memory: ti-emif-sram: introduce relocatable suspend/resume handlers

Certain SoCs like Texas Instruments AM335x and AM437x require parts
of the EMIF PM code to run late in the suspend sequence from SRAM,
such as saving and restoring the EMIF context and placing the memory
into self-refresh.

One requirement for these SoCs to suspend and enter its lowest power
mode, called DeepSleep0, is that the PER power domain must be shut off.
Because the EMIF (DDR Controller) resides within this power domain, it
will lose context during a suspend operation, so we must save it so we
can restore once we resume. However, we cannot execute this code from
external memory, as it is not available at this point, so the code must
be executed late in the suspend path from SRAM.

This patch introduces a ti-emif-sram driver that includes several
functions written in ARM ASM that are relocatable so the PM SRAM
code can use them. It also allocates a region of writable SRAM to
be used by the code running in the executable region of SRAM to save
and restore the EMIF context. It can export a table containing the
absolute addresses of the available PM functions so that other SRAM
code can branch to them. This code is required for suspend/resume on
AM335x and AM437x to work.

In addition to this, to be able to share data structures between C and
the ti-emif-sram-pm assembly code, we can automatically generate all of
the C struct member offsets and sizes as macros by processing
emif-asm-offsets.c into assembly code and then extracting the relevant
data as is done for the generated platform asm-offsets.h files.

Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Dave Gerlach <d-gerlach@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>

7 files changed, 791 insertions, 0 deletions

diff --git a/drivers/memory/Kconfig b/drivers/memory/Kconfig
index ffc350258041..19a0e83f260d 100644
--- a/drivers/memory/Kconfig
+++ b/drivers/memory/Kconfig
@@ -84,6 +84,16 @@ config OMAP_GPMC_DEBUG
 	  bootloader or else the GPMC timings won't be identical with the
 	  bootloader timings.
 
+config TI_EMIF_SRAM
+	tristate "Texas Instruments EMIF SRAM driver"
+	depends on (SOC_AM33XX || SOC_AM43XX) && SRAM
+	help
+	  This driver is for the EMIF module available on Texas Instruments
+	  AM33XX and AM43XX SoCs and is required for PM. Certain parts of
+	  the EMIF PM code must run from on-chip SRAM late in the suspend
+	  sequence so this driver provides several relocatable PM functions
+	  for the SoC PM code to use.
+
 config MVEBU_DEVBUS
 	bool "Marvell EBU Device Bus Controller"
 	default y
diff --git a/drivers/memory/Makefile b/drivers/memory/Makefile
index 929a601d4cd1..66f55240830e 100644
--- a/drivers/memory/Makefile
+++ b/drivers/memory/Makefile
@@ -23,3 +23,11 @@ obj-$(CONFIG_DA8XX_DDRCTL)	+= da8xx-ddrctl.o
 
 obj-$(CONFIG_SAMSUNG_MC)	+= samsung/
 obj-$(CONFIG_TEGRA_MC)		+= tegra/
+obj-$(CONFIG_TI_EMIF_SRAM)	+= ti-emif-sram.o
+ti-emif-sram-objs		:= ti-emif-pm.o ti-emif-sram-pm.o
+
+AFLAGS_ti-emif-sram-pm.o	:=-Wa,-march=armv7-a
+
+include drivers/memory/Makefile.asm-offsets
+
+drivers/memory/ti-emif-sram-pm.o: include/generated/ti-emif-asm-offsets.h
diff --git a/drivers/memory/Makefile.asm-offsets b/drivers/memory/Makefile.asm-offsets
new file mode 100644
index 000000000000..843ff60ccb5a
--- /dev/null
+++ b/drivers/memory/Makefile.asm-offsets
@@ -0,0 +1,5 @@
+drivers/memory/emif-asm-offsets.s: drivers/memory/emif-asm-offsets.c
+	$(call if_changed_dep,cc_s_c)
+
+include/generated/ti-emif-asm-offsets.h: drivers/memory/emif-asm-offsets.s FORCE
+	$(call filechk,offsets,__TI_EMIF_ASM_OFFSETS_H__)
diff --git a/drivers/memory/emif-asm-offsets.c b/drivers/memory/emif-asm-offsets.c
new file mode 100644
index 000000000000..71a89d5d3efd
--- /dev/null
+++ b/drivers/memory/emif-asm-offsets.c
@@ -0,0 +1,92 @@
+/*
+ * TI AM33XX EMIF PM Assembly Offsets
+ *
+ * Copyright (C) 2016-2017 Texas Instruments Inc.
+ *
+ * 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/ti-emif-sram.h>
+
+int main(void)
+{
+	DEFINE(EMIF_SDCFG_VAL_OFFSET,
+	       offsetof(struct emif_regs_amx3, emif_sdcfg_val));
+	DEFINE(EMIF_TIMING1_VAL_OFFSET,
+	       offsetof(struct emif_regs_amx3, emif_timing1_val));
+	DEFINE(EMIF_TIMING2_VAL_OFFSET,
+	       offsetof(struct emif_regs_amx3, emif_timing2_val));
+	DEFINE(EMIF_TIMING3_VAL_OFFSET,
+	       offsetof(struct emif_regs_amx3, emif_timing3_val));
+	DEFINE(EMIF_REF_CTRL_VAL_OFFSET,
+	       offsetof(struct emif_regs_amx3, emif_ref_ctrl_val));
+	DEFINE(EMIF_ZQCFG_VAL_OFFSET,
+	       offsetof(struct emif_regs_amx3, emif_zqcfg_val));
+	DEFINE(EMIF_PMCR_VAL_OFFSET,
+	       offsetof(struct emif_regs_amx3, emif_pmcr_val));
+	DEFINE(EMIF_PMCR_SHDW_VAL_OFFSET,
+	       offsetof(struct emif_regs_amx3, emif_pmcr_shdw_val));
+	DEFINE(EMIF_RD_WR_LEVEL_RAMP_CTRL_OFFSET,
+	       offsetof(struct emif_regs_amx3, emif_rd_wr_level_ramp_ctrl));
+	DEFINE(EMIF_RD_WR_EXEC_THRESH_OFFSET,
+	       offsetof(struct emif_regs_amx3, emif_rd_wr_exec_thresh));
+	DEFINE(EMIF_COS_CONFIG_OFFSET,
+	       offsetof(struct emif_regs_amx3, emif_cos_config));
+	DEFINE(EMIF_PRIORITY_TO_COS_MAPPING_OFFSET,
+	       offsetof(struct emif_regs_amx3, emif_priority_to_cos_mapping));
+	DEFINE(EMIF_CONNECT_ID_SERV_1_MAP_OFFSET,
+	       offsetof(struct emif_regs_amx3, emif_connect_id_serv_1_map));
+	DEFINE(EMIF_CONNECT_ID_SERV_2_MAP_OFFSET,
+	       offsetof(struct emif_regs_amx3, emif_connect_id_serv_2_map));
+	DEFINE(EMIF_OCP_CONFIG_VAL_OFFSET,
+	       offsetof(struct emif_regs_amx3, emif_ocp_config_val));
+	DEFINE(EMIF_LPDDR2_NVM_TIM_OFFSET,
+	       offsetof(struct emif_regs_amx3, emif_lpddr2_nvm_tim));
+	DEFINE(EMIF_LPDDR2_NVM_TIM_SHDW_OFFSET,
+	       offsetof(struct emif_regs_amx3, emif_lpddr2_nvm_tim_shdw));
+	DEFINE(EMIF_DLL_CALIB_CTRL_VAL_OFFSET,
+	       offsetof(struct emif_regs_amx3, emif_dll_calib_ctrl_val));
+	DEFINE(EMIF_DLL_CALIB_CTRL_VAL_SHDW_OFFSET,
+	       offsetof(struct emif_regs_amx3, emif_dll_calib_ctrl_val_shdw));
+	DEFINE(EMIF_DDR_PHY_CTLR_1_OFFSET,
+	       offsetof(struct emif_regs_amx3, emif_ddr_phy_ctlr_1));
+	DEFINE(EMIF_EXT_PHY_CTRL_VALS_OFFSET,
+	       offsetof(struct emif_regs_amx3, emif_ext_phy_ctrl_vals));
+	DEFINE(EMIF_REGS_AMX3_SIZE, sizeof(struct emif_regs_amx3));
+
+	BLANK();
+
+	DEFINE(EMIF_PM_BASE_ADDR_VIRT_OFFSET,
+	       offsetof(struct ti_emif_pm_data, ti_emif_base_addr_virt));
+	DEFINE(EMIF_PM_BASE_ADDR_PHYS_OFFSET,
+	       offsetof(struct ti_emif_pm_data, ti_emif_base_addr_phys));
+	DEFINE(EMIF_PM_CONFIG_OFFSET,
+	       offsetof(struct ti_emif_pm_data, ti_emif_sram_config));
+	DEFINE(EMIF_PM_REGS_VIRT_OFFSET,
+	       offsetof(struct ti_emif_pm_data, regs_virt));
+	DEFINE(EMIF_PM_REGS_PHYS_OFFSET,
+	       offsetof(struct ti_emif_pm_data, regs_phys));
+	DEFINE(EMIF_PM_DATA_SIZE, sizeof(struct ti_emif_pm_data));
+
+	BLANK();
+
+	DEFINE(EMIF_PM_SAVE_CONTEXT_OFFSET,
+	       offsetof(struct ti_emif_pm_functions, save_context));
+	DEFINE(EMIF_PM_RESTORE_CONTEXT_OFFSET,
+	       offsetof(struct ti_emif_pm_functions, restore_context));
+	DEFINE(EMIF_PM_ENTER_SR_OFFSET,
+	       offsetof(struct ti_emif_pm_functions, enter_sr));
+	DEFINE(EMIF_PM_EXIT_SR_OFFSET,
+	       offsetof(struct ti_emif_pm_functions, exit_sr));
+	DEFINE(EMIF_PM_ABORT_SR_OFFSET,
+	       offsetof(struct ti_emif_pm_functions, abort_sr));
+	DEFINE(EMIF_PM_FUNCTIONS_SIZE, sizeof(struct ti_emif_pm_functions));
+
+	return 0;
+}
diff --git a/drivers/memory/emif.h b/drivers/memory/emif.h
index bfe08bae961a..9e9f8037955d 100644
--- a/drivers/memory/emif.h
+++ b/drivers/memory/emif.h
@@ -555,6 +555,9 @@
 #define READ_LATENCY_SHDW_SHIFT				0
 #define READ_LATENCY_SHDW_MASK				(0x1f << 0)
 
+#define EMIF_SRAM_AM33_REG_LAYOUT			0x00000000
+#define EMIF_SRAM_AM43_REG_LAYOUT			0x00000001
+
 #ifndef __ASSEMBLY__
 /*
  * Structure containing shadow of important registers in EMIF
@@ -585,5 +588,19 @@ struct emif_regs {
 	u32 ext_phy_ctrl_3_shdw;
 	u32 ext_phy_ctrl_4_shdw;
 };
+
+struct ti_emif_pm_functions;
+
+extern unsigned int ti_emif_sram;
+extern unsigned int ti_emif_sram_sz;
+extern struct ti_emif_pm_data ti_emif_pm_sram_data;
+extern struct emif_regs_amx3 ti_emif_regs_amx3;
+
+void ti_emif_save_context(void);
+void ti_emif_restore_context(void);
+void ti_emif_enter_sr(void);
+void ti_emif_exit_sr(void);
+void ti_emif_abort_sr(void);
+
 #endif /* __ASSEMBLY__ */
 #endif /* __EMIF_H */
diff --git a/drivers/memory/ti-emif-pm.c b/drivers/memory/ti-emif-pm.c
new file mode 100644
index 000000000000..4ea1514fb9b2
--- /dev/null
+++ b/drivers/memory/ti-emif-pm.c
@@ -0,0 +1,325 @@
+/*
+ * TI AM33XX SRAM EMIF Driver
+ *
+ * Copyright (C) 2016-2017 Texas Instruments Inc.
+ *	Dave Gerlach
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that 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.
+ */
+
+#include <linux/err.h>
+#include <linux/genalloc.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/sram.h>
+#include <linux/ti-emif-sram.h>
+
+#include "emif.h"
+
+#define TI_EMIF_SRAM_SYMBOL_OFFSET(sym) ((unsigned long)(sym) - \
+					 (unsigned long)&ti_emif_sram)
+
+#define EMIF_POWER_MGMT_WAIT_SELF_REFRESH_8192_CYCLES		0x00a0
+
+struct ti_emif_data {
+	phys_addr_t ti_emif_sram_phys;
+	phys_addr_t ti_emif_sram_data_phys;
+	unsigned long ti_emif_sram_virt;
+	unsigned long ti_emif_sram_data_virt;
+	struct gen_pool *sram_pool_code;
+	struct gen_pool	*sram_pool_data;
+	struct ti_emif_pm_data pm_data;
+	struct ti_emif_pm_functions pm_functions;
+};
+
+static struct ti_emif_data *emif_instance;
+
+static u32 sram_suspend_address(struct ti_emif_data *emif_data,
+				unsigned long addr)
+{
+	return (emif_data->ti_emif_sram_virt +
+		TI_EMIF_SRAM_SYMBOL_OFFSET(addr));
+}
+
+static phys_addr_t sram_resume_address(struct ti_emif_data *emif_data,
+				       unsigned long addr)
+{
+	return ((unsigned long)emif_data->ti_emif_sram_phys +
+		TI_EMIF_SRAM_SYMBOL_OFFSET(addr));
+}
+
+static void ti_emif_free_sram(struct ti_emif_data *emif_data)
+{
+	gen_pool_free(emif_data->sram_pool_code, emif_data->ti_emif_sram_virt,
+		      ti_emif_sram_sz);
+	gen_pool_free(emif_data->sram_pool_data,
+		      emif_data->ti_emif_sram_data_virt,
+		      sizeof(struct emif_regs_amx3));
+}
+
+static int ti_emif_alloc_sram(struct device *dev,
+			      struct ti_emif_data *emif_data)
+{
+	struct device_node *np = dev->of_node;
+	int ret;
+
+	emif_data->sram_pool_code = of_gen_pool_get(np, "sram", 0);
+	if (!emif_data->sram_pool_code) {
+		dev_err(dev, "Unable to get sram pool for ocmcram code\n");
+		return -ENODEV;
+	}
+
+	emif_data->ti_emif_sram_virt =
+			gen_pool_alloc(emif_data->sram_pool_code,
+				       ti_emif_sram_sz);
+	if (!emif_data->ti_emif_sram_virt) {
+		dev_err(dev, "Unable to allocate code memory from ocmcram\n");
+		return -ENOMEM;
+	}
+
+	/* Save physical address to calculate resume offset during pm init */
+	emif_data->ti_emif_sram_phys =
+			gen_pool_virt_to_phys(emif_data->sram_pool_code,
+					      emif_data->ti_emif_sram_virt);
+
+	/* Get sram pool for data section and allocate space */
+	emif_data->sram_pool_data = of_gen_pool_get(np, "sram", 1);
+	if (!emif_data->sram_pool_data) {
+		dev_err(dev, "Unable to get sram pool for ocmcram data\n");
+		ret = -ENODEV;
+		goto err_free_sram_code;
+	}
+
+	emif_data->ti_emif_sram_data_virt =
+				gen_pool_alloc(emif_data->sram_pool_data,
+					       sizeof(struct emif_regs_amx3));
+	if (!emif_data->ti_emif_sram_data_virt) {
+		dev_err(dev, "Unable to allocate data memory from ocmcram\n");
+		ret = -ENOMEM;
+		goto err_free_sram_code;
+	}
+
+	/* Save physical address to calculate resume offset during pm init */
+	emif_data->ti_emif_sram_data_phys =
+		gen_pool_virt_to_phys(emif_data->sram_pool_data,
+				      emif_data->ti_emif_sram_data_virt);
+	/*
+	 * These functions are called during suspend path while MMU is
+	 * still on so add virtual base to offset for absolute address
+	 */
+	emif_data->pm_functions.save_context =
+		sram_suspend_address(emif_data,
+				     (unsigned long)ti_emif_save_context);
+	emif_data->pm_functions.enter_sr =
+		sram_suspend_address(emif_data,
+				     (unsigned long)ti_emif_enter_sr);
+	emif_data->pm_functions.abort_sr =
+		sram_suspend_address(emif_data,
+				     (unsigned long)ti_emif_abort_sr);
+
+	/*
+	 * These are called during resume path when MMU is not enabled
+	 * so physical address is used instead
+	 */
+	emif_data->pm_functions.restore_context =
+		sram_resume_address(emif_data,
+				    (unsigned long)ti_emif_restore_context);
+	emif_data->pm_functions.exit_sr =
+		sram_resume_address(emif_data,
+				    (unsigned long)ti_emif_exit_sr);
+
+	emif_data->pm_data.regs_virt =
+		(struct emif_regs_amx3 *)emif_data->ti_emif_sram_data_virt;
+	emif_data->pm_data.regs_phys = emif_data->ti_emif_sram_data_phys;
+
+	return 0;
+
+err_free_sram_code:
+	gen_pool_free(emif_data->sram_pool_code, emif_data->ti_emif_sram_virt,
+		      ti_emif_sram_sz);
+	return ret;
+}
+
+static int ti_emif_push_sram(struct device *dev, struct ti_emif_data *emif_data)
+{
+	void *copy_addr;
+	u32 data_addr;
+
+	copy_addr = sram_exec_copy(emif_data->sram_pool_code,
+				   (void *)emif_data->ti_emif_sram_virt,
+				   &ti_emif_sram, ti_emif_sram_sz);
+	if (!copy_addr) {
+		dev_err(dev, "Cannot copy emif code to sram\n");
+		return -ENODEV;
+	}
+
+	data_addr = sram_suspend_address(emif_data,
+					 (unsigned long)&ti_emif_pm_sram_data);
+	copy_addr = sram_exec_copy(emif_data->sram_pool_code,
+				   (void *)data_addr,
+				   &emif_data->pm_data,
+				   sizeof(emif_data->pm_data));
+	if (!copy_addr) {
+		dev_err(dev, "Cannot copy emif data to code sram\n");
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+/*
+ * Due to Usage Note 3.1.2 "DDR3: JEDEC Compliance for Maximum
+ * Self-Refresh Command Limit" found in AM335x Silicon Errata
+ * (Document SPRZ360F Revised November 2013) we must configure
+ * the self refresh delay timer to 0xA (8192 cycles) to avoid
+ * generating too many refresh command from the EMIF.
+ */
+static void ti_emif_configure_sr_delay(struct ti_emif_data *emif_data)
+{
+	writel(EMIF_POWER_MGMT_WAIT_SELF_REFRESH_8192_CYCLES,
+	       (emif_data->pm_data.ti_emif_base_addr_virt +
+		EMIF_POWER_MANAGEMENT_CONTROL));
+
+	writel(EMIF_POWER_MGMT_WAIT_SELF_REFRESH_8192_CYCLES,
+	       (emif_data->pm_data.ti_emif_base_addr_virt +
+		EMIF_POWER_MANAGEMENT_CTRL_SHDW));
+}
+
+/**
+ * ti_emif_copy_pm_function_table - copy mapping of pm funcs in sram
+ * @sram_pool: pointer to struct gen_pool where dst resides
+ * @dst: void * to address that table should be copied
+ *
+ * Returns 0 if success other error code if table is not available
+ */
+int ti_emif_copy_pm_function_table(struct gen_pool *sram_pool, void *dst)
+{
+	void *copy_addr;
+
+	if (!emif_instance)
+		return -ENODEV;
+
+	copy_addr = sram_exec_copy(sram_pool, dst,
+				   &emif_instance->pm_functions,
+				   sizeof(emif_instance->pm_functions));
+	if (!copy_addr)
+		return -ENODEV;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(ti_emif_copy_pm_function_table);
+
+/**
+ * ti_emif_get_mem_type - return type for memory type in use
+ *
+ * Returns memory type value read from EMIF or error code if fails
+ */
+int ti_emif_get_mem_type(void)
+{
+	unsigned long temp;
+
+	if (!emif_instance)
+		return -ENODEV;
+
+	temp = readl(emif_instance->pm_data.ti_emif_base_addr_virt +
+		     EMIF_SDRAM_CONFIG);
+
+	temp = (temp & SDRAM_TYPE_MASK) >> SDRAM_TYPE_SHIFT;
+	return temp;
+}
+EXPORT_SYMBOL_GPL(ti_emif_get_mem_type);
+
+static const struct of_device_id ti_emif_of_match[] = {
+	{ .compatible = "ti,emif-am3352", .data =
+					(void *)EMIF_SRAM_AM33_REG_LAYOUT, },
+	{ .compatible = "ti,emif-am4372", .data =
+					(void *)EMIF_SRAM_AM43_REG_LAYOUT, },
+	{},
+};
+MODULE_DEVICE_TABLE(of, ti_emif_of_match);
+
+static int ti_emif_probe(struct platform_device *pdev)
+{
+	int ret;
+	struct resource *res;
+	struct device *dev = &pdev->dev;
+	const struct of_device_id *match;
+	struct ti_emif_data *emif_data;
+
+	emif_data = devm_kzalloc(dev, sizeof(*emif_data), GFP_KERNEL);
+	if (!emif_data)
+		return -ENOMEM;
+
+	match = of_match_device(ti_emif_of_match, &pdev->dev);
+	if (!match)
+		return -ENODEV;
+
+	emif_data->pm_data.ti_emif_sram_config = (unsigned long)match->data;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	emif_data->pm_data.ti_emif_base_addr_virt = devm_ioremap_resource(dev,
+									  res);
+	if (IS_ERR(emif_data->pm_data.ti_emif_base_addr_virt)) {
+		dev_err(dev, "could not ioremap emif mem\n");
+		ret = PTR_ERR(emif_data->pm_data.ti_emif_base_addr_virt);
+		return ret;
+	}
+
+	emif_data->pm_data.ti_emif_base_addr_phys = res->start;
+
+	ti_emif_configure_sr_delay(emif_data);
+
+	ret = ti_emif_alloc_sram(dev, emif_data);
+	if (ret)
+		return ret;
+
+	ret = ti_emif_push_sram(dev, emif_data);
+	if (ret)
+		goto fail_free_sram;
+
+	emif_instance = emif_data;
+
+	return 0;
+
+fail_free_sram:
+	ti_emif_free_sram(emif_data);
+
+	return ret;
+}
+
+static int ti_emif_remove(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct ti_emif_data *emif_data = emif_instance;
+
+	emif_instance = NULL;
+
+	ti_emif_free_sram(emif_data);
+
+	return 0;
+}
+
+static struct platform_driver ti_emif_driver = {
+	.probe = ti_emif_probe,
+	.remove = ti_emif_remove,
+	.driver = {
+		.name = KBUILD_MODNAME,
+		.of_match_table = of_match_ptr(ti_emif_of_match),
+	},
+};
+module_platform_driver(ti_emif_driver);
+
+MODULE_AUTHOR("Dave Gerlach <d-gerlach@ti.com>");
+MODULE_DESCRIPTION("Texas Instruments SRAM EMIF driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/memory/ti-emif-sram-pm.S b/drivers/memory/ti-emif-sram-pm.S
new file mode 100644
index 000000000000..a5369181e5c2
--- /dev/null
+++ b/drivers/memory/ti-emif-sram-pm.S
@@ -0,0 +1,334 @@
+/*
+ * Low level PM code for TI EMIF
+ *
+ * Copyright (C) 2016-2017 Texas Instruments Incorporated - http://www.ti.com/
+ *	Dave Gerlach
+ *
+ * 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 <generated/ti-emif-asm-offsets.h>
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+#include <asm/memory.h>
+
+#include "emif.h"
+
+#define EMIF_POWER_MGMT_WAIT_SELF_REFRESH_8192_CYCLES	0x00a0
+#define EMIF_POWER_MGMT_SR_TIMER_MASK			0x00f0
+#define EMIF_POWER_MGMT_SELF_REFRESH_MODE		0x0200
+#define EMIF_POWER_MGMT_SELF_REFRESH_MODE_MASK		0x0700
+
+#define EMIF_SDCFG_TYPE_DDR2				0x2 << SDRAM_TYPE_SHIFT
+#define EMIF_STATUS_READY				0x4
+
+#define AM43XX_EMIF_PHY_CTRL_REG_COUNT                  0x120
+
+#define EMIF_AM437X_REGISTERS				0x1
+
+	.arm
+	.align 3
+
+ENTRY(ti_emif_sram)
+
+/*
+ * void ti_emif_save_context(void)
+ *
+ * Used during suspend to save the context of all required EMIF registers
+ * to local memory if the EMIF is going to lose context during the sleep
+ * transition. Operates on the VIRTUAL address of the EMIF.
+ */
+ENTRY(ti_emif_save_context)
+	stmfd   sp!, {r4 - r11, lr}     @ save registers on stack
+
+	adr	r4, ti_emif_pm_sram_data
+	ldr	r0, [r4, #EMIF_PM_BASE_ADDR_VIRT_OFFSET]
+	ldr	r2, [r4, #EMIF_PM_REGS_VIRT_OFFSET]
+
+	/* Save EMIF configuration */
+	ldr	r1, [r0, #EMIF_SDRAM_CONFIG]
+	str	r1, [r2, #EMIF_SDCFG_VAL_OFFSET]
+
+	ldr	r1, [r0, #EMIF_SDRAM_REFRESH_CONTROL]
+	str	r1, [r2, #EMIF_REF_CTRL_VAL_OFFSET]
+
+	ldr	r1, [r0, #EMIF_SDRAM_TIMING_1]
+	str     r1, [r2, #EMIF_TIMING1_VAL_OFFSET]
+
+	ldr	r1, [r0, #EMIF_SDRAM_TIMING_2]
+	str     r1, [r2, #EMIF_TIMING2_VAL_OFFSET]
+
+	ldr	r1, [r0, #EMIF_SDRAM_TIMING_3]
+	str     r1, [r2, #EMIF_TIMING3_VAL_OFFSET]
+
+	ldr	r1, [r0, #EMIF_POWER_MANAGEMENT_CONTROL]
+	str     r1, [r2, #EMIF_PMCR_VAL_OFFSET]
+
+	ldr	r1, [r0, #EMIF_POWER_MANAGEMENT_CTRL_SHDW]
+	str     r1, [r2, #EMIF_PMCR_SHDW_VAL_OFFSET]
+
+	ldr	r1, [r0, #EMIF_SDRAM_OUTPUT_IMPEDANCE_CALIBRATION_CONFIG]
+	str     r1, [r2, #EMIF_ZQCFG_VAL_OFFSET]
+
+	ldr	r1, [r0, #EMIF_DDR_PHY_CTRL_1]
+	str     r1, [r2, #EMIF_DDR_PHY_CTLR_1_OFFSET]
+
+	ldr	r1, [r0, #EMIF_COS_CONFIG]
+	str     r1, [r2, #EMIF_COS_CONFIG_OFFSET]
+
+	ldr	r1, [r0, #EMIF_PRIORITY_TO_CLASS_OF_SERVICE_MAPPING]
+	str     r1, [r2, #EMIF_PRIORITY_TO_COS_MAPPING_OFFSET]
+
+	ldr	r1, [r0, #EMIF_CONNECTION_ID_TO_CLASS_OF_SERVICE_1_MAPPING]
+	str     r1, [r2, #EMIF_CONNECT_ID_SERV_1_MAP_OFFSET]
+
+	ldr	r1, [r0, #EMIF_CONNECTION_ID_TO_CLASS_OF_SERVICE_2_MAPPING]
+	str     r1, [r2, #EMIF_CONNECT_ID_SERV_2_MAP_OFFSET]
+
+	ldr	r1, [r0, #EMIF_OCP_CONFIG]
+	str     r1, [r2, #EMIF_OCP_CONFIG_VAL_OFFSET]
+
+	ldr	r5, [r4, #EMIF_PM_CONFIG_OFFSET]
+	cmp	r5, #EMIF_SRAM_AM43_REG_LAYOUT
+	bne	emif_skip_save_extra_regs
+
+	ldr	r1, [r0, #EMIF_READ_WRITE_LEVELING_RAMP_CONTROL]
+	str     r1, [r2, #EMIF_RD_WR_LEVEL_RAMP_CTRL_OFFSET]
+
+	ldr	r1, [r0, #EMIF_READ_WRITE_EXECUTION_THRESHOLD]
+	str     r1, [r2, #EMIF_RD_WR_EXEC_THRESH_OFFSET]
+
+	ldr	r1, [r0, #EMIF_LPDDR2_NVM_TIMING]
+	str     r1, [r2, #EMIF_LPDDR2_NVM_TIM_OFFSET]
+
+	ldr	r1, [r0, #EMIF_LPDDR2_NVM_TIMING_SHDW]
+	str     r1, [r2, #EMIF_LPDDR2_NVM_TIM_SHDW_OFFSET]
+
+	ldr	r1, [r0, #EMIF_DLL_CALIB_CTRL]
+	str     r1, [r2, #EMIF_DLL_CALIB_CTRL_VAL_OFFSET]
+
+	ldr	r1, [r0, #EMIF_DLL_CALIB_CTRL_SHDW]
+	str     r1, [r2, #EMIF_DLL_CALIB_CTRL_VAL_SHDW_OFFSET]
+
+	/* Loop and save entire block of emif phy regs */
+	mov	r5, #0x0
+	add	r4, r2, #EMIF_EXT_PHY_CTRL_VALS_OFFSET
+	add	r3, r0, #EMIF_EXT_PHY_CTRL_1
+ddr_phy_ctrl_save:
+	ldr	r1, [r3, r5]
+	str	r1, [r4, r5]
+	add	r5, r5, #0x4
+	cmp	r5, #AM43XX_EMIF_PHY_CTRL_REG_COUNT
+	bne	ddr_phy_ctrl_save
+
+emif_skip_save_extra_regs:
+	ldmfd	sp!, {r4 - r11, pc}	@ restore regs and return
+ENDPROC(ti_emif_save_context)
+
+/*
+ * void ti_emif_restore_context(void)
+ *
+ * Used during resume to restore the context of all required EMIF registers
+ * from local memory after the EMIF has lost context during a sleep transition.
+ * Operates on the PHYSICAL address of the EMIF.
+ */
+ENTRY(ti_emif_restore_context)
+	adr	r4, ti_emif_pm_sram_data
+	ldr	r0, [r4, #EMIF_PM_BASE_ADDR_PHYS_OFFSET]
+	ldr	r2, [r4, #EMIF_PM_REGS_PHYS_OFFSET]
+
+	/* Config EMIF Timings */
+	ldr     r1, [r2, #EMIF_DDR_PHY_CTLR_1_OFFSET]
+	str	r1, [r0, #EMIF_DDR_PHY_CTRL_1]
+	str	r1, [r0, #EMIF_DDR_PHY_CTRL_1_SHDW]
+
+	ldr     r1, [r2, #EMIF_TIMING1_VAL_OFFSET]
+	str	r1, [r0, #EMIF_SDRAM_TIMING_1]
+	str	r1, [r0, #EMIF_SDRAM_TIMING_1_SHDW]
+
+	ldr     r1, [r2, #EMIF_TIMING2_VAL_OFFSET]
+	str	r1, [r0, #EMIF_SDRAM_TIMING_2]
+	str	r1, [r0, #EMIF_SDRAM_TIMING_2_SHDW]
+
+	ldr     r1, [r2, #EMIF_TIMING3_VAL_OFFSET]
+	str	r1, [r0, #EMIF_SDRAM_TIMING_3]
+	str	r1, [r0, #EMIF_SDRAM_TIMING_3_SHDW]
+
+	ldr     r1, [r2, #EMIF_REF_CTRL_VAL_OFFSET]
+	str	r1, [r0, #EMIF_SDRAM_REFRESH_CONTROL]
+	str	r1, [r0, #EMIF_SDRAM_REFRESH_CTRL_SHDW]
+
+	ldr     r1, [r2, #EMIF_PMCR_VAL_OFFSET]
+	str	r1, [r0, #EMIF_POWER_MANAGEMENT_CONTROL]
+
+	ldr     r1, [r2, #EMIF_PMCR_SHDW_VAL_OFFSET]
+	str	r1, [r0, #EMIF_POWER_MANAGEMENT_CTRL_SHDW]
+
+	ldr     r1, [r2, #EMIF_COS_CONFIG_OFFSET]
+	str	r1, [r0, #EMIF_COS_CONFIG]
+
+	ldr     r1, [r2, #EMIF_PRIORITY_TO_COS_MAPPING_OFFSET]
+	str	r1, [r0, #EMIF_PRIORITY_TO_CLASS_OF_SERVICE_MAPPING]
+
+	ldr	r1, [r2, #EMIF_CONNECT_ID_SERV_1_MAP_OFFSET]
+	str	r1, [r0, #EMIF_CONNECTION_ID_TO_CLASS_OF_SERVICE_1_MAPPING]
+
+	ldr     r1, [r2, #EMIF_CONNECT_ID_SERV_2_MAP_OFFSET]
+	str	r1, [r0, #EMIF_CONNECTION_ID_TO_CLASS_OF_SERVICE_2_MAPPING]
+
+	ldr     r1, [r2, #EMIF_OCP_CONFIG_VAL_OFFSET]
+	str	r1, [r0, #EMIF_OCP_CONFIG]
+
+	ldr	r5, [r4, #EMIF_PM_CONFIG_OFFSET]
+	cmp	r5, #EMIF_SRAM_AM43_REG_LAYOUT
+	bne	emif_skip_restore_extra_regs
+
+	ldr     r1, [r2, #EMIF_RD_WR_LEVEL_RAMP_CTRL_OFFSET]
+	str	r1, [r0, #EMIF_READ_WRITE_LEVELING_RAMP_CONTROL]
+
+	ldr     r1, [r2, #EMIF_RD_WR_EXEC_THRESH_OFFSET]
+	str	r1, [r0, #EMIF_READ_WRITE_EXECUTION_THRESHOLD]
+
+	ldr     r1, [r2, #EMIF_LPDDR2_NVM_TIM_OFFSET]
+	str	r1, [r0, #EMIF_LPDDR2_NVM_TIMING]
+
+	ldr     r1, [r2, #EMIF_LPDDR2_NVM_TIM_SHDW_OFFSET]
+	str	r1, [r0, #EMIF_LPDDR2_NVM_TIMING_SHDW]
+
+	ldr     r1, [r2, #EMIF_DLL_CALIB_CTRL_VAL_OFFSET]
+	str	r1, [r0, #EMIF_DLL_CALIB_CTRL]
+
+	ldr     r1, [r2, #EMIF_DLL_CALIB_CTRL_VAL_SHDW_OFFSET]
+	str	r1, [r0, #EMIF_DLL_CALIB_CTRL_SHDW]
+
+	ldr     r1, [r2, #EMIF_ZQCFG_VAL_OFFSET]
+	str	r1, [r0, #EMIF_SDRAM_OUTPUT_IMPEDANCE_CALIBRATION_CONFIG]
+
+	/* Loop and restore entire block of emif phy regs */
+	mov	r5, #0x0
+	/* Load ti_emif_regs_amx3 + EMIF_EXT_PHY_CTRL_VALS_OFFSET for address
+	 * to phy register save space
+	 */
+	add	r3, r2, #EMIF_EXT_PHY_CTRL_VALS_OFFSET
+	add	r4, r0, #EMIF_EXT_PHY_CTRL_1
+ddr_phy_ctrl_restore:
+	ldr	r1, [r3, r5]
+	str	r1, [r4, r5]
+	add	r5, r5, #0x4
+	cmp	r5, #AM43XX_EMIF_PHY_CTRL_REG_COUNT
+	bne	ddr_phy_ctrl_restore
+
+emif_skip_restore_extra_regs:
+	/*
+	 * Output impedence calib needed only for DDR3
+	 * but since the initial state of this will be
+	 * disabled for DDR2 no harm in restoring the
+	 * old configuration
+	 */
+	ldr     r1, [r2, #EMIF_ZQCFG_VAL_OFFSET]
+	str	r1, [r0, #EMIF_SDRAM_OUTPUT_IMPEDANCE_CALIBRATION_CONFIG]
+
+	/* Write to sdcfg last for DDR2 only */
+	ldr	r1, [r2, #EMIF_SDCFG_VAL_OFFSET]
+	and	r2, r1, #SDRAM_TYPE_MASK
+	cmp	r2, #EMIF_SDCFG_TYPE_DDR2
+	streq	r1, [r0, #EMIF_SDRAM_CONFIG]
+
+	mov	pc, lr
+ENDPROC(ti_emif_restore_context)
+
+/*
+ * void ti_emif_enter_sr(void)
+ *
+ * Programs the EMIF to tell the SDRAM to enter into self-refresh
+ * mode during a sleep transition. Operates on the VIRTUAL address
+ * of the EMIF.
+ */
+ENTRY(ti_emif_enter_sr)
+	stmfd   sp!, {r4 - r11, lr}     @ save registers on stack
+
+	adr	r4, ti_emif_pm_sram_data
+	ldr	r0, [r4, #EMIF_PM_BASE_ADDR_VIRT_OFFSET]
+	ldr	r2, [r4, #EMIF_PM_REGS_VIRT_OFFSET]
+
+	ldr	r1, [r0, #EMIF_POWER_MANAGEMENT_CONTROL]
+	bic	r1, r1, #EMIF_POWER_MGMT_SELF_REFRESH_MODE_MASK
+	orr	r1, r1, #EMIF_POWER_MGMT_SELF_REFRESH_MODE
+	str	r1, [r0, #EMIF_POWER_MANAGEMENT_CONTROL]
+
+	ldmfd	sp!, {r4 - r11, pc}	@ restore regs and return
+ENDPROC(ti_emif_enter_sr)
+
+/*
+ * void ti_emif_exit_sr(void)
+ *
+ * Programs the EMIF to tell the SDRAM to exit self-refresh mode
+ * after a sleep transition. Operates on the PHYSICAL address of
+ * the EMIF.
+ */
+ENTRY(ti_emif_exit_sr)
+	adr	r4, ti_emif_pm_sram_data
+	ldr	r0, [r4, #EMIF_PM_BASE_ADDR_PHYS_OFFSET]
+	ldr	r2, [r4, #EMIF_PM_REGS_PHYS_OFFSET]
+
+	/*
+	 * Toggle EMIF to exit refresh mode:
+	 * if EMIF lost context, PWR_MGT_CTRL is currently 0, writing disable
+	 *   (0x0), wont do diddly squat! so do a toggle from SR(0x2) to disable
+	 *   (0x0) here.
+	 * *If* EMIF did not lose context, nothing broken as we write the same
+	 *   value(0x2) to reg before we write a disable (0x0).
+	 */
+	ldr	r1, [r2, #EMIF_PMCR_VAL_OFFSET]
+	bic	r1, r1, #EMIF_POWER_MGMT_SELF_REFRESH_MODE_MASK
+	orr	r1, r1, #EMIF_POWER_MGMT_SELF_REFRESH_MODE
+	str	r1, [r0, #EMIF_POWER_MANAGEMENT_CONTROL]
+	bic	r1, r1, #EMIF_POWER_MGMT_SELF_REFRESH_MODE_MASK
+	str	r1, [r0, #EMIF_POWER_MANAGEMENT_CONTROL]
+
+        /* Wait for EMIF to become ready */
+1:	ldr     r1, [r0, #EMIF_STATUS]
+	tst     r1, #EMIF_STATUS_READY
+	beq     1b
+
+	mov	pc, lr
+ENDPROC(ti_emif_exit_sr)
+
+/*
+ * void ti_emif_abort_sr(void)
+ *
+ * Disables self-refresh after a failed transition to a low-power
+ * state so the kernel can jump back to DDR and follow abort path.
+ * Operates on the VIRTUAL address of the EMIF.
+ */
+ENTRY(ti_emif_abort_sr)
+	stmfd   sp!, {r4 - r11, lr}     @ save registers on stack
+
+	adr	r4, ti_emif_pm_sram_data
+	ldr	r0, [r4, #EMIF_PM_BASE_ADDR_VIRT_OFFSET]
+	ldr	r2, [r4, #EMIF_PM_REGS_VIRT_OFFSET]
+
+	ldr	r1, [r2, #EMIF_PMCR_VAL_OFFSET]
+	bic	r1, r1, #EMIF_POWER_MGMT_SELF_REFRESH_MODE_MASK
+	str	r1, [r0, #EMIF_POWER_MANAGEMENT_CONTROL]
+
+	/* Wait for EMIF to become ready */
+1:	ldr     r1, [r0, #EMIF_STATUS]
+	tst     r1, #EMIF_STATUS_READY
+	beq     1b
+
+	ldmfd	sp!, {r4 - r11, pc}	@ restore regs and return
+ENDPROC(ti_emif_abort_sr)
+
+	.align 3
+ENTRY(ti_emif_pm_sram_data)
+	.space EMIF_PM_DATA_SIZE
+ENTRY(ti_emif_sram_sz)
+        .word   . - ti_emif_save_context