diff options
Diffstat (limited to 'arch/arm/mach-at91/pm_slowclock.S')
| -rw-r--r-- | arch/arm/mach-at91/pm_slowclock.S | 283 |
1 files changed, 283 insertions, 0 deletions
diff --git a/arch/arm/mach-at91/pm_slowclock.S b/arch/arm/mach-at91/pm_slowclock.S new file mode 100644 index 00000000000..987fab3d846 --- /dev/null +++ b/arch/arm/mach-at91/pm_slowclock.S @@ -0,0 +1,283 @@ +/* + * arch/arm/mach-at91/pm_slow_clock.S + * + * Copyright (C) 2006 Savin Zlobec + * + * AT91SAM9 support: + * Copyright (C) 2007 Anti Sullin <anti.sullin@artecdesign.ee + * + * 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 <mach/hardware.h> +#include <mach/at91_pmc.h> + +#ifdef CONFIG_ARCH_AT91RM9200 +#include <mach/at91rm9200_mc.h> +#elif defined(CONFIG_ARCH_AT91CAP9) +#include <mach/at91cap9_ddrsdr.h> +#else +#include <mach/at91sam9_sdramc.h> +#endif + + +#ifdef CONFIG_ARCH_AT91SAM9263 +/* + * FIXME either or both the SDRAM controllers (EB0, EB1) might be in use; + * handle those cases both here and in the Suspend-To-RAM support. + */ +#define AT91_SDRAMC AT91_SDRAMC0 +#warning Assuming EB1 SDRAM controller is *NOT* used +#endif + +/* + * When SLOWDOWN_MASTER_CLOCK is defined we will also slow down the Master + * clock during suspend by adjusting its prescalar and divisor. + * NOTE: This hasn't been shown to be stable on SAM9s; and on the RM9200 there + * are errata regarding adjusting the prescalar and divisor. + */ +#undef SLOWDOWN_MASTER_CLOCK + +#define MCKRDY_TIMEOUT 1000 +#define MOSCRDY_TIMEOUT 1000 +#define PLLALOCK_TIMEOUT 1000 +#define PLLBLOCK_TIMEOUT 1000 + + +/* + * Wait until master clock is ready (after switching master clock source) + */ + .macro wait_mckrdy + mov r4, #MCKRDY_TIMEOUT +1: sub r4, r4, #1 + cmp r4, #0 + beq 2f + ldr r3, [r1, #(AT91_PMC_SR - AT91_PMC)] + tst r3, #AT91_PMC_MCKRDY + beq 1b +2: + .endm + +/* + * Wait until master oscillator has stabilized. + */ + .macro wait_moscrdy + mov r4, #MOSCRDY_TIMEOUT +1: sub r4, r4, #1 + cmp r4, #0 + beq 2f + ldr r3, [r1, #(AT91_PMC_SR - AT91_PMC)] + tst r3, #AT91_PMC_MOSCS + beq 1b +2: + .endm + +/* + * Wait until PLLA has locked. + */ + .macro wait_pllalock + mov r4, #PLLALOCK_TIMEOUT +1: sub r4, r4, #1 + cmp r4, #0 + beq 2f + ldr r3, [r1, #(AT91_PMC_SR - AT91_PMC)] + tst r3, #AT91_PMC_LOCKA + beq 1b +2: + .endm + +/* + * Wait until PLLB has locked. + */ + .macro wait_pllblock + mov r4, #PLLBLOCK_TIMEOUT +1: sub r4, r4, #1 + cmp r4, #0 + beq 2f + ldr r3, [r1, #(AT91_PMC_SR - AT91_PMC)] + tst r3, #AT91_PMC_LOCKB + beq 1b +2: + .endm + + .text + +ENTRY(at91_slow_clock) + /* Save registers on stack */ + stmfd sp!, {r0 - r12, lr} + + /* + * Register usage: + * R1 = Base address of AT91_PMC + * R2 = Base address of AT91_SDRAMC (or AT91_SYS on AT91RM9200) + * R3 = temporary register + * R4 = temporary register + */ + ldr r1, .at91_va_base_pmc + ldr r2, .at91_va_base_sdramc + + /* Drain write buffer */ + mcr p15, 0, r0, c7, c10, 4 + +#ifdef CONFIG_ARCH_AT91RM9200 + /* Put SDRAM in self-refresh mode */ + mov r3, #1 + str r3, [r2, #AT91_SDRAMC_SRR] +#elif defined(CONFIG_ARCH_AT91CAP9) + /* Enable SDRAM self-refresh mode */ + ldr r3, [r2, #AT91_DDRSDRC_LPR - AT91_DDRSDRC] + str r3, .saved_sam9_lpr + + mov r3, #AT91_DDRSDRC_LPCB_SELF_REFRESH + str r3, [r2, #AT91_DDRSDRC_LPR - AT91_DDRSDRC] +#else + /* Enable SDRAM self-refresh mode */ + ldr r3, [r2, #AT91_SDRAMC_LPR - AT91_SDRAMC] + str r3, .saved_sam9_lpr + + mov r3, #AT91_SDRAMC_LPCB_SELF_REFRESH + str r3, [r2, #AT91_SDRAMC_LPR - AT91_SDRAMC] +#endif + + /* Save Master clock setting */ + ldr r3, [r1, #(AT91_PMC_MCKR - AT91_PMC)] + str r3, .saved_mckr + + /* + * Set the Master clock source to slow clock + */ + bic r3, r3, #AT91_PMC_CSS + str r3, [r1, #(AT91_PMC_MCKR - AT91_PMC)] + + wait_mckrdy + +#ifdef SLOWDOWN_MASTER_CLOCK + /* + * Set the Master Clock PRES and MDIV fields. + * + * See AT91RM9200 errata #27 and #28 for details. + */ + mov r3, #0 + str r3, [r1, #(AT91_PMC_MCKR - AT91_PMC)] + + wait_mckrdy +#endif + + /* Save PLLA setting and disable it */ + ldr r3, [r1, #(AT91_CKGR_PLLAR - AT91_PMC)] + str r3, .saved_pllar + + mov r3, #AT91_PMC_PLLCOUNT + orr r3, r3, #(1 << 29) /* bit 29 always set */ + str r3, [r1, #(AT91_CKGR_PLLAR - AT91_PMC)] + + wait_pllalock + + /* Save PLLB setting and disable it */ + ldr r3, [r1, #(AT91_CKGR_PLLBR - AT91_PMC)] + str r3, .saved_pllbr + + mov r3, #AT91_PMC_PLLCOUNT + str r3, [r1, #(AT91_CKGR_PLLBR - AT91_PMC)] + + wait_pllblock + + /* Turn off the main oscillator */ + ldr r3, [r1, #(AT91_CKGR_MOR - AT91_PMC)] + bic r3, r3, #AT91_PMC_MOSCEN + str r3, [r1, #(AT91_CKGR_MOR - AT91_PMC)] + + /* Wait for interrupt */ + mcr p15, 0, r0, c7, c0, 4 + + /* Turn on the main oscillator */ + ldr r3, [r1, #(AT91_CKGR_MOR - AT91_PMC)] + orr r3, r3, #AT91_PMC_MOSCEN + str r3, [r1, #(AT91_CKGR_MOR - AT91_PMC)] + + wait_moscrdy + + /* Restore PLLB setting */ + ldr r3, .saved_pllbr + str r3, [r1, #(AT91_CKGR_PLLBR - AT91_PMC)] + + wait_pllblock + + /* Restore PLLA setting */ + ldr r3, .saved_pllar + str r3, [r1, #(AT91_CKGR_PLLAR - AT91_PMC)] + + wait_pllalock + +#ifdef SLOWDOWN_MASTER_CLOCK + /* + * First set PRES if it was not 0, + * than set CSS and MDIV fields. + * + * See AT91RM9200 errata #27 and #28 for details. + */ + ldr r3, .saved_mckr + tst r3, #AT91_PMC_PRES + beq 2f + and r3, r3, #AT91_PMC_PRES + str r3, [r1, #(AT91_PMC_MCKR - AT91_PMC)] + + wait_mckrdy +#endif + + /* + * Restore master clock setting + */ +2: ldr r3, .saved_mckr + str r3, [r1, #(AT91_PMC_MCKR - AT91_PMC)] + + wait_mckrdy + +#ifdef CONFIG_ARCH_AT91RM9200 + /* Do nothing - self-refresh is automatically disabled. */ +#elif defined(CONFIG_ARCH_AT91CAP9) + /* Restore LPR on AT91CAP9 */ + ldr r3, .saved_sam9_lpr + str r3, [r2, #AT91_DDRSDRC_LPR - AT91_DDRSDRC] +#else + /* Restore LPR on AT91SAM9 */ + ldr r3, .saved_sam9_lpr + str r3, [r2, #AT91_SDRAMC_LPR - AT91_SDRAMC] +#endif + + /* Restore registers, and return */ + ldmfd sp!, {r0 - r12, pc} + + +.saved_mckr: + .word 0 + +.saved_pllar: + .word 0 + +.saved_pllbr: + .word 0 + +.saved_sam9_lpr: + .word 0 + +.at91_va_base_pmc: + .word AT91_VA_BASE_SYS + AT91_PMC + +#ifdef CONFIG_ARCH_AT91RM9200 +.at91_va_base_sdramc: + .word AT91_VA_BASE_SYS +#elif defined(CONFIG_ARCH_AT91CAP9) +.at91_va_base_sdramc: + .word AT91_VA_BASE_SYS + AT91_DDRSDRC +#else +.at91_va_base_sdramc: + .word AT91_VA_BASE_SYS + AT91_SDRAMC +#endif + +ENTRY(at91_slow_clock_sz) + .word .-at91_slow_clock |