[PATCH v3 2/4] ARM: OMAP2+: Introduce low-level suspend code for AM43XX

[Dave Gerlach]

Although similar to AM33XX, introduce a new low-level asm file for
suspend containing new context save and restore paths for EMIF and l2
cache disabling and enabling.

Signed-off-by: Dave Gerlach <d-gerlach@xxxxxx>
---
v2->v3:
* Reverse the order of entering self refresh and saving context so that
  we save the exact state of the emif at suspend time.

 arch/arm/mach-omap2/sleep43xx.S | 394 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 394 insertions(+)
 create mode 100644 arch/arm/mach-omap2/sleep43xx.S

diff --git a/arch/arm/mach-omap2/sleep43xx.S b/arch/arm/mach-omap2/sleep43xx.S
new file mode 100644
index 000000000000..fa80961672f6
--- /dev/null
+++ b/arch/arm/mach-omap2/sleep43xx.S
@@ -0,0 +1,394 @@
+/*
+ * Low level suspend code for AM43XX SoCs
+ *
+ * Copyright (C) 2013-2017 Texas Instruments Incorporated - http://www.ti.com/
+ *	Dave Gerlach, Vaibhav Bedia
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/linkage.h>
+#include <linux/ti-emif-sram.h>
+
+#include <asm/asm-offsets.h>
+#include <asm/assembler.h>
+#include <asm/hardware/cache-l2x0.h>
+#include <asm/memory.h>
+
+#include "cm33xx.h"
+#include "common.h"
+#include "iomap.h"
+#include "omap-secure.h"
+#include "omap44xx.h"
+#include "prm33xx.h"
+#include "prcm43xx.h"
+
+#define AM33XX_CM_CLKCTRL_MODULESTATE_DISABLED		0x00030000
+#define AM33XX_CM_CLKCTRL_MODULEMODE_DISABLE		0x0003
+#define AM33XX_CM_CLKCTRL_MODULEMODE_ENABLE		0x0002
+
+#define AM43XX_EMIF_POWEROFF_ENABLE			0x1
+#define AM43XX_EMIF_POWEROFF_DISABLE			0x0
+
+#define AM43XX_CM_CLKSTCTRL_CLKTRCTRL_SW_SLEEP		0x1
+#define AM43XX_CM_CLKSTCTRL_CLKTRCTRL_HW_AUTO		0x3
+
+#define AM43XX_CM_BASE					0x44DF0000
+
+#define AM43XX_CM_REGADDR(inst, reg)                           \
+       AM33XX_L4_WK_IO_ADDRESS(AM43XX_CM_BASE + (inst) + (reg))
+
+#define AM43XX_CM_MPU_CLKSTCTRL AM43XX_CM_REGADDR(AM43XX_CM_MPU_INST, \
+					AM43XX_CM_MPU_MPU_CDOFFS)
+#define AM43XX_CM_MPU_MPU_CLKCTRL AM43XX_CM_REGADDR(AM43XX_CM_MPU_INST, \
+					AM43XX_CM_MPU_MPU_CLKCTRL_OFFSET)
+#define AM43XX_CM_PER_EMIF_CLKCTRL  AM43XX_CM_REGADDR(AM43XX_CM_PER_INST, \
+					AM43XX_CM_PER_EMIF_CLKCTRL_OFFSET)
+#define AM43XX_PRM_EMIF_CTRL_OFFSET			0x0030
+
+	.arm
+	.align 3
+
+ENTRY(am43xx_do_wfi)
+	stmfd	sp!, {r4 - r11, lr}	@ save registers on stack
+
+	/* Retrieve l2 cache virt address BEFORE we shut off EMIF */
+	ldr	r1, get_l2cache_base
+	blx	r1
+	mov	r8, r0
+
+	/*
+	 * Flush all data from the L1 and L2 data cache before disabling
+	 * SCTLR.C bit.
+	 */
+	ldr	r1, kernel_flush
+	blx	r1
+
+	/*
+	 * Clear the SCTLR.C bit to prevent further data cache
+	 * allocation. Clearing SCTLR.C would make all the data accesses
+	 * strongly ordered and would not hit the cache.
+	 */
+	mrc	p15, 0, r0, c1, c0, 0
+	bic	r0, r0, #(1 << 2)	@ Disable the C bit
+	mcr	p15, 0, r0, c1, c0, 0
+	isb
+	dsb
+
+	/*
+	 * Invalidate L1 and L2 data cache.
+	 */
+	ldr	r1, kernel_flush
+	blx	r1
+
+#ifdef CONFIG_CACHE_L2X0
+	/*
+	 * Clean and invalidate the L2 cache.
+	 */
+#ifdef CONFIG_PL310_ERRATA_727915
+	mov	r0, #0x03
+	mov	r12, #OMAP4_MON_L2X0_DBG_CTRL_INDEX
+	dsb
+	smc	#0
+	dsb
+#endif
+	mov	r0, r8
+	adr	r4, am43xx_pm_ro_sram_data
+	ldr	r3, [r4, #AMX3_PM_RO_SRAM_DATA_VIRT_OFFSET]
+
+	mov	r2, r0
+	ldr	r0, [r2, #L2X0_AUX_CTRL]
+	str	r0, [r3, #AMX3_PM_L2_AUX_CTRL_VAL_OFFSET]
+	ldr	r0, [r2, #L310_PREFETCH_CTRL]
+	str	r0, [r3, #AMX3_PM_L2_PREFETCH_CTRL_VAL_OFFSET]
+
+	ldr	r0, l2_val
+	str	r0, [r2, #L2X0_CLEAN_INV_WAY]
+wait:
+	ldr	r0, [r2, #L2X0_CLEAN_INV_WAY]
+	ldr	r1, l2_val
+	ands	r0, r0, r1
+	bne	wait
+#ifdef CONFIG_PL310_ERRATA_727915
+	mov	r0, #0x00
+	mov	r12, #OMAP4_MON_L2X0_DBG_CTRL_INDEX
+	dsb
+	smc	#0
+	dsb
+#endif
+l2x_sync:
+	mov	r0, r8
+	mov	r2, r0
+	mov	r0, #0x0
+	str	r0, [r2, #L2X0_CACHE_SYNC]
+sync:
+	ldr	r0, [r2, #L2X0_CACHE_SYNC]
+	ands	r0, r0, #0x1
+	bne	sync
+#endif
+
+	adr     r9, am43xx_emif_sram_table
+
+	ldr     r3, [r9, #EMIF_PM_ENTER_SR_OFFSET]
+	blx     r3
+
+	ldr     r3, [r9, #EMIF_PM_SAVE_CONTEXT_OFFSET]
+	blx     r3
+
+	/* Disable EMIF */
+	ldr	r1, am43xx_virt_emif_clkctrl
+	ldr	r2, [r1]
+	bic	r2, r2, #AM33XX_CM_CLKCTRL_MODULEMODE_DISABLE
+	str	r2, [r1]
+
+wait_emif_disable:
+	ldr	r2, [r1]
+	mov	r3, #AM33XX_CM_CLKCTRL_MODULESTATE_DISABLED
+	cmp	r2, r3
+	bne	wait_emif_disable
+
+	/*
+	 * For the MPU WFI to be registered as an interrupt
+	 * to WKUP_M3, MPU_CLKCTRL.MODULEMODE needs to be set
+	 * to DISABLED
+	 */
+	ldr	r1, am43xx_virt_mpu_clkctrl
+	ldr	r2, [r1]
+	bic	r2, r2, #AM33XX_CM_CLKCTRL_MODULEMODE_DISABLE
+	str	r2, [r1]
+
+	/*
+	 * Put MPU CLKDM to SW_SLEEP
+	 */
+	ldr	r1, am43xx_virt_mpu_clkstctrl
+	mov	r2, #AM43XX_CM_CLKSTCTRL_CLKTRCTRL_SW_SLEEP
+	str	r2, [r1]
+
+	/*
+	 * Execute a barrier instruction to ensure that all cache,
+	 * TLB and branch predictor maintenance operations issued
+	 * have completed.
+	 */
+	dsb
+	dmb
+
+	/*
+	 * Execute a WFI instruction and wait until the
+	 * STANDBYWFI output is asserted to indicate that the
+	 * CPU is in idle and low power state. CPU can specualatively
+	 * prefetch the instructions so add NOPs after WFI. Sixteen
+	 * NOPs as per Cortex-A9 pipeline.
+	 */
+	wfi
+
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+
+	/* We come here in case of an abort due to a late interrupt */
+	ldr	r1, am43xx_virt_mpu_clkstctrl
+	mov	r2, #AM43XX_CM_CLKSTCTRL_CLKTRCTRL_HW_AUTO
+	str	r2, [r1]
+
+	/* Set MPU_CLKCTRL.MODULEMODE back to ENABLE */
+	ldr	r1, am43xx_virt_mpu_clkctrl
+	mov	r2, #AM33XX_CM_CLKCTRL_MODULEMODE_ENABLE
+	str	r2, [r1]
+
+	/* Re-enable EMIF */
+	ldr	r1, am43xx_virt_emif_clkctrl
+	mov	r2, #AM33XX_CM_CLKCTRL_MODULEMODE_ENABLE
+	str	r2, [r1]
+wait_emif_enable:
+	ldr	r3, [r1]
+	cmp	r2, r3
+	bne	wait_emif_enable
+
+	/*
+	 * Set SCTLR.C bit to allow data cache allocation
+	 */
+	mrc	p15, 0, r0, c1, c0, 0
+	orr	r0, r0, #(1 << 2)	@ Enable the C bit
+	mcr	p15, 0, r0, c1, c0, 0
+	isb
+
+	ldr     r1, [r9, #EMIF_PM_ABORT_SR_OFFSET]
+	blx     r1
+
+	/* Let the suspend code know about the abort */
+	mov	r0, #1
+	ldmfd	sp!, {r4 - r11, pc}	@ restore regs and return
+ENDPROC(am43xx_do_wfi)
+
+	.align
+ENTRY(am43xx_resume_offset)
+	.word . - am43xx_do_wfi
+
+ENTRY(am43xx_resume_from_deep_sleep)
+	/* Set MPU CLKSTCTRL to HW AUTO so that CPUidle works properly */
+	ldr	r1, am43xx_virt_mpu_clkstctrl
+	mov	r2, #AM43XX_CM_CLKSTCTRL_CLKTRCTRL_HW_AUTO
+	str	r2, [r1]
+
+	/* For AM43xx, use EMIF power down until context is restored */
+	ldr	r2, am43xx_phys_emif_poweroff
+	mov	r1, #AM43XX_EMIF_POWEROFF_ENABLE
+	str	r1, [r2, #0x0]
+
+	/* Re-enable EMIF */
+	ldr	r1, am43xx_phys_emif_clkctrl
+	mov	r2, #AM33XX_CM_CLKCTRL_MODULEMODE_ENABLE
+	str	r2, [r1]
+wait_emif_enable1:
+	ldr	r3, [r1]
+	cmp	r2, r3
+	bne	wait_emif_enable1
+
+	adr     r9, am43xx_emif_sram_table
+
+	ldr     r1, [r9, #EMIF_PM_RESTORE_CONTEXT_OFFSET]
+	blx     r1
+
+	ldr     r1, [r9, #EMIF_PM_EXIT_SR_OFFSET]
+	blx     r1
+
+	ldr     r2, am43xx_phys_emif_poweroff
+	mov     r1, #AM43XX_EMIF_POWEROFF_DISABLE
+	str     r1, [r2, #0x0]
+
+#ifdef CONFIG_CACHE_L2X0
+	ldr	r2, l2_cache_base
+	ldr	r0, [r2, #L2X0_CTRL]
+	and	r0, #0x0f
+	cmp	r0, #1
+	beq	skip_l2en			@ Skip if already enabled
+
+	adr	r4, am43xx_pm_ro_sram_data
+	ldr	r3, [r4, #AMX3_PM_RO_SRAM_DATA_PHYS_OFFSET]
+	ldr     r0, [r3, #AMX3_PM_L2_PREFETCH_CTRL_VAL_OFFSET]
+
+	ldr	r12, l2_smc1
+	dsb
+	smc	#0
+	dsb
+set_aux_ctrl:
+	ldr     r0, [r3, #AMX3_PM_L2_AUX_CTRL_VAL_OFFSET]
+	ldr	r12, l2_smc2
+	dsb
+	smc	#0
+	dsb
+
+	/* L2 invalidate on resume */
+	ldr	r0, l2_val
+	ldr	r2, l2_cache_base
+	str	r0, [r2, #L2X0_INV_WAY]
+wait2:
+	ldr	r0, [r2, #L2X0_INV_WAY]
+	ldr	r1, l2_val
+	ands	r0, r0, r1
+	bne	wait2
+#ifdef CONFIG_PL310_ERRATA_727915
+	mov	r0, #0x00
+	mov	r12, #OMAP4_MON_L2X0_DBG_CTRL_INDEX
+	dsb
+	smc	#0
+	dsb
+#endif
+l2x_sync2:
+	ldr	r2, l2_cache_base
+	mov	r0, #0x0
+	str	r0, [r2, #L2X0_CACHE_SYNC]
+sync2:
+	ldr	r0, [r2, #L2X0_CACHE_SYNC]
+	ands	r0, r0, #0x1
+	bne	sync2
+
+	mov	r0, #0x1
+	ldr	r12, l2_smc3
+	dsb
+	smc	#0
+	dsb
+#endif
+skip_l2en:
+	/* We are back. Branch to the common CPU resume routine */
+	mov	r0, #0
+	ldr	pc, resume_addr
+ENDPROC(am43xx_resume_from_deep_sleep)
+
+/*
+ * Local variables
+ */
+	.align
+resume_addr:
+	.word	cpu_resume - PAGE_OFFSET + 0x80000000
+get_l2cache_base:
+	.word	omap4_get_l2cache_base
+kernel_flush:
+	.word   v7_flush_dcache_all
+ddr_start:
+	.word	PAGE_OFFSET
+
+am43xx_phys_emif_poweroff:
+	.word   (AM43XX_CM_BASE + AM43XX_PRM_DEVICE_INST + \
+		 AM43XX_PRM_EMIF_CTRL_OFFSET)
+am43xx_virt_mpu_clkstctrl:
+	.word	(AM43XX_CM_MPU_CLKSTCTRL)
+am43xx_virt_mpu_clkctrl:
+	.word	(AM43XX_CM_MPU_MPU_CLKCTRL)
+am43xx_virt_emif_clkctrl:
+	.word	(AM43XX_CM_PER_EMIF_CLKCTRL)
+am43xx_phys_emif_clkctrl:
+	.word	(AM43XX_CM_BASE + AM43XX_CM_PER_INST + \
+		 AM43XX_CM_PER_EMIF_CLKCTRL_OFFSET)
+
+/* L2 cache related defines for AM437x */
+l2_cache_base:
+	.word	OMAP44XX_L2CACHE_BASE
+l2_smc1:
+	.word	OMAP4_MON_L2X0_PREFETCH_INDEX
+l2_smc2:
+	.word	OMAP4_MON_L2X0_AUXCTRL_INDEX
+l2_smc3:
+	.word	OMAP4_MON_L2X0_CTRL_INDEX
+l2_val:
+	.word	0xffff
+
+.align 3
+/* DDR related defines */
+ENTRY(am43xx_emif_sram_table)
+	.space EMIF_PM_FUNCTIONS_SIZE
+
+ENTRY(am43xx_pm_sram)
+.word am43xx_do_wfi
+.word am43xx_do_wfi_sz
+.word am43xx_resume_offset
+.word am43xx_emif_sram_table
+.word am43xx_pm_ro_sram_data
+
+.align 3
+
+ENTRY(am43xx_pm_ro_sram_data)
+	.space AMX3_PM_RO_SRAM_DATA_SIZE
+
+ENTRY(am43xx_do_wfi_sz)
+	.word	. - am43xx_do_wfi
-- 
2.13.0