aboutsummaryrefslogtreecommitdiffstats
path: root/arch/arm/mach-pxa/sleep.S
diff options
context:
space:
mode:
Diffstat (limited to 'arch/arm/mach-pxa/sleep.S')
-rw-r--r--arch/arm/mach-pxa/sleep.S194
1 files changed, 194 insertions, 0 deletions
diff --git a/arch/arm/mach-pxa/sleep.S b/arch/arm/mach-pxa/sleep.S
new file mode 100644
index 0000000..16cad2c
--- /dev/null
+++ b/arch/arm/mach-pxa/sleep.S
@@ -0,0 +1,194 @@
+/*
+ * Low-level PXA250/210 sleep/wakeUp support
+ *
+ * Initial SA1110 code:
+ * Copyright (c) 2001 Cliff Brake <cbrake@accelent.com>
+ *
+ * Adapted for PXA by Nicolas Pitre:
+ * Copyright (c) 2002 Monta Vista Software, Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License.
+ */
+
+#include <linux/config.h>
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+#include <asm/hardware.h>
+
+#include <asm/arch/pxa-regs.h>
+
+ .text
+
+/*
+ * pxa_cpu_suspend()
+ *
+ * Forces CPU into sleep state
+ */
+
+ENTRY(pxa_cpu_suspend)
+
+ mra r2, r3, acc0
+ stmfd sp!, {r2 - r12, lr} @ save registers on stack
+
+ @ get coprocessor registers
+ mrc p14, 0, r3, c6, c0, 0 @ clock configuration, for turbo mode
+ mrc p15, 0, r4, c15, c1, 0 @ CP access reg
+ mrc p15, 0, r5, c13, c0, 0 @ PID
+ mrc p15, 0, r6, c3, c0, 0 @ domain ID
+ mrc p15, 0, r7, c2, c0, 0 @ translation table base addr
+ mrc p15, 0, r8, c1, c1, 0 @ auxiliary control reg
+ mrc p15, 0, r9, c1, c0, 0 @ control reg
+
+ bic r3, r3, #2 @ clear frequency change bit
+
+ @ store them plus current virtual stack ptr on stack
+ mov r10, sp
+ stmfd sp!, {r3 - r10}
+
+ @ preserve phys address of stack
+ mov r0, sp
+ bl sleep_phys_sp
+ ldr r1, =sleep_save_sp
+ str r0, [r1]
+
+ @ clean data cache
+ bl xscale_flush_kern_cache_all
+
+ @ Put the processor to sleep
+ @ (also workaround for sighting 28071)
+
+ @ prepare value for sleep mode
+ mov r1, #3 @ sleep mode
+
+ @ prepare to put SDRAM into self-refresh manually
+ ldr r4, =MDREFR
+ ldr r5, [r4]
+ orr r5, r5, #MDREFR_SLFRSH
+
+ @ prepare pointer to physical address 0 (virtual mapping in generic.c)
+ mov r2, #UNCACHED_PHYS_0
+
+ @ Intel PXA255 Specification Update notes problems
+ @ about suspending with PXBus operating above 133MHz
+ @ (see Errata 31, GPIO output signals, ... unpredictable in sleep
+ @
+ @ We keep the change-down close to the actual suspend on SDRAM
+ @ as possible to eliminate messing about with the refresh clock
+ @ as the system will restore with the original speed settings
+ @
+ @ Ben Dooks, 13-Sep-2004
+
+ ldr r6, =CCCR
+ ldr r8, [r6] @ keep original value for resume
+
+ @ ensure x1 for run and turbo mode with memory clock
+ bic r7, r8, #CCCR_M_MASK | CCCR_N_MASK
+ orr r7, r7, #(1<<5) | (2<<7)
+
+ @ check that the memory frequency is within limits
+ and r14, r7, #CCCR_L_MASK
+ teq r14, #1
+ bicne r7, r7, #CCCR_L_MASK
+ orrne r7, r7, #1 @@ 99.53MHz
+
+ @ get ready for the change
+
+ @ note, turbo is not preserved over sleep so there is no
+ @ point in preserving it here. we save it on the stack with the
+ @ other CP registers instead.
+ mov r0, #0
+ mcr p14, 0, r0, c6, c0, 0
+ orr r0, r0, #2 @ initiate change bit
+
+ @ align execution to a cache line
+ b 1f
+
+ .ltorg
+ .align 5
+1:
+
+ @ All needed values are now in registers.
+ @ These last instructions should be in cache
+
+ @ initiate the frequency change...
+ str r7, [r6]
+ mcr p14, 0, r0, c6, c0, 0
+
+ @ restore the original cpu speed value for resume
+ str r8, [r6]
+
+ @ put SDRAM into self-refresh
+ str r5, [r4]
+
+ @ force address lines low by reading at physical address 0
+ ldr r3, [r2]
+
+ @ enter sleep mode
+ mcr p14, 0, r1, c7, c0, 0
+
+20: b 20b @ loop waiting for sleep
+
+/*
+ * cpu_pxa_resume()
+ *
+ * entry point from bootloader into kernel during resume
+ *
+ * Note: Yes, part of the following code is located into the .data section.
+ * This is to allow sleep_save_sp to be accessed with a relative load
+ * while we can't rely on any MMU translation. We could have put
+ * sleep_save_sp in the .text section as well, but some setups might
+ * insist on it to be truly read-only.
+ */
+
+ .data
+ .align 5
+ENTRY(pxa_cpu_resume)
+ mov r0, #PSR_I_BIT | PSR_F_BIT | MODE_SVC @ set SVC, irqs off
+ msr cpsr_c, r0
+
+ ldr r0, sleep_save_sp @ stack phys addr
+ ldr r2, =resume_after_mmu @ its absolute virtual address
+ ldmfd r0, {r3 - r9, sp} @ CP regs + virt stack ptr
+
+ mov r1, #0
+ mcr p15, 0, r1, c8, c7, 0 @ invalidate I & D TLBs
+ mcr p15, 0, r1, c7, c7, 0 @ invalidate I & D caches, BTB
+
+#ifdef CONFIG_XSCALE_CACHE_ERRATA
+ bic r9, r9, #0x0004 @ see cpu_xscale_proc_init
+#endif
+
+ mcr p14, 0, r3, c6, c0, 0 @ clock configuration, turbo mode.
+ mcr p15, 0, r4, c15, c1, 0 @ CP access reg
+ mcr p15, 0, r5, c13, c0, 0 @ PID
+ mcr p15, 0, r6, c3, c0, 0 @ domain ID
+ mcr p15, 0, r7, c2, c0, 0 @ translation table base addr
+ mcr p15, 0, r8, c1, c1, 0 @ auxiliary control reg
+ b resume_turn_on_mmu @ cache align execution
+
+ .align 5
+resume_turn_on_mmu:
+ mcr p15, 0, r9, c1, c0, 0 @ turn on MMU, caches, etc.
+
+ @ Let us ensure we jump to resume_after_mmu only when the mcr above
+ @ actually took effect. They call it the "cpwait" operation.
+ mrc p15, 0, r1, c2, c0, 0 @ queue a dependency on CP15
+ sub pc, r2, r1, lsr #32 @ jump to virtual addr
+ nop
+ nop
+ nop
+
+sleep_save_sp:
+ .word 0 @ preserve stack phys ptr here
+
+ .text
+resume_after_mmu:
+#ifdef CONFIG_XSCALE_CACHE_ERRATA
+ bl cpu_xscale_proc_init
+#endif
+ ldmfd sp!, {r2, r3}
+ mar acc0, r2, r3
+ ldmfd sp!, {r4 - r12, pc} @ return to caller
+
+