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Diffstat (limited to 'arch/arm/mach-tegra/sleep-tegra20.S')
| -rw-r--r-- | arch/arm/mach-tegra/sleep-tegra20.S | 277 |
1 files changed, 277 insertions, 0 deletions
diff --git a/arch/arm/mach-tegra/sleep-tegra20.S b/arch/arm/mach-tegra/sleep-tegra20.S new file mode 100644 index 00000000..e3f2417c --- /dev/null +++ b/arch/arm/mach-tegra/sleep-tegra20.S @@ -0,0 +1,277 @@ +/* + * Copyright (c) 2010-2012, NVIDIA Corporation. All rights reserved. + * Copyright (c) 2011, Google, Inc. + * + * Author: Colin Cross <ccross@android.com> + * Gary King <gking@nvidia.com> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/linkage.h> + +#include <asm/assembler.h> +#include <asm/proc-fns.h> +#include <asm/cp15.h> + +#include "sleep.h" +#include "flowctrl.h" + +#if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_PM_SLEEP) +/* + * tegra20_hotplug_shutdown(void) + * + * puts the current cpu in reset + * should never return + */ +ENTRY(tegra20_hotplug_shutdown) + /* Put this CPU down */ + cpu_id r0 + bl tegra20_cpu_shutdown + mov pc, lr @ should never get here +ENDPROC(tegra20_hotplug_shutdown) + +/* + * tegra20_cpu_shutdown(int cpu) + * + * r0 is cpu to reset + * + * puts the specified CPU in wait-for-event mode on the flow controller + * and puts the CPU in reset + * can be called on the current cpu or another cpu + * if called on the current cpu, does not return + * MUST NOT BE CALLED FOR CPU 0. + * + * corrupts r0-r3, r12 + */ +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 + mov r2, #FLOW_CTRL_WAITEVENT | FLOW_CTRL_JTAG_RESUME + str r2, [r3, r1] @ put flow controller in wait event mode + ldr r2, [r3, r1] + isb + dsb + movw r1, 0x1011 + mov r1, r1, lsl r0 + ldr r3, =TEGRA_CLK_RESET_VIRT + str r1, [r3, #0x340] @ put slave CPU in reset + isb + dsb + cpu_id r3 + cmp r3, r0 + beq . + 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 tegra_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 |