial support.
*
* Copyright (C) 2005-2008 Nokia Corporation
* Author: Paul Mundt <paul.mundt@nokia.com>
*
* Major rework for PM support by Kevin Hilman
*
* Based off of arch/arm/mach-omap/omap1/serial.c
*
* Copyright (C) 2009 Texas Instruments
* Added OMAP4 support - Santosh Shilimkar <santosh.shilimkar@ti.com
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/pm_runtime.h>
#include <linux/console.h>
#include <linux/omap-dma.h>
#include <linux/platform_data/serial-omap.h>
#include "common.h"
#include "omap_hwmod.h"
#include "omap_device.h"
#include "omap-pm.h"
#include "soc.h"
#include "prm2xxx_3xxx.h"
#include "pm.h"
#include "cm2xxx_3xxx.h"
#include "prm-regbits-34xx.h"
#include "control.h"
#include "mux.h"
#include "serial.h"
/*
* NOTE: By default the serial auto_suspend timeout is disabled as it causes
* lost characters over the serial ports. This means that the UART clocks will
* stay on until power/autosuspend_delay is set for the uart from sysfs.
* This also causes that any deeper omap sleep states are blocked.
*/
#define DEFAULT_AUTOSUSPEND_DELAY -1
#define MAX_UART_HWMOD_NAME_LEN 16
struct omap_uart_state {
int num;
struct list_head node;
struct omap_hwmod *oh;
struct omap_device_pad default_omap_uart_pads[2];
};
static LIST_HEAD(uart_list);
static u8 num_uarts;
static u8 console_uart_id = -1;
static u8 uart_debug;
#define DEFAULT_RXDMA_POLLRATE 1 /* RX DMA polling rate (us) */
#define DEFAULT_RXDMA_BUFSIZE 4096 /* RX DMA buffer size */
#define DEFAULT_RXDMA_TIMEOUT (3 * HZ)/* RX DMA timeout (jiffies) */
static struct omap_uart_port_info omap_serial_default_info[] __initdata = {
{
.dma_enabled = false,
.dma_rx_buf_size = DEFAULT_RXDMA_BUFSIZE,
.dma_rx_poll_rate = DEFAULT_RXDMA_POLLRATE,
.dma_rx_timeout = DEFAULT_RXDMA_TIMEOUT,
.autosuspend_timeout = DEFAULT_AUTOSUSPEND_DELAY,
},
};
#ifdef CONFIG_PM
static void omap_uart_enable_wakeup(struct device *dev, bool enable)
{
struct platform_device *pdev = to_platform_device(dev);
struct omap_device *od = to_omap_device(pdev);
if (!od)
return;
if (enable)
omap_hwmod_enable_wakeup(od->hwmods[0]);
else
omap_hwmod_disable_wakeup(od->hwmods[0]);
}
#else
static void omap_uart_enable_wakeup(struct device *dev, bool enable)
{}
#endif /* CONFIG_PM */
#ifdef CONFIG_OMAP_MUX
#define OMAP_UART_DEFAULT_PAD_NAME_LEN 28
static char rx_pad_name[OMAP_UART_DEFAULT_PAD_NAME_LEN],
tx_pad_name[OMAP_UART_DEFAULT_PAD_NAME_LEN] __initdata;
static void __init
omap_serial_fill_uart_tx_rx_pads(struct omap_board_data *bdata,
struct omap_uart_state *uart)
{
uart->default_omap_uart_pads[0].name = rx_pad_name;
uart->default_omap_uart_pads[0].flags = OMAP_DEVICE_PAD_REMUX |
OMAP_DEVICE_PAD_WAKEUP;
uart->default_omap_uart_pads[0].enable = OMAP_PIN_INPUT |
OMAP_MUX_MODE0;
uart->default_omap_uart_pads[0].idle = OMAP_PIN_INPUT | OMAP_MUX_MODE0;
uart->default_omap_uart_pads[1].name = tx_pad_name;
uart->default_omap_uart_pads[1].enable = OMAP_PIN_OUTPUT |
OMAP_MUX_MODE0;
bdata->pads = uart->default_omap_uart_pads;
bdata->pads_cnt = ARRAY_SIZE(uart->default_omap_uart_pads);
}
static void __init omap_serial_check_wakeup(struct omap_board_data *bdata,
struct omap_uart_state *uart)
{
struct omap_mux_partition *tx_partition = NULL, *rx_partition = NULL;
struct omap_mux *rx_mux = NULL, *tx_mux = NULL;
char *rx_fmt, *tx_fmt;
int uart_nr = bdata->id + 1;
if (bdata->id != 2) {
rx_fmt = "uart%d_rx.uart%d_rx";
tx_fmt = "uart%d_tx.uart%d_tx";
} else {
rx_fmt = "uart%d_rx_irrx.uart%d_rx_irrx";
tx_fmt = "uart%d_tx_irtx.uart%d_tx_irtx";
}
snprintf(rx_pad_name, OMAP_UART_DEFAULT_PAD_NAME_LEN, rx_fmt,
uart_nr, uart_nr);
snprintf(tx_pad_name, OMAP_UART_DEFAULT_PAD_NAME_LEN, tx_fmt,
uart_nr, uart_nr);
if (omap_mux_get_by_name(rx_pad_name, &rx_partition, &rx_mux) >= 0 &&
omap_mux_get_by_name
(tx_pad_name, &tx_partition, &tx_mux) >= 0) {
u16 tx_mode, rx_mode;
tx_mode = omap_mux_read(tx_partition, tx_mux->reg_offset);
rx_mode = omap_mux_read(rx_partition, rx_mux->reg_offset);
/*
* Check if uart is used in default tx/rx mode i.e. in mux mode0
* if yes then configure rx pin for wake up capability
*/
if (OMAP_MODE_UART(rx_mode) && OMAP_MODE_UART(tx_mode))
omap_serial_fill_uart_tx_rx_pads(bdata, uart);
}
}
#else
static void __init omap_serial_check_wakeup(struct omap_board_data *bdata,
struct omap_uart_state *uart)
{
}
#endif
static char *cmdline_find_option(char *str)
{
extern char *saved_command_line;
return strstr(saved_command_line, str);
}
static int __init omap_serial_early_init(void)
{
if (of_have_populated_dt())
return -ENODEV;
do {
char oh_name[MAX_UART_HWMOD_NAME_LEN];
struct omap_hwmod *oh;
struct omap_uart_state *uart;
char uart_name[MAX_UART_HWMOD_NAME_LEN];
snprintf(oh_name, MAX_UART_HWMOD_NAME_LEN,
"uart%d", num_uarts + 1);
oh = omap_hwmod_lookup(oh_name);
if (!oh)
break;
uart = kzalloc(sizeof(struct omap_uart_state), GFP_KERNEL);
if (WARN_ON(!uart))
return -ENODEV;
uart->oh = oh;
uart->num = num_uarts++;
list_add_tail(&uart->node, &uart_list);
snprintf(uart_name, MAX_UART_HWMOD_NAME_LEN,
"%s%d", OMAP_SERIAL_NAME, uart->num);
if (cmdline_find_option(uart_name)) {
console_uart_id = uart->num;
if (console_loglevel >= 10) {
uart_debug = true;
pr_info("%s used as console in debug mode: uart%d clocks will not be gated",
uart_name, uart->num);
}
}
} while (1);
return 0;
}
omap_core_initcall(omap_serial_early_init);
/**
* omap_serial_init_port() - initialize single serial port
* @bdata: port specific board data pointer
* @info: platform specific data pointer
*
* This function initialies serial driver for given port only.
* Platforms can call this function instead of omap_serial_init()
* if they don't plan to use all available UARTs as serial ports.
*
* Don't mix calls to omap_serial_init_port() and omap_serial_init(),
* use only one of the two.
*/
void __init omap_serial_init_port(struct omap_board_data *bdata,
struct omap_uart_port_info *info)
{
struct omap_uart_state *uart;
struct omap_hwmod *oh;
struct platform_device *pdev;
void *pdata = NULL;
u32 pdata_size = 0;
char *name;
struct omap_uart_port_info omap_up;
if (WARN_ON(!bdata))
return;
if (WARN_ON(bdata->id < 0))
return;
if (WARN_ON(bdata->id >= num_uarts))
return;
list_for_each_entry(uart, &uart_list, node)
if (bdata->id == uart->num)
break;
if (!info)
info = omap_serial_default_info;
oh = uart->oh;
name = DRIVER_NAME;
omap_up.dma_enabled = info->dma_enabled;
omap_up.uartclk = OMAP24XX_BASE_BAUD * 16;
omap_up.flags = UPF_BOOT_AUTOCONF;
omap_up.get_context_loss_count = omap_pm_get_dev_context_loss_count;
omap_up.enable_wakeup = omap_uart_enable_wakeup;
omap_up.dma_rx_buf_size = info->dma_rx_buf_size;
omap_up.dma_rx_timeout = info->dma_rx_timeout;
omap_up.dma_rx_poll_rate = info->dma_rx_poll_rate;
omap_up.autosuspend_timeout = info->autosuspend_timeout;
omap_up.DTR_gpio = info->DTR_gpio;
omap_up.DTR_inverted = info->DTR_inverted;
omap_up.DTR_present = info->DTR_present;
pdata = &omap_up;
pdata_size = sizeof(struct omap_uart_port_info);
if (WARN_ON(!oh))
return;
pdev = omap_device_build(name, uart->num, oh, pdata, pdata_size);
if (IS_ERR(pdev)) {
WARN(1, "Could not build omap_device for %s: %s.\n", name,
oh->name);
return;
}
oh->mux = omap_hwmod_mux_init(bdata->pads, bdata->pads_cnt);
if (console_uart_id == bdata->id) {
omap_device_enable(pdev);
pm_runtime_set_active(&pdev->dev);
}
oh->dev_attr = uart;
if (((cpu_is_omap34xx() || cpu_is_omap44xx()) && bdata->pads)
&& !uart_debug)
device_init_wakeup(&pdev->dev, true);
}
/**
* omap_serial_board_init() - initialize all supported serial ports
* @info: platform specific data pointer
*
* Initializes all available UARTs as serial ports. Platforms
* can call this function when they want to have default behaviour
* for serial ports (e.g initialize them all as serial ports).
*/
void __init omap_serial_board_init(struct omap_uart_port_info *info)
{
struct omap_uart_state *uart;
struct omap_board_data bdata;
list_for_each_entry(uart, &uart_list, node) {
bdata.id = uart->num;
bdata.flags = 0;
bdata.pads = NULL;
bdata.pads_cnt = 0;
omap_serial_check_wakeup(&bdata, uart);
if (!info)
omap_serial_init_port(&bdata, NULL);
else
omap_serial_init_port(&bdata, &info[uart->num]);
}
}
/**
* omap_serial_init() - initialize all supported serial ports
*
* Initializes all available UARTs.
* Platforms can call this function when they want to have default behaviour
* for serial ports (e.g initialize them all as serial ports).
*/
void __init omap_serial_init(void)
{
omap_serial_board_init(NULL);
}