+++ /dev/null
-From 081a639e9274072fbd34ee778188332ed972734e Mon Sep 17 00:00:00 2001
-From: Andy Green <andy@openmoko.com>
-Date: Fri, 25 Jul 2008 23:06:16 +0100
-Subject: [PATCH] introduce-resume-exception-capture.patch
-
-This patch introduces a new resume debugging concept: if we
-get an OOPS inbetween starting suspend and finishing resume, it
-uses a new "emergency spew" device similar to BUT NOT REQUIRING
-CONFIG_DEBUG_LL to dump the syslog buffer and then the OOPS
-on the debug device defined by the existing CONFIG_DEBUG_S3C_UART
-index. But neither CONFIG_DEBUG_LL nor the S3C low level configs
-are needed to use this feature.
-
-Another difference between this feature and CONFIG_DEBUG_LL is that
-it does not affect resume timing, ordering or UART traffic UNLESS
-there is an OOPS during resume.
-
-The patch adds three global exports, one to say if we are inside
-suspend / resume, and two callbacks for printk() to use to init
-and dump the emergency data. The callbacks are set in s3c serial
-device init, but the whole structure is arch independent.
-
-Signed-off-by: Andy Green <andy@openmoko.com>
----
- drivers/serial/s3c2410.c | 77 +++++++++++++++++++++++++++++++++++++++++++++-
- include/linux/kernel.h | 2 +
- include/linux/suspend.h | 6 +++
- kernel/power/main.c | 7 ++++
- kernel/printk.c | 42 +++++++++++++++++++++++++
- 5 files changed, 133 insertions(+), 1 deletions(-)
-
-diff --git a/drivers/serial/s3c2410.c b/drivers/serial/s3c2410.c
-index 32cceae..f20f63b 100644
---- a/drivers/serial/s3c2410.c
-+++ b/drivers/serial/s3c2410.c
-@@ -81,6 +81,7 @@
-
- #include <asm/plat-s3c/regs-serial.h>
- #include <asm/arch/regs-gpio.h>
-+#include <asm/arch/regs-clock.h>
-
- /* structures */
-
-@@ -1170,7 +1171,13 @@ static int s3c24xx_serial_init(struct platform_driver *drv,
- struct s3c24xx_uart_info *info)
- {
- dbg("s3c24xx_serial_init(%p,%p)\n", drv, info);
-- return platform_driver_register(drv);
-+ /* set up the emergency debug UART functions */
-+
-+ printk_emergency_debug_spew_init = s3c24xx_serial_force_debug_port_up;
-+ printk_emergency_debug_spew_send_string = s3c2410_printascii;
-+
-+ dbg("s3c24xx_serial_init(%p,%p)\n", drv, info);
-+ return platform_driver_register(drv);
- }
-
-
-@@ -1647,6 +1654,74 @@ static struct platform_driver s3c2412_serial_drv = {
- },
- };
-
-+static void s3c24xx_serial_force_debug_port_up(void)
-+{
-+ struct s3c24xx_uart_port *ourport = &s3c24xx_serial_ports[
-+ CONFIG_DEBUG_S3C_UART];
-+ struct s3c24xx_uart_clksrc *clksrc = NULL;
-+ struct clk *clk = NULL;
-+ unsigned long tmp;
-+
-+ s3c24xx_serial_getclk(&ourport->port, &clksrc, &clk, 115200);
-+
-+ tmp = __raw_readl(S3C2410_CLKCON);
-+
-+ /* re-start uart clocks */
-+ tmp |= S3C2410_CLKCON_UART0;
-+ tmp |= S3C2410_CLKCON_UART1;
-+ tmp |= S3C2410_CLKCON_UART2;
-+
-+ __raw_writel(tmp, S3C2410_CLKCON);
-+ udelay(10);
-+
-+ s3c24xx_serial_setsource(&ourport->port, clksrc);
-+
-+ if (ourport->baudclk != NULL && !IS_ERR(ourport->baudclk)) {
-+ clk_disable(ourport->baudclk);
-+ ourport->baudclk = NULL;
-+ }
-+
-+ clk_enable(clk);
-+
-+ ourport->clksrc = clksrc;
-+ ourport->baudclk = clk;
-+}
-+
-+static void s3c2410_printascii(const char *sz)
-+{
-+ struct s3c24xx_uart_port *ourport = &s3c24xx_serial_ports[
-+ CONFIG_DEBUG_S3C_UART];
-+ struct uart_port *port = &ourport->port;
-+
-+ /* 8 N 1 */
-+ wr_regl(port, S3C2410_ULCON, (rd_regl(port, S3C2410_ULCON)) | 3);
-+ /* polling mode */
-+ wr_regl(port, S3C2410_UCON, (rd_regl(port, S3C2410_UCON) & ~0xc0f) | 5);
-+ /* disable FIFO */
-+ wr_regl(port, S3C2410_UFCON, (rd_regl(port, S3C2410_UFCON) & ~0x01));
-+ /* fix baud rate */
-+ wr_regl(port, S3C2410_UBRDIV, 26);
-+
-+ while (*sz) {
-+ int timeout = 10000000;
-+
-+ /* spin on it being busy */
-+ while ((!(rd_regl(port, S3C2410_UTRSTAT) & 2)) && timeout--)
-+ ;
-+
-+ /* transmit register */
-+ wr_regl(port, S3C2410_UTXH, *sz);
-+
-+ sz++;
-+ }
-+}
-+
-+
-+/* s3c24xx_serial_resetport
-+ *
-+ * wrapper to call the specific reset for this port (reset the fifos
-+ * and the settings)
-+*/
-
- static inline int s3c2412_serial_init(void)
- {
-diff --git a/include/linux/kernel.h b/include/linux/kernel.h
-index 2e70006..fcad89e 100644
---- a/include/linux/kernel.h
-+++ b/include/linux/kernel.h
-@@ -198,6 +198,8 @@ extern int __ratelimit(int ratelimit_jiffies, int ratelimit_burst);
- extern int __printk_ratelimit(int ratelimit_jiffies, int ratelimit_burst);
- extern bool printk_timed_ratelimit(unsigned long *caller_jiffies,
- unsigned int interval_msec);
-+extern void (*printk_emergency_debug_spew_init)(void);
-+extern void (*printk_emergency_debug_spew_send_string)(const char *);
- #else
- static inline int vprintk(const char *s, va_list args)
- __attribute__ ((format (printf, 1, 0)));
-diff --git a/include/linux/suspend.h b/include/linux/suspend.h
-index a697742..8164615 100644
---- a/include/linux/suspend.h
-+++ b/include/linux/suspend.h
-@@ -140,6 +140,12 @@ struct pbe {
- struct pbe *next;
- };
-
-+/**
-+ * global indication we are somewhere between start of suspend and end of
-+ * resume, nonzero is true
-+ */
-+extern int global_inside_suspend;
-+
- /* mm/page_alloc.c */
- extern void mark_free_pages(struct zone *zone);
-
-diff --git a/kernel/power/main.c b/kernel/power/main.c
-index 6a6d5eb..1169648 100644
---- a/kernel/power/main.c
-+++ b/kernel/power/main.c
-@@ -130,6 +130,9 @@ static inline int suspend_test(int level) { return 0; }
-
- #endif /* CONFIG_PM_SLEEP */
-
-+int global_inside_suspend;
-+EXPORT_SYMBOL(global_inside_suspend);
-+
- #ifdef CONFIG_SUSPEND
-
- /* This is just an arbitrary number */
-@@ -258,6 +261,8 @@ int suspend_devices_and_enter(suspend_state_t state)
- if (!suspend_ops)
- return -ENOSYS;
-
-+ global_inside_suspend = 1;
-+
- if (suspend_ops->begin) {
- error = suspend_ops->begin(state);
- if (error)
-@@ -297,6 +302,8 @@ int suspend_devices_and_enter(suspend_state_t state)
- Close:
- if (suspend_ops->end)
- suspend_ops->end();
-+ global_inside_suspend = 0;
-+
- return error;
- }
-
-diff --git a/kernel/printk.c b/kernel/printk.c
-index e2129e8..00df30e 100644
---- a/kernel/printk.c
-+++ b/kernel/printk.c
-@@ -32,8 +32,12 @@
- #include <linux/security.h>
- #include <linux/bootmem.h>
- #include <linux/syscalls.h>
-+#include <linux/jiffies.h>
-+#include <linux/suspend.h>
-
- #include <asm/uaccess.h>
-+#include <asm/plat-s3c24xx/neo1973.h>
-+#include <asm/arch/gta02.h>
-
- /*
- * Architectures can override it:
-@@ -67,6 +71,12 @@ int console_printk[4] = {
- int oops_in_progress;
- EXPORT_SYMBOL(oops_in_progress);
-
-+void (*printk_emergency_debug_spew_init)(void) = NULL;
-+EXPORT_SYMBOL(printk_emergency_debug_spew_init);
-+
-+void (*printk_emergency_debug_spew_send_string)(const char *) = NULL;
-+EXPORT_SYMBOL(printk_emergency_debug_spew_send_string);
-+
- /*
- * console_sem protects the console_drivers list, and also
- * provides serialisation for access to the entire console
-@@ -718,6 +728,38 @@ asmlinkage int vprintk(const char *fmt, va_list args)
- printed_len += vscnprintf(printk_buf + printed_len,
- sizeof(printk_buf) - printed_len, fmt, args);
-
-+ /* if you're debugging resume, the normal methods can change resume
-+ * ordering behaviours because their debugging output is synchronous
-+ * (ie, CONFIG_DEBUG_LL). If your problem is an OOPS, this code
-+ * will not affect the speed and duration and ordering of resume
-+ * actions, but will give you a chance to read the full undumped
-+ * syslog AND the OOPS data when it happens
-+ *
-+ * if you support it, your debug device init can override the exported
-+ * emergency_debug_spew_init and emergency_debug_spew_send_string to
-+ * usually force polling or bitbanging on your debug console device
-+ */
-+ if (oops_in_progress && global_inside_suspend &&
-+ printk_emergency_debug_spew_init &&
-+ printk_emergency_debug_spew_send_string) {
-+ unsigned long cur_index;
-+ char ch[2];
-+
-+ if (global_inside_suspend == 1) {
-+ (printk_emergency_debug_spew_init)();
-+
-+ ch[1] = '\0';
-+ cur_index = con_start;
-+ while (cur_index != log_end) {
-+ ch[0] = LOG_BUF(cur_index);
-+ (printk_emergency_debug_spew_send_string)(ch);
-+ cur_index++;
-+ }
-+ global_inside_suspend++; /* only once */
-+ }
-+ (printk_emergency_debug_spew_send_string)(printk_buf);
-+ }
-+
- /*
- * Copy the output into log_buf. If the caller didn't provide
- * appropriate log level tags, we insert them here
---
-1.5.6.3
-
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