diff options
Diffstat (limited to 'arch/arm/mach-tegra/sleep-tegra20.S')
| -rw-r--r-- | arch/arm/mach-tegra/sleep-tegra20.S | 200 |
1 files changed, 200 insertions, 0 deletions
diff --git a/arch/arm/mach-tegra/sleep-tegra20.S b/arch/arm/mach-tegra/sleep-tegra20.S index ad2ca07d0578..9f6bfafdd512 100644 --- a/arch/arm/mach-tegra/sleep-tegra20.S +++ b/arch/arm/mach-tegra/sleep-tegra20.S @@ -21,6 +21,8 @@ #include <linux/linkage.h> #include <asm/assembler.h> +#include <asm/proc-fns.h> +#include <asm/cp15.h> #include "sleep.h" #include "flowctrl.h" @@ -55,6 +57,9 @@ ENDPROC(tegra20_hotplug_shutdown) ENTRY(tegra20_cpu_shutdown) cmp r0, #0 moveq pc, lr @ must not be called for CPU 0 + mov32 r1, TEGRA_PMC_VIRT + PMC_SCRATCH41 + mov r12, #CPU_RESETTABLE + str r12, [r1] cpu_to_halt_reg r1, r0 ldr r3, =TEGRA_FLOW_CTRL_VIRT @@ -75,3 +80,198 @@ ENTRY(tegra20_cpu_shutdown) mov pc, lr ENDPROC(tegra20_cpu_shutdown) #endif + +#ifdef CONFIG_PM_SLEEP +/* + * tegra_pen_lock + * + * spinlock implementation with no atomic test-and-set and no coherence + * using Peterson's algorithm on strongly-ordered registers + * used to synchronize a cpu waking up from wfi with entering lp2 on idle + * + * The reference link of Peterson's algorithm: + * http://en.wikipedia.org/wiki/Peterson's_algorithm + * + * SCRATCH37 = r1 = !turn (inverted from Peterson's algorithm) + * on cpu 0: + * r2 = flag[0] (in SCRATCH38) + * r3 = flag[1] (in SCRATCH39) + * on cpu1: + * r2 = flag[1] (in SCRATCH39) + * r3 = flag[0] (in SCRATCH38) + * + * must be called with MMU on + * corrupts r0-r3, r12 + */ +ENTRY(tegra_pen_lock) + mov32 r3, TEGRA_PMC_VIRT + cpu_id r0 + add r1, r3, #PMC_SCRATCH37 + cmp r0, #0 + addeq r2, r3, #PMC_SCRATCH38 + addeq r3, r3, #PMC_SCRATCH39 + addne r2, r3, #PMC_SCRATCH39 + addne r3, r3, #PMC_SCRATCH38 + + mov r12, #1 + str r12, [r2] @ flag[cpu] = 1 + dsb + str r12, [r1] @ !turn = cpu +1: dsb + ldr r12, [r3] + cmp r12, #1 @ flag[!cpu] == 1? + ldreq r12, [r1] + cmpeq r12, r0 @ !turn == cpu? + beq 1b @ while !turn == cpu && flag[!cpu] == 1 + + mov pc, lr @ locked +ENDPROC(tegra_pen_lock) + +ENTRY(tegra_pen_unlock) + dsb + mov32 r3, TEGRA_PMC_VIRT + cpu_id r0 + cmp r0, #0 + addeq r2, r3, #PMC_SCRATCH38 + addne r2, r3, #PMC_SCRATCH39 + mov r12, #0 + str r12, [r2] + mov pc, lr +ENDPROC(tegra_pen_unlock) + +/* + * tegra20_cpu_clear_resettable(void) + * + * Called to clear the "resettable soon" flag in PMC_SCRATCH41 when + * it is expected that the secondary CPU will be idle soon. + */ +ENTRY(tegra20_cpu_clear_resettable) + mov32 r1, TEGRA_PMC_VIRT + PMC_SCRATCH41 + mov r12, #CPU_NOT_RESETTABLE + str r12, [r1] + mov pc, lr +ENDPROC(tegra20_cpu_clear_resettable) + +/* + * tegra20_cpu_set_resettable_soon(void) + * + * Called to set the "resettable soon" flag in PMC_SCRATCH41 when + * it is expected that the secondary CPU will be idle soon. + */ +ENTRY(tegra20_cpu_set_resettable_soon) + mov32 r1, TEGRA_PMC_VIRT + PMC_SCRATCH41 + mov r12, #CPU_RESETTABLE_SOON + str r12, [r1] + mov pc, lr +ENDPROC(tegra20_cpu_set_resettable_soon) + +/* + * tegra20_cpu_is_resettable_soon(void) + * + * Returns true if the "resettable soon" flag in PMC_SCRATCH41 has been + * set because it is expected that the secondary CPU will be idle soon. + */ +ENTRY(tegra20_cpu_is_resettable_soon) + mov32 r1, TEGRA_PMC_VIRT + PMC_SCRATCH41 + ldr r12, [r1] + cmp r12, #CPU_RESETTABLE_SOON + moveq r0, #1 + movne r0, #0 + mov pc, lr +ENDPROC(tegra20_cpu_is_resettable_soon) + +/* + * tegra20_sleep_cpu_secondary_finish(unsigned long v2p) + * + * Enters WFI on secondary CPU by exiting coherency. + */ +ENTRY(tegra20_sleep_cpu_secondary_finish) + stmfd sp!, {r4-r11, lr} + + mrc p15, 0, r11, c1, c0, 1 @ save actlr before exiting coherency + + /* Flush and disable the L1 data cache */ + bl tegra_disable_clean_inv_dcache + + mov32 r0, TEGRA_PMC_VIRT + PMC_SCRATCH41 + mov r3, #CPU_RESETTABLE + str r3, [r0] + + bl cpu_do_idle + + /* + * cpu may be reset while in wfi, which will return through + * tegra_resume to cpu_resume + * or interrupt may wake wfi, which will return here + * cpu state is unchanged - MMU is on, cache is on, coherency + * is off, and the data cache is off + * + * r11 contains the original actlr + */ + + bl tegra_pen_lock + + mov32 r3, TEGRA_PMC_VIRT + add r0, r3, #PMC_SCRATCH41 + mov r3, #CPU_NOT_RESETTABLE + str r3, [r0] + + bl tegra_pen_unlock + + /* Re-enable the data cache */ + mrc p15, 0, r10, c1, c0, 0 + orr r10, r10, #CR_C + mcr p15, 0, r10, c1, c0, 0 + isb + + mcr p15, 0, r11, c1, c0, 1 @ reenable coherency + + /* Invalidate the TLBs & BTAC */ + mov r1, #0 + mcr p15, 0, r1, c8, c3, 0 @ invalidate shared TLBs + mcr p15, 0, r1, c7, c1, 6 @ invalidate shared BTAC + dsb + isb + + /* the cpu was running with coherency disabled, + * caches may be out of date */ + bl v7_flush_kern_cache_louis + + ldmfd sp!, {r4 - r11, pc} +ENDPROC(tegra20_sleep_cpu_secondary_finish) + +/* + * tegra20_tear_down_cpu + * + * Switches the CPU cluster to PLL-P and enters sleep. + */ +ENTRY(tegra20_tear_down_cpu) + bl tegra_switch_cpu_to_pllp + b tegra20_enter_sleep +ENDPROC(tegra20_tear_down_cpu) + +/* + * tegra20_enter_sleep + * + * uses flow controller to enter sleep state + * executes from IRAM with SDRAM in selfrefresh when target state is LP0 or LP1 + * executes from SDRAM with target state is LP2 + */ +tegra20_enter_sleep: + mov32 r6, TEGRA_FLOW_CTRL_BASE + + mov r0, #FLOW_CTRL_WAIT_FOR_INTERRUPT + orr r0, r0, #FLOW_CTRL_HALT_CPU_IRQ | FLOW_CTRL_HALT_CPU_FIQ + cpu_id r1 + cpu_to_halt_reg r1, r1 + str r0, [r6, r1] + dsb + ldr r0, [r6, r1] /* memory barrier */ + +halted: + dsb + wfe /* CPU should be power gated here */ + isb + b halted + +#endif |