[ARM] S3C64XX: Initial support for PM (suspend to RAM)
Ben Dooks [Tue, 10 Mar 2009 18:19:35 +0000 (18:19 +0000)]
Add the initial support for the S3C64XX based systems to use
suspend-to-RAM to sleep.

Includes basic debugging for use with the SMDK6410 usign the
LEDs on the baseboard.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>

arch/arm/mach-s3c6400/include/mach/regs-clock.h [new file with mode: 0644]
arch/arm/plat-s3c/Kconfig
arch/arm/plat-s3c/include/plat/pm.h
arch/arm/plat-s3c/pm.c
arch/arm/plat-s3c64xx/Makefile
arch/arm/plat-s3c64xx/include/plat/irqs.h
arch/arm/plat-s3c64xx/include/plat/pm-core.h [new file with mode: 0644]
arch/arm/plat-s3c64xx/include/plat/regs-clock.h
arch/arm/plat-s3c64xx/irq-eint.c
arch/arm/plat-s3c64xx/pm.c [new file with mode: 0644]
arch/arm/plat-s3c64xx/sleep.S [new file with mode: 0644]

diff --git a/arch/arm/mach-s3c6400/include/mach/regs-clock.h b/arch/arm/mach-s3c6400/include/mach/regs-clock.h
new file mode 100644 (file)
index 0000000..a6c7f4e
--- /dev/null
@@ -0,0 +1,16 @@
+/* linux/arch/arm/mach-s3c6400/include/mach/regs-clock.h
+ *
+ * Copyright 2008 Openmoko, Inc.
+ * Copyright 2008 Simtec Electronics
+ *     http://armlinux.simtec.co.uk/
+ *     Ben Dooks <ben@simtec.co.uk>
+ *
+ * S3C64XX - clock register compatibility with s3c24xx
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+*/
+
+#include <plat/regs-clock.h>
+
index 042d34a..a4c5027 100644 (file)
@@ -71,6 +71,15 @@ config S3C2410_PM_DEBUG
          Resume code. See <file:Documentation/arm/Samsung-S3C24XX/Suspend.txt>
          for more information.
 
+config S3C_PM_DEBUG_LED_SMDK
+       bool "SMDK LED suspend/resume debugging"
+       depends on PM && (MACH_SMDK6410)
+       help
+         Say Y here to enable the use of the SMDK LEDs on the baseboard
+        for debugging of the state of the suspend and resume process.
+
+        Note, this currently only works for S3C64XX based SMDK boards.
+
 config S3C2410_PM_CHECK
        bool "S3C2410 PM Suspend Memory CRC"
        depends on PM && CRC32
index 5f8707e..7a79719 100644 (file)
@@ -127,6 +127,18 @@ extern void s3c_pm_dbg(const char *msg, ...);
 #define S3C_PMDBG(fmt...) printk(KERN_DEBUG fmt)
 #endif
 
+#ifdef CONFIG_S3C_PM_DEBUG_LED_SMDK
+/**
+ * s3c_pm_debug_smdkled() - Debug PM suspend/resume via SMDK Board LEDs
+ * @set: set bits for the state of the LEDs
+ * @clear: clear bits for the state of the LEDs.
+ */
+extern void s3c_pm_debug_smdkled(u32 set, u32 clear);
+
+#else
+static inline void s3c_pm_debug_smdkled(u32 set, u32 clear) { }
+#endif /* CONFIG_S3C_PM_DEBUG_LED_SMDK */
+
 /* suspend memory checking */
 
 #ifdef CONFIG_S3C2410_PM_CHECK
index 9957b53..8d97db2 100644 (file)
 
 #include <asm/cacheflush.h>
 #include <mach/hardware.h>
+#include <mach/map.h>
 
 #include <plat/regs-serial.h>
 #include <mach/regs-clock.h>
-#include <mach/regs-gpio.h>
-#include <mach/regs-mem.h>
 #include <mach/regs-irq.h>
 #include <asm/irq.h>
 
@@ -326,6 +325,9 @@ static int s3c_pm_enter(suspend_state_t state)
 
        S3C_PMDBG("%s: post sleep, preparing to return\n", __func__);
 
+       /* LEDs should now be 1110 */
+       s3c_pm_debug_smdkled(1 << 1, 0);
+
        s3c_pm_check_restore();
 
        /* ok, let's return from sleep */
index 2e6d79b..b2bc2a9 100644 (file)
@@ -24,6 +24,11 @@ obj-y                                += gpiolib.o
 obj-$(CONFIG_CPU_S3C6400_INIT) += s3c6400-init.o
 obj-$(CONFIG_CPU_S3C6400_CLOCK)        += s3c6400-clock.o
 
+# PM support
+
+obj-$(CONFIG_PM)               += pm.o
+obj-$(CONFIG_PM)               += sleep.o
+
 # Device setup
 
 obj-$(CONFIG_S3C64XX_SETUP_I2C0) += setup-i2c0.o
index f865bf4..743a700 100644 (file)
 
 #define S3C_EINT(x)            ((x) + S3C_IRQ_EINT_BASE)
 #define IRQ_EINT(x)            S3C_EINT(x)
+#define IRQ_EINT_BIT(x)                ((x) - S3C_EINT(0))
 
 /* Next the external interrupt groups. These are similar to the IRQ_EINT(x)
  * that they are sourced from the GPIO pins but with a different scheme for
diff --git a/arch/arm/plat-s3c64xx/include/plat/pm-core.h b/arch/arm/plat-s3c64xx/include/plat/pm-core.h
new file mode 100644 (file)
index 0000000..d347de3
--- /dev/null
@@ -0,0 +1,98 @@
+/* linux/arch/arm/plat-s3c64xx/include/plat/pm-core.h
+ *
+ * Copyright 2008 Openmoko, Inc.
+ * Copyright 2008 Simtec Electronics
+ *      Ben Dooks <ben@simtec.co.uk>
+ *      http://armlinux.simtec.co.uk/
+ *
+ * S3C64XX - PM core support for arch/arm/plat-s3c/pm.c
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <plat/regs-gpio.h>
+
+static inline void s3c_pm_debug_init_uart(void)
+{
+       u32 tmp = __raw_readl(S3C_PCLK_GATE);
+
+       /* As a note, since the S3C64XX UARTs generally have multiple
+        * clock sources, we simply enable PCLK at the moment and hope
+        * that the resume settings for the UART are suitable for the
+        * use with PCLK.
+        */
+
+       tmp |= S3C_CLKCON_PCLK_UART0;
+       tmp |= S3C_CLKCON_PCLK_UART1;
+       tmp |= S3C_CLKCON_PCLK_UART2;
+       tmp |= S3C_CLKCON_PCLK_UART3;
+
+       __raw_writel(tmp, S3C_PCLK_GATE);
+       udelay(10);
+}
+
+static inline void s3c_pm_arch_prepare_irqs(void)
+{
+       /* VIC should have already been taken care of */
+
+       /* clear any pending EINT0 interrupts */
+       __raw_writel(__raw_readl(S3C64XX_EINT0PEND), S3C64XX_EINT0PEND);
+}
+
+static inline void s3c_pm_arch_stop_clocks(void)
+{
+}
+
+static inline void s3c_pm_arch_show_resume_irqs(void)
+{
+}
+
+/* make these defines, we currently do not have any need to change
+ * the IRQ wake controls depending on the CPU we are running on */
+
+#define s3c_irqwake_eintallow  ((1 << 28) - 1)
+#define s3c_irqwake_intallow   (0)
+
+static inline void s3c_pm_arch_update_uart(void __iomem *regs,
+                                          struct pm_uart_save *save)
+{
+       u32 ucon = __raw_readl(regs + S3C2410_UCON);
+       u32 ucon_clk = ucon & S3C6400_UCON_CLKMASK;
+       u32 save_clk = save->ucon & S3C6400_UCON_CLKMASK;
+       u32 new_ucon;
+       u32 delta;
+
+       /* S3C64XX UART blocks only support level interrupts, so ensure that
+        * when we restore unused UART blocks we force the level interrupt
+        * settigs. */
+       save->ucon |= S3C2410_UCON_TXILEVEL | S3C2410_UCON_RXILEVEL;
+
+       /* We have a constraint on changing the clock type of the UART
+        * between UCLKx and PCLK, so ensure that when we restore UCON
+        * that the CLK field is correctly modified if the bootloader
+        * has changed anything.
+        */
+       if (ucon_clk != save_clk) {
+               new_ucon = save->ucon;
+               delta = ucon_clk ^ save_clk;
+
+               /* change from UCLKx => wrong PCLK,
+                * either UCLK can be tested for by a bit-test
+                * with UCLK0 */
+               if (ucon_clk & S3C6400_UCON_UCLK0 &&
+                   !(save_clk & S3C6400_UCON_UCLK0) &&
+                   delta & S3C6400_UCON_PCLK2) {
+                       new_ucon &= ~S3C6400_UCON_UCLK0;
+               } else if (delta == S3C6400_UCON_PCLK2) {
+                       /* as an precaution, don't change from
+                        * PCLK2 => PCLK or vice-versa */
+                       new_ucon ^= S3C6400_UCON_PCLK2;
+               }
+
+               S3C_PMDBG("ucon change %04x => %04x (save=%04x)\n",
+                         ucon, new_ucon, save->ucon);
+               save->ucon = new_ucon;
+       }
+}
index b1082c1..52836d4 100644 (file)
@@ -32,6 +32,7 @@
 #define S3C_HCLK_GATE          S3C_CLKREG(0x30)
 #define S3C_PCLK_GATE          S3C_CLKREG(0x34)
 #define S3C_SCLK_GATE          S3C_CLKREG(0x38)
+#define S3C_MEM0_GATE          S3C_CLKREG(0x3C)
 
 /* CLKDIV0 */
 #define S3C6400_CLKDIV0_MFC_MASK       (0xf << 28)
index 47e5155..f81b7b8 100644 (file)
@@ -14,6 +14,7 @@
 
 #include <linux/kernel.h>
 #include <linux/interrupt.h>
+#include <linux/sysdev.h>
 #include <linux/gpio.h>
 #include <linux/irq.h>
 #include <linux/io.h>
@@ -26,6 +27,7 @@
 
 #include <mach/map.h>
 #include <plat/cpu.h>
+#include <plat/pm.h>
 
 #define eint_offset(irq)       ((irq) - IRQ_EINT(0))
 #define eint_irq_to_bit(irq)   (1 << eint_offset(irq))
@@ -134,6 +136,7 @@ static struct irq_chip s3c_irq_eint = {
        .mask_ack       = s3c_irq_eint_maskack,
        .ack            = s3c_irq_eint_ack,
        .set_type       = s3c_irq_eint_set_type,
+       .set_wake       = s3c_irqext_wake,
 };
 
 /* s3c_irq_demux_eint
diff --git a/arch/arm/plat-s3c64xx/pm.c b/arch/arm/plat-s3c64xx/pm.c
new file mode 100644 (file)
index 0000000..98190aa
--- /dev/null
@@ -0,0 +1,186 @@
+/* linux/arch/arm/plat-s3c64xx/pm.c
+ *
+ * Copyright 2008 Openmoko, Inc.
+ * Copyright 2008 Simtec Electronics
+ *     Ben Dooks <ben@simtec.co.uk>
+ *     http://armlinux.simtec.co.uk/
+ *
+ * S3C64XX CPU PM support.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+*/
+
+#include <linux/init.h>
+#include <linux/suspend.h>
+#include <linux/serial_core.h>
+#include <linux/io.h>
+
+#include <mach/map.h>
+
+#include <plat/pm.h>
+#include <plat/regs-sys.h>
+#include <plat/regs-gpio.h>
+#include <plat/regs-clock.h>
+#include <plat/regs-syscon-power.h>
+#include <plat/regs-gpio-memport.h>
+
+#ifdef CONFIG_S3C_PM_DEBUG_LED_SMDK
+#include <plat/gpio-bank-n.h>
+
+void s3c_pm_debug_smdkled(u32 set, u32 clear)
+{
+       unsigned long flags;
+       u32 reg;
+
+       local_irq_save(flags);
+       reg = __raw_readl(S3C64XX_GPNCON);
+       reg &= ~(S3C64XX_GPN_CONMASK(12) | S3C64XX_GPN_CONMASK(13) |
+                S3C64XX_GPN_CONMASK(14) | S3C64XX_GPN_CONMASK(15));
+       reg |= S3C64XX_GPN_OUTPUT(12) | S3C64XX_GPN_OUTPUT(13) |
+              S3C64XX_GPN_OUTPUT(14) | S3C64XX_GPN_OUTPUT(15);
+       __raw_writel(reg, S3C64XX_GPNCON);
+
+       reg = __raw_readl(S3C64XX_GPNDAT);
+       reg &= ~(clear << 12);
+       reg |= set << 12;
+       __raw_writel(reg, S3C64XX_GPNDAT);
+
+       local_irq_restore(flags);
+}
+#endif
+
+static struct sleep_save core_save[] = {
+       SAVE_ITEM(S3C_APLL_LOCK),
+       SAVE_ITEM(S3C_MPLL_LOCK),
+       SAVE_ITEM(S3C_EPLL_LOCK),
+       SAVE_ITEM(S3C_CLK_SRC),
+       SAVE_ITEM(S3C_CLK_DIV0),
+       SAVE_ITEM(S3C_CLK_DIV1),
+       SAVE_ITEM(S3C_CLK_DIV2),
+       SAVE_ITEM(S3C_CLK_OUT),
+       SAVE_ITEM(S3C_HCLK_GATE),
+       SAVE_ITEM(S3C_PCLK_GATE),
+       SAVE_ITEM(S3C_SCLK_GATE),
+       SAVE_ITEM(S3C_MEM0_GATE),
+
+       SAVE_ITEM(S3C_EPLL_CON1),
+       SAVE_ITEM(S3C_EPLL_CON0),
+
+       SAVE_ITEM(S3C64XX_MEM0DRVCON),
+       SAVE_ITEM(S3C64XX_MEM1DRVCON),
+
+#ifndef CONFIG_CPU_FREQ
+       SAVE_ITEM(S3C_APLL_CON),
+       SAVE_ITEM(S3C_MPLL_CON),
+#endif
+};
+
+static struct sleep_save misc_save[] = {
+       SAVE_ITEM(S3C64XX_AHB_CON0),
+       SAVE_ITEM(S3C64XX_AHB_CON1),
+       SAVE_ITEM(S3C64XX_AHB_CON2),
+       
+       SAVE_ITEM(S3C64XX_SPCON),
+
+       SAVE_ITEM(S3C64XX_MEM0CONSTOP),
+       SAVE_ITEM(S3C64XX_MEM1CONSTOP),
+       SAVE_ITEM(S3C64XX_MEM0CONSLP0),
+       SAVE_ITEM(S3C64XX_MEM0CONSLP1),
+       SAVE_ITEM(S3C64XX_MEM1CONSLP),
+};
+
+void s3c_pm_configure_extint(void)
+{
+       __raw_writel(s3c_irqwake_eintmask, S3C64XX_EINT_MASK);
+}
+
+void s3c_pm_save_gpios(void)
+{
+       /* currently, unless the bootloader does something really stupid
+        * the gpio blocks should be maintained over their sleep.
+        */
+}
+
+void s3c_pm_restore_gpios(void)
+{
+}
+
+void s3c_pm_restore_core(void)
+{
+       __raw_writel(0, S3C64XX_EINT_MASK);
+
+       s3c_pm_debug_smdkled(1 << 2, 0);
+
+       s3c_pm_do_restore_core(core_save, ARRAY_SIZE(core_save));
+       s3c_pm_do_restore(misc_save, ARRAY_SIZE(misc_save));
+}
+
+void s3c_pm_save_core(void)
+{
+       s3c_pm_do_save(misc_save, ARRAY_SIZE(misc_save));
+       s3c_pm_do_save(core_save, ARRAY_SIZE(core_save));
+}
+
+/* since both s3c6400 and s3c6410 share the same sleep pm calls, we
+ * put the per-cpu code in here until any new cpu comes along and changes
+ * this.
+ */
+
+#include <plat/regs-gpio.h>
+
+static void s3c64xx_cpu_suspend(void)
+{
+       unsigned long tmp;
+
+       /* set our standby method to sleep */
+
+       tmp = __raw_readl(S3C64XX_PWR_CFG);
+       tmp &= ~S3C64XX_PWRCFG_CFG_WFI_MASK;
+       tmp |= S3C64XX_PWRCFG_CFG_WFI_SLEEP;
+       __raw_writel(tmp, S3C64XX_PWR_CFG);
+
+       /* clear any old wakeup */
+
+       __raw_writel(__raw_readl(S3C64XX_WAKEUP_STAT),
+                    S3C64XX_WAKEUP_STAT);
+
+       /* set the LED state to 0110 over sleep */
+       s3c_pm_debug_smdkled(3 << 1, 0xf);
+
+       /* issue the standby signal into the pm unit. Note, we
+        * issue a write-buffer drain just in case */
+
+       tmp = 0;
+
+       asm("b 1f\n\t"
+           ".align 5\n\t"
+           "1:\n\t"
+           "mcr p15, 0, %0, c7, c10, 5\n\t"
+           "mcr p15, 0, %0, c7, c10, 4\n\t"
+           "mcr p15, 0, %0, c7, c0, 4" :: "r" (tmp));
+
+       /* we should never get past here */
+
+       panic("sleep resumed to originator?");
+}
+
+static void s3c64xx_pm_prepare(void)
+{
+       /* store address of resume. */
+       __raw_writel(virt_to_phys(s3c_cpu_resume), S3C64XX_INFORM0);
+
+       /* ensure previous wakeup state is cleared before sleeping */
+       __raw_writel(__raw_readl(S3C64XX_WAKEUP_STAT), S3C64XX_WAKEUP_STAT);
+}
+
+static int s3c64xx_pm_init(void)
+{
+       pm_cpu_prep = s3c64xx_pm_prepare;
+       pm_cpu_sleep = s3c64xx_cpu_suspend;
+       pm_uart_udivslot = 1;
+       return 0;
+}
+
+arch_initcall(s3c64xx_pm_init);
diff --git a/arch/arm/plat-s3c64xx/sleep.S b/arch/arm/plat-s3c64xx/sleep.S
new file mode 100644 (file)
index 0000000..8e71fe9
--- /dev/null
@@ -0,0 +1,144 @@
+/* linux/0arch/arm/plat-s3c64xx/sleep.S
+ *
+ * Copyright 2008 Openmoko, Inc.
+ * Copyright 2008 Simtec Electronics
+ *     Ben Dooks <ben@simtec.co.uk>
+ *     http://armlinux.simtec.co.uk/
+ *
+ * S3C64XX CPU sleep code
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+*/
+
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+#include <mach/map.h>
+
+#undef S3C64XX_VA_GPIO
+#define S3C64XX_VA_GPIO (0x0)
+
+#include <plat/regs-gpio.h>
+#include <plat/gpio-bank-n.h>
+
+#define LL_UART (S3C_PA_UART + (0x400 * CONFIG_S3C_LOWLEVEL_UART_PORT))
+
+       .text
+
+       /* s3c_cpu_save
+        *
+        * Save enough processor state to allow the restart of the pm.c
+        * code after resume.
+        *
+        * entry:
+        *      r0 = pointer to the save block
+       */
+
+ENTRY(s3c_cpu_save)
+       stmfd   sp!, { r4 - r12, lr }
+
+       mrc     p15, 0, r4, c13, c0, 0  @ FCSE/PID
+       mrc     p15, 0, r5, c3, c0, 0   @ Domain ID
+       mrc     p15, 0, r6, c2, c0, 0   @ Translation Table BASE0
+       mrc     p15, 0, r7, c2, c0, 1   @ Translation Table BASE1
+       mrc     p15, 0, r8, c2, c0, 2   @ Translation Table Control
+       mrc     p15, 0, r9, c1, c0, 0   @ Control register
+       mrc     p15, 0, r10, c1, c0, 1  @ Auxiliary control register
+       mrc     p15, 0, r11, c1, c0, 2  @ Co-processor access controls
+
+       stmia   r0, { r4 - r13 }        @ Save CP registers and SP
+
+       @@ save our state to ram
+       bl      s3c_pm_cb_flushcache
+
+       @@ call final suspend code
+       ldr     r0, =pm_cpu_sleep
+       ldr     pc, [r0]
+       
+       @@ return to the caller, after the MMU is turned on.
+       @@ restore the last bits of the stack and return.
+resume_with_mmu:
+       ldmfd   sp!, { r4 - r12, pc }   @ return, from sp from s3c_cpu_save
+
+       .data
+
+       /* the next bit is code, but it requires easy access to the
+        * s3c_sleep_save_phys data before the MMU is switched on, so
+        * we store the code that needs this variable in the .data where
+        * the value can be written to (the .text segment is RO).
+       */
+
+       .global s3c_sleep_save_phys
+s3c_sleep_save_phys:
+       .word   0
+
+       /* Sleep magic, the word before the resume entry point so that the
+        * bootloader can check for a resumeable image. */
+
+       .word   0x2bedf00d
+
+       /* s3c_cpu_reusme
+        *
+        * This is the entry point, stored by whatever method the bootloader
+        * requires to get the kernel runnign again. This code expects to be
+        * entered with no caches live and the MMU disabled. It will then
+        * restore the MMU and other basic CP registers saved and restart
+        * the kernel C code to finish the resume code.
+       */
+
+ENTRY(s3c_cpu_resume)
+       msr     cpsr_c, #PSR_I_BIT | PSR_F_BIT | SVC_MODE
+       ldr     r2, =LL_UART            /* for debug */
+
+#ifdef CONFIG_S3C_PM_DEBUG_LED_SMDK
+       /* Initialise the GPIO state if we are debugging via the SMDK LEDs,
+        * as the uboot version supplied resets these to inputs during the
+        * resume checks.
+       */
+
+       ldr     r3, =S3C64XX_PA_GPIO
+       ldr     r0, [ r3, #S3C64XX_GPNCON ]
+       bic     r0, r0, #(S3C64XX_GPN_CONMASK(12) | S3C64XX_GPN_CONMASK(13) | \
+                         S3C64XX_GPN_CONMASK(14) | S3C64XX_GPN_CONMASK(15))
+       orr     r0, r0, #(S3C64XX_GPN_OUTPUT(12) | S3C64XX_GPN_OUTPUT(13) | \
+                         S3C64XX_GPN_OUTPUT(14) | S3C64XX_GPN_OUTPUT(15))
+       str     r0, [ r3, #S3C64XX_GPNCON ]
+
+       ldr     r0, [ r3, #S3C64XX_GPNDAT ]
+       bic     r0, r0, #0xf << 12                      @ GPN12..15
+       orr     r0, r0, #1 << 15                        @ GPN15
+       str     r0, [ r3, #S3C64XX_GPNDAT ]
+#endif
+
+       /* __v6_setup from arch/arm/mm/proc-v6.S, ensure that the caches
+        * are thoroughly cleaned just in case the bootloader didn't do it
+        * for us. */
+       mov     r0, #0
+       mcr     p15, 0, r0, c7, c14, 0          @ clean+invalidate D cache
+       mcr     p15, 0, r0, c7, c5, 0           @ invalidate I cache
+       mcr     p15, 0, r0, c7, c15, 0          @ clean+invalidate cache
+       mcr     p15, 0, r0, c7, c10, 4          @ drain write buffer
+       @@mcr   p15, 0, r0, c8, c7, 0           @ invalidate I + D TLBs
+       @@mcr   p15, 0, r0, c7, c7, 0           @ Invalidate I + D caches
+
+       ldr     r0, s3c_sleep_save_phys
+       ldmia   r0, { r4 - r13 }
+
+       mcr     p15, 0, r4, c13, c0, 0  @ FCSE/PID
+       mcr     p15, 0, r5, c3, c0, 0   @ Domain ID
+       mcr     p15, 0, r6, c2, c0, 0   @ Translation Table BASE0
+       mcr     p15, 0, r7, c2, c0, 1   @ Translation Table BASE1
+       mcr     p15, 0, r8, c2, c0, 2   @ Translation Table Control
+       mcr     p15, 0, r10, c1, c0, 1  @ Auxiliary control register
+
+       mov     r0, #0                  @ restore copro access controls
+       mcr     p15, 0, r11, c1, c0, 2  @ Co-processor access controls
+       mcr     p15, 0, r0, c7, c5, 4
+
+       ldr     r2, =resume_with_mmu
+       mcr     p15, 0, r9, c1, c0, 0           /* turn mmu back on */
+       nop
+       mov     pc, r2                          /* jump back */
+
+       .end