[ARM PATCH] 2208/1: S3C2410 - pm updates and fixes

Patch from Ben Dooks

This fixes the following with s3c24xx power management:

- debugging needs UARTs enabled, to re-enabled UART clocks,
  save their state over suspend, and add this to the current
  documentation

- update the documentation on pm initialisation

- fix bug reported by Dimitry Andric where __raw_writel()
  has arguments the wrong way around

- fix typo (lower-case letter in S3C2410_GATSTUs2_OFFRESET)
  from Dimitry Andric

- apply Arnaud Patard's patch for pm call types

- move bits of resume code to use printk(KERN_DEBUG) as they
  are potentially before the UART resume, and are not critical
  if the system fails to re-start.

Signed-off-by: Ben Dooks 
Signed-off-by: Russell King

Documentation/arm/Samsung-S3C24XX/Suspend.txt

@@ -33,7 +33,8 @@ Resuming
   code to resume Linux operation.
 
   GSTATUS4 is currently left alone by the sleep code, and is free to
-  use for any other purposes.
+  use for any other purposes (for example, the EB2410ITX uses this to
+  save memory configuration in).
 
 
 Machine Support
@@ -41,9 +42,9 @@ Machine Support
 
   The machine specific functions must call the s3c2410_pm_init() function
   to say that it's bootloader is capable of resuming. This can be as
-  simple as adding the following to the file:
+  simple as adding the following to the machine's definition:
 
-  late_initcall(s3c2410_pm_init);
+  INITMACHINE(s3c2410_pm_init)
 
   A board can do its own setup before calling s3c2410_pm_init, if it
   needs to setup anything else for power management support.
@@ -52,6 +53,23 @@ Machine Support
   saving the resume address, if your board requires it, then contact
   the maintainer and discuss what is required.
 
+  Note, the origianal method of adding an late_initcall() is wrong,
+  and will end up initialising all compiled machine's pm init!
+
+
+Debugging
+---------
+
+  There are several important things to rember when using PM suspend:
+
+  1) The uart drivers will disable the clocks to the UART blocks when
+     suspending, which means that use of printascii() or similar direct
+     access to the UARTs will cause the debug to stop.
+
+  2) Whilst the pm code itself will attempt to re-enabled the UART clocks,
+     care should be taken that any external clock sources that the UARTs
+     rely on are still enabled at that point
+
 
 Configuration
 -------------

arch/arm/mach-s3c2410/pm.c

@@ -23,6 +23,7 @@
  *
  * Parts based on arch/arm/mach-pxa/pm.c
  *
+ * Thanks to Dimitry Andric for debugging
 */
 
 #include <linux/config.h>
@@ -33,10 +34,12 @@
 #include <linux/interrupt.h>
 #include <linux/crc32.h>
 #include <linux/ioport.h>
+#include <linux/delay.h>
 
 #include <asm/hardware.h>
 #include <asm/io.h>
 
+#include <asm/arch/regs-serial.h>
 #include <asm/arch/regs-clock.h>
 #include <asm/arch/regs-gpio.h>
 #include <asm/arch/regs-mem.h>
@@ -68,7 +71,21 @@ struct sleep_save {
 
 static struct sleep_save core_save[] = {
 	SAVE_ITEM(S3C2410_LOCKTIME),
-	SAVE_ITEM(S3C2410_CLKCON)
+	SAVE_ITEM(S3C2410_CLKCON),
+
+	/* we restore the timings here, with the proviso that the board
+	 * brings the system up in an slower, or equal frequency setting
+	 * to the original system.
+	 *
+	 * if we cannot guarantee this, then things are going to go very
+	 * wrong here, as we modify the refresh and both pll settings.
+	 */
+
+	SAVE_ITEM(S3C2410_REFRESH),
+	SAVE_ITEM(S3C2410_MPLLCON),
+	SAVE_ITEM(S3C2410_UPLLCON),
+	SAVE_ITEM(S3C2410_CLKDIVN),
+	SAVE_ITEM(S3C2410_CLKSLOW),
 };
 
 /* this lot should be really saved by the IRQ code */
@@ -115,6 +132,20 @@ static struct sleep_save gpio_save[] = {
 };
 
 #ifdef CONFIG_S3C2410_PM_DEBUG
+
+#define SAVE_UART(va) \
+	SAVE_ITEM((va) + S3C2410_ULCON), \
+	SAVE_ITEM((va) + S3C2410_UCON), \
+	SAVE_ITEM((va) + S3C2410_UFCON), \
+	SAVE_ITEM((va) + S3C2410_UMCON), \
+	SAVE_ITEM((va) + S3C2410_UBRDIV)
+
+static struct sleep_save uart_save[] = {
+	SAVE_UART(S3C2410_VA_UART0),
+	SAVE_UART(S3C2410_VA_UART1),
+	SAVE_UART(S3C2410_VA_UART2),
+};
+
 /* debug
  *
  * we send the debug to printascii() to allow it to be seen if the
@@ -135,10 +166,24 @@ static void pm_dbg(const char *fmt, ...)
 	printascii(buff);
 }
 
+static void s3c2410_pm_debug_init(void)
+{
+	unsigned long 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);
+}
 
 #define DBG(fmt...) pm_dbg(fmt)
 #else
 #define DBG(fmt...) printk(KERN_DEBUG fmt)
+
+#define s3c2410_pm_debug_init() do { } while(0)
 #endif
 
 #if defined(CONFIG_S3C2410_PM_CHECK) && CONFIG_S3C2410_PM_CHECK_CHUNKSIZE != 0
@@ -329,6 +374,9 @@ static void s3c2410_pm_check_restore(void)
 }
 
 #else
+
+static struct sleep_save uart_save[] = {};
+
 #define s3c2410_pm_check_prepare() do { } while(0)
 #define s3c2410_pm_check_restore() do { } while(0)
 #define s3c2410_pm_check_store()   do { } while(0)
@@ -344,12 +392,20 @@ static void s3c2410_pm_do_save(struct sleep_save *ptr, int count)
 	}
 }
 
+/* s3c2410_pm_do_restore
+ *
+ * restore the system from the given list of saved registers
+ *
+ * Note, we do not use DBG() in here, as the system may not have
+ * restore the UARTs state yet
+*/
 
 static void s3c2410_pm_do_restore(struct sleep_save *ptr, int count)
 {
 	for (; count > 0; count--, ptr++) {
-		DBG("restore %08lx (restore %08lx, current %08x)\n",
-		    ptr->reg, ptr->val, __raw_readl(ptr->reg));
+		printk(KERN_DEBUG "restore %08lx (restore %08lx, was %08x)\n",
+		       ptr->reg, ptr->val, __raw_readl(ptr->reg));
+
 		__raw_writel(ptr->val, ptr->reg);
 	}
 }
@@ -434,11 +490,15 @@ static void s3c2410_pm_configure_extint(void)
  * central control for sleep/resume process
 */
 
-static int s3c2410_pm_enter(u32 state)
+static int s3c2410_pm_enter(suspend_state_t state)
 {
 	unsigned long regs_save[16];
 	unsigned long tmp;
 
+	/* ensure the debug is initialised (if enabled) */
+
+	s3c2410_pm_debug_init();
+
 	DBG("s3c2410_pm_enter(%d)\n", state);
 
 	if (state != PM_SUSPEND_MEM) {
@@ -480,6 +540,7 @@ static int s3c2410_pm_enter(u32 state)
 	s3c2410_pm_do_save(gpio_save, ARRAY_SIZE(gpio_save));
 	s3c2410_pm_do_save(irq_save, ARRAY_SIZE(irq_save));
 	s3c2410_pm_do_save(core_save, ARRAY_SIZE(core_save));
+	s3c2410_pm_do_save(uart_save, ARRAY_SIZE(uart_save));
 
 	/* set the irq configuration for wake */
 
@@ -493,7 +554,7 @@ static int s3c2410_pm_enter(u32 state)
 
 	/* ack any outstanding external interrupts before we go to sleep */
 
-	__raw_writel(S3C2410_EINTPEND, __raw_readl(S3C2410_EINTPEND));
+	__raw_writel(__raw_readl(S3C2410_EINTPEND), S3C2410_EINTPEND);
 
 	/* flush cache back to ram */
 
@@ -512,9 +573,18 @@ static int s3c2410_pm_enter(u32 state)
 	/* unset the return-from-sleep flag, to ensure reset */
 
 	tmp = __raw_readl(S3C2410_GSTATUS2);
-	tmp &= S3C2410_GSTATUs2_OFFRESET;
+	tmp &= S3C2410_GSTATUS2_OFFRESET;
 	__raw_writel(tmp, S3C2410_GSTATUS2);
 
+	/* restore the system state */
+
+	s3c2410_pm_do_restore(core_save, ARRAY_SIZE(core_save));
+	s3c2410_pm_do_restore(gpio_save, ARRAY_SIZE(gpio_save));
+	s3c2410_pm_do_restore(irq_save, ARRAY_SIZE(irq_save));
+	s3c2410_pm_do_restore(uart_save, ARRAY_SIZE(uart_save));
+
+	s3c2410_pm_debug_init();
+
 	/* check what irq (if any) restored the system */
 
 	DBG("post sleep: IRQs 0x%08x, 0x%08x\n",
@@ -527,12 +597,6 @@ static int s3c2410_pm_enter(u32 state)
 	s3c2410_pm_show_resume_irqs(IRQ_EINT4-4, __raw_readl(S3C2410_EINTPEND),
 				    s3c_irqwake_eintmask);
 
-	DBG("post sleep, restoring state...\n");
-
-	s3c2410_pm_do_restore(core_save, ARRAY_SIZE(core_save));
-	s3c2410_pm_do_restore(gpio_save, ARRAY_SIZE(gpio_save));
-	s3c2410_pm_do_restore(irq_save, ARRAY_SIZE(irq_save));
-
 	DBG("post sleep, preparing to return\n");
 
 	s3c2410_pm_check_restore();
@@ -546,7 +610,7 @@ static int s3c2410_pm_enter(u32 state)
 /*
  * Called after processes are frozen, but before we shut down devices.
  */
-static int s3c2410_pm_prepare(u32 state)
+static int s3c2410_pm_prepare(suspend_state_t state)
 {
 	return 0;
 }
@@ -554,7 +618,7 @@ static int s3c2410_pm_prepare(u32 state)
 /*
  * Called after devices are re-setup, but before processes are thawed.
  */
-static int s3c2410_pm_finish(u32 state)
+static int s3c2410_pm_finish(suspend_state_t state)
 {
 	return 0;
 }

arch/arm/mach-s3c2410/sleep.S

@@ -35,7 +35,10 @@
 #include <asm/arch/regs-mem.h>
 #include <asm/arch/regs-serial.h>
 
-#define CONFIG_DEBUG_RESUME
+/* CONFIG_DEBUG_RESUME is dangerous if your bootloader does not
+ * reset the UART configuration, only enable if you really need this!
+*/
+//#define CONFIG_DEBUG_RESUME
 
 	.text
 
@@ -133,6 +136,15 @@ ENTRY(s3c2410_cpu_resume)
 	mov	r2, #S3C2410_PA_UART & 0xff000000
 	orr	r2, r2, #S3C2410_PA_UART & 0xff000
 
+#if 0
+	/* SMDK2440 LED set */
+	mov	r14, #S3C2410_PA_GPIO
+	ldr	r12, [ r14, #0x54 ]
+	bic	r12, r12, #3<<4
+	orr	r12, r12, #1<<7
+	str	r12, [ r14, #0x54 ]
+#endif
+
 #ifdef CONFIG_DEBUG_RESUME
 	mov	r3, #'L'
 	strb	r3, [ r2, #S3C2410_UTXH ]

include/asm-arm/arch-s3c2410/regs-gpio.h

@@ -812,7 +812,7 @@
 #define S3C2410_GSTATUS1_2440	   (0x32440000)
 
 #define S3C2410_GSTATUS2_WTRESET   (1<<2)
-#define S3C2410_GSTATUs2_OFFRESET  (1<<1)
+#define S3C2410_GSTATUS2_OFFRESET  (1<<1)
 #define S3C2410_GSTATUS2_PONRESET  (1<<0)
 
 #endif	/* __ASM_ARCH_REGS_GPIO_H */