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Diffstat (limited to 'arch/arm/mach-omap2/sleep24xx.S')
| -rw-r--r-- | arch/arm/mach-omap2/sleep24xx.S | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/arch/arm/mach-omap2/sleep24xx.S b/arch/arm/mach-omap2/sleep24xx.S new file mode 100644 index 000000000..84d8c43ad --- /dev/null +++ b/arch/arm/mach-omap2/sleep24xx.S @@ -0,0 +1,91 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * linux/arch/arm/mach-omap2/sleep.S + * + * (C) Copyright 2004 + * Texas Instruments, <www.ti.com> + * Richard Woodruff <r-woodruff2@ti.com> + * + * (C) Copyright 2006 Nokia Corporation + * Fixed idle loop sleep + * Igor Stoppa <igor.stoppa@nokia.com> + */ + +#include <linux/linkage.h> +#include <asm/assembler.h> + +#include "omap24xx.h" +#include "sdrc.h" + +/* First address of reserved address space? apparently valid for OMAP2 & 3 */ +#define A_SDRC0_V (0xC0000000) + + .text + +/* + * omap24xx_cpu_suspend() - Forces OMAP into deep sleep state by completing + * SDRC shutdown then ARM shutdown. Upon wake MPU is back on so just restore + * SDRC. + * + * Input: + * R0 : DLL ctrl value pre-Sleep + * R1 : SDRC_DLLA_CTRL + * R2 : SDRC_POWER + * + * The if the DPLL is going to AutoIdle. It seems like the DPLL may be back on + * when we get called, but the DLL probably isn't. We will wait a bit more in + * case the DPLL isn't quite there yet. The code will wait on DLL for DDR even + * if in unlocked mode. + * + * For less than 242x-ES2.2 upon wake from a sleep mode where the external + * oscillator was stopped, a timing bug exists where a non-stabilized 12MHz + * clock can pass into the PRCM can cause problems at DSP and IVA. + * To work around this the code will switch to the 32kHz source prior to sleep. + * Post sleep we will shift back to using the DPLL. Apparently, + * CM_IDLEST_CLKGEN does not reflect the full clock change so you need to wait + * 3x12MHz + 3x32kHz clocks for a full switch. + * + * The DLL load value is not kept in RETENTION or OFF. It needs to be restored + * at wake + */ + .align 3 +ENTRY(omap24xx_cpu_suspend) + stmfd sp!, {r0 - r12, lr} @ save registers on stack + mov r3, #0x0 @ clear for mcr call + mcr p15, 0, r3, c7, c10, 4 @ memory barrier, hope SDR/DDR finished + nop + nop + ldr r4, [r2] @ read SDRC_POWER + orr r4, r4, #0x40 @ enable self refresh on idle req + mov r5, #0x2000 @ set delay (DPLL relock + DLL relock) + str r4, [r2] @ make it so + nop + mcr p15, 0, r3, c7, c0, 4 @ wait for interrupt + nop +loop: + subs r5, r5, #0x1 @ awake, wait just a bit + bne loop + + /* The DPLL has to be on before we take the DDR out of self refresh */ + bic r4, r4, #0x40 @ now clear self refresh bit. + str r4, [r2] @ write to SDRC_POWER + ldr r4, A_SDRC0 @ make a clock happen + ldr r4, [r4] @ read A_SDRC0 + nop @ start auto refresh only after clk ok + movs r0, r0 @ see if DDR or SDR + strne r0, [r1] @ rewrite DLLA to force DLL reload + addne r1, r1, #0x8 @ move to DLLB + strne r0, [r1] @ rewrite DLLB to force DLL reload + + mov r5, #0x1000 +loop2: + subs r5, r5, #0x1 + bne loop2 + /* resume*/ + ldmfd sp!, {r0 - r12, pc} @ restore regs and return + +A_SDRC0: + .word A_SDRC0_V + +ENTRY(omap24xx_cpu_suspend_sz) + .word . - omap24xx_cpu_suspend |