Re: [PATCH] OLPC: Add XO-1 suspend/resume support

[Randy Dunlap]

On Tue, 19 Oct 2010 23:01:58 +0100 (BST) Daniel Drake wrote:

> Add code needed for basic suspend/resume of the XO-1 laptop.
> 
> swsusp_pg_dir needs to be exposed as it is used by the assembly
> code run in the wakeup path.
> 
> Signed-off-by: Daniel Drake <dsd@xxxxxxxxxx>
> ---
>  arch/x86/include/asm/olpc.h       |    5 +-
>  arch/x86/kernel/Makefile          |    2 +-
>  arch/x86/kernel/olpc-xo1-wakeup.S |  132 +++++++++++++++++++++++++++++++++++++
>  arch/x86/kernel/olpc-xo1.c        |   79 ++++++++++++++++++++++
>  arch/x86/mm/init_32.c             |    6 +-
>  5 files changed, 219 insertions(+), 5 deletions(-)
>  create mode 100644 arch/x86/kernel/olpc-xo1-wakeup.S
> 
> diff --git a/arch/x86/include/asm/olpc.h b/arch/x86/include/asm/olpc.h
> index 101229b..54dfe92 100644
> --- a/arch/x86/include/asm/olpc.h
> +++ b/arch/x86/include/asm/olpc.h
> @@ -88,7 +88,10 @@ extern int olpc_ec_mask_unset(uint8_t bits);
>  
>  /* EC commands */
>  
> -#define EC_FIRMWARE_REV		0x08
> +#define EC_FIRMWARE_REV			0x08
> +#define EC_WAKE_UP_WLAN			0x24
> +#define EC_SET_SCI_INHIBIT		0x32
> +#define EC_SET_SCI_INHIBIT_RELEASE	0x34
>  
>  /* SCI source values */
>  
> diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
> index 4983b61..1b23334 100644
> --- a/arch/x86/kernel/Makefile
> +++ b/arch/x86/kernel/Makefile
> @@ -106,7 +106,7 @@ obj-$(CONFIG_SCx200)		+= scx200.o
>  scx200-y			+= scx200_32.o
>  
>  obj-$(CONFIG_OLPC)		+= olpc.o
> -obj-$(CONFIG_OLPC_XO1)		+= olpc-xo1.o
> +obj-$(CONFIG_OLPC_XO1)		+= olpc-xo1.o olpc-xo1-wakeup.o
>  obj-$(CONFIG_OLPC_OPENFIRMWARE)	+= olpc_ofw.o
>  obj-$(CONFIG_X86_MRST)		+= mrst.o
>  

Hi,
Does this build OK when CONFIG_PM is not enabled?
or is that config not possible?


> diff --git a/arch/x86/kernel/olpc-xo1-wakeup.S b/arch/x86/kernel/olpc-xo1-wakeup.S
> new file mode 100644
> index 0000000..d335074
> --- /dev/null
> +++ b/arch/x86/kernel/olpc-xo1-wakeup.S
> @@ -0,0 +1,132 @@
> +.text
> +#include <linux/linkage.h>
> +#include <asm/segment.h>
> +#include <asm/page.h>
> +
> +	.macro writepost,value
> +		movb $0x34, %al
> +		outb %al, $0x70
> +		movb $\value, %al
> +		outb %al, $0x71
> +	.endm
> +
> +ALIGN
> +	.align 4096
> +
> +wakeup_start:
> +#	jmp wakeup_start
> +
> +	cli
> +	cld
> +
> +	# Clear any dangerous flags
> +
> +	pushl $0
> +	popfl
> +
> +	writepost 0x31
> +
> +	# Set up %cr3
> +	movl $swsusp_pg_dir - __PAGE_OFFSET, %eax
> +	movl %eax, %cr3
> +
> +	movl saved_cr4, %eax
> +	movl %eax, %cr4
> +
> +	movl saved_cr0, %eax
> +	movl %eax, %cr0
> +
> +	jmp 1f
> +1:
> +	ljmpl $__KERNEL_CS,$wakeup_return
> +
> +
> +.org 0x1000
> +
> +wakeup_return:
> +	movw    $__KERNEL_DS, %ax
> +	movw    %ax, %ss
> +	movw    %ax, %ds
> +	movw    %ax, %es
> +	movw    %ax, %fs
> +	movw    %ax, %gs
> +
> +	lgdt    saved_gdt
> +	lidt    saved_idt
> +	lldt    saved_ldt
> +	ljmp    $(__KERNEL_CS),$1f
> +1:
> +	movl    %cr3, %eax
> +	movl    %eax, %cr3
> +	wbinvd
> +
> +	# Go back to the return point
> +	jmp ret_point
> +
> +save_registers:
> +	sgdt  saved_gdt
> +	sidt  saved_idt
> +	sldt  saved_ldt
> +
> +	pushl %edx
> +	movl %cr4, %edx
> +	movl %edx, saved_cr4
> +
> +	movl %cr0, %edx
> +	movl %edx, saved_cr0
> +
> +	popl %edx
> +
> +	movl %ebx, saved_context_ebx
> +	movl %ebp, saved_context_ebp
> +	movl %esi, saved_context_esi
> +	movl %edi, saved_context_edi
> +
> +	pushfl
> +	popl saved_context_eflags
> +
> +	ret
> +
> +
> +restore_registers:
> +	movl saved_context_ebp, %ebp
> +	movl saved_context_ebx, %ebx
> +	movl saved_context_esi, %esi
> +	movl saved_context_edi, %edi
> +
> +	pushl saved_context_eflags
> +	popfl
> +
> +	ret
> +
> +
> +ENTRY(do_olpc_suspend_lowlevel)
> +	call	save_processor_state
> +	call	save_registers
> +
> +	# This is the stack context we want to remember
> +	movl %esp, saved_context_esp
> +
> +	pushl	$3
> +	call	olpc_xo1_do_sleep
> +
> +	jmp	wakeup_start
> +	.p2align 4,,7
> +ret_point:
> +	movl    saved_context_esp, %esp
> +
> +	writepost 0x32
> +
> +	call	restore_registers
> +	call	restore_processor_state
> +	ret
> +
> +.data
> +ALIGN
> +
> +saved_gdt:     .long   0,0
> +saved_idt:     .long   0,0
> +saved_ldt:     .long   0
> +saved_cr4:     .long   0
> +saved_cr0:     .long   0
> +
> diff --git a/arch/x86/kernel/olpc-xo1.c b/arch/x86/kernel/olpc-xo1.c
> index f5442c0..9a06081 100644
> --- a/arch/x86/kernel/olpc-xo1.c
> +++ b/arch/x86/kernel/olpc-xo1.c
> @@ -16,6 +16,7 @@
>  #include <linux/pci_ids.h>
>  #include <linux/platform_device.h>
>  #include <linux/pm.h>
> +#include <linux/suspend.h>
>  
>  #include <asm/io.h>
>  #include <asm/olpc.h>
> @@ -33,12 +34,83 @@
>  #define PM_SSC		0x54
>  
>  /* PM registers (ACPI block) */
> +#define PM1_STS		0x00
>  #define PM1_CNT		0x08
>  #define PM_GPE0_STS	0x18
>  
> +#define CS5536_PM_PWRBTN (1 << 8)
> +
> +extern void do_olpc_suspend_lowlevel(void);
> +
>  static unsigned long acpi_base;
>  static unsigned long pms_base;
>  
> +static struct {
> +	unsigned long address;
> +	unsigned short segment;
> +} ofw_bios_entry = { 0xF0000 + PAGE_OFFSET, __KERNEL_CS };
> +
> +static int xo1_power_state_enter(suspend_state_t pm_state)
> +{
> +	int r;
> +
> +	/* Only STR is supported */
> +	if (pm_state != PM_SUSPEND_MEM)
> +		return -EINVAL;
> +
> +	r = olpc_ec_cmd(EC_SET_SCI_INHIBIT, NULL, 0, NULL, 0);
> +	if (r)
> +		return r;
> +
> +	/* Save CPU state */
> +	do_olpc_suspend_lowlevel();
> +
> +	/* Resume path starts here */
> +
> +	/* Tell the EC to stop inhibiting SCIs */
> +	olpc_ec_cmd(EC_SET_SCI_INHIBIT_RELEASE, NULL, 0, NULL, 0);
> +
> +	/*
> +	 * Tell the wireless module to restart USB communication.
> +	 * Must be done twice.
> +	 */
> +	olpc_ec_cmd(EC_WAKE_UP_WLAN, NULL, 0, NULL, 0);
> +	olpc_ec_cmd(EC_WAKE_UP_WLAN, NULL, 0, NULL, 0);
> +
> +	return 0;
> +}
> +
> +asmlinkage int olpc_xo1_do_sleep(u8 sleep_state)
> +{
> +	void *pgd_addr = __va(read_cr3());
> +	printk(KERN_ERR "xo1_do_sleep!\n"); /* this needs to remain here so
> +					      * that gcc doesn't optimize
> +					      * away our __va! */
> +
> +	/* Enable wakeup through power button */
> +	outl((CS5536_PM_PWRBTN << 16) | 0xFFFF, acpi_base + PM1_STS);
> +
> +	__asm__ __volatile__("movl %0,%%eax" : : "r" (pgd_addr));
> +	__asm__("call *(%%edi); cld"
> +		: : "D" (&ofw_bios_entry));
> +	__asm__ __volatile__("movb $0x34, %al\n\t"
> +			     "outb %al, $0x70\n\t"
> +			     "movb $0x30, %al\n\t"
> +			     "outb %al, $0x71\n\t");
> +	return 0;
> +}
> +
> +static int xo1_power_state_valid(suspend_state_t pm_state)
> +{
> +	/* suspend-to-RAM only */
> +	return pm_state == PM_SUSPEND_MEM;
> +}
> +
> +static struct platform_suspend_ops xo1_suspend_ops = {
> +	.valid = xo1_power_state_valid,
> +	.enter = xo1_power_state_enter,
> +};
> +
>  static void xo1_power_off(void)
>  {
>  	printk(KERN_INFO "OLPC XO-1 power off sequence...\n");
> @@ -101,6 +173,13 @@ static int __devinit olpc_xo1_probe(struct platform_device *pdev)
>  	if (r)
>  		return r;
>  
> +	/*
> +	 * Take a reference on ourself to prevent module unloading. We can't
> +	 * safely unload after changing the suspend handlers.
> +	 */
> +	__module_get(THIS_MODULE);
> +
> +	suspend_set_ops(&xo1_suspend_ops);
>  	pm_power_off = xo1_power_off;
>  
>  	printk(KERN_INFO "OLPC XO-1 support registered\n");
> diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
> index 43bbc29..dbdab67 100644
> --- a/arch/x86/mm/init_32.c
> +++ b/arch/x86/mm/init_32.c
> @@ -549,7 +549,7 @@ static void __init pagetable_init(void)
>  	permanent_kmaps_init(pgd_base);
>  }
>  
> -#ifdef CONFIG_ACPI_SLEEP
> +#if defined(CONFIG_ACPI_SLEEP) || defined(CONFIG_OLPC_XO1)
>  /*
>   * ACPI suspend needs this for resume, because things like the intel-agp
>   * driver might have split up a kernel 4MB mapping.
> @@ -561,11 +561,11 @@ static inline void save_pg_dir(void)
>  {
>  	copy_page(swsusp_pg_dir, swapper_pg_dir);
>  }
> -#else /* !CONFIG_ACPI_SLEEP */
> +#else /* !CONFIG_ACPI_SLEEP && !CONFIG_OLPC_XO1 */
>  static inline void save_pg_dir(void)
>  {
>  }
> -#endif /* !CONFIG_ACPI_SLEEP */
> +#endif /* !CONFIG_ACPI_SLEEP && !CONFIG_OLPC_XO1 */
>  
>  void zap_low_mappings(bool early)
>  {
> -- 

---
~Randy
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