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

From: Daniel Drake
Date: Tue Oct 19 2010 - 18:02:10 EST

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

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)
{
--
1.7.2.3

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