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![Dave Gerlach](/assets/img/avatar_default.png)
After an RTC+DDR cycle we lose sram context so emif pm functions present in sram are lost. We can check if the first byte of the original code in DDR contains the same first byte as the code in sram, and if they do not match we know we have lost context and must recopy the functions to the previous address to maintain PM functionality. Signed-off-by: Dave Gerlach <d-gerlach@ti.com> Signed-off-by: Keerthy <j-keerthy@ti.com> Signed-off-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
356 lines
9.5 KiB
C
356 lines
9.5 KiB
C
/*
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* TI AM33XX SRAM EMIF Driver
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*
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* Copyright (C) 2016-2017 Texas Instruments Inc.
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* Dave Gerlach
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* version 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/err.h>
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#include <linux/genalloc.h>
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#include <linux/io.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/of_platform.h>
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#include <linux/platform_device.h>
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#include <linux/sram.h>
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#include <linux/ti-emif-sram.h>
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#include "emif.h"
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#define TI_EMIF_SRAM_SYMBOL_OFFSET(sym) ((unsigned long)(sym) - \
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(unsigned long)&ti_emif_sram)
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#define EMIF_POWER_MGMT_WAIT_SELF_REFRESH_8192_CYCLES 0x00a0
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struct ti_emif_data {
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phys_addr_t ti_emif_sram_phys;
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phys_addr_t ti_emif_sram_data_phys;
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unsigned long ti_emif_sram_virt;
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unsigned long ti_emif_sram_data_virt;
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struct gen_pool *sram_pool_code;
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struct gen_pool *sram_pool_data;
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struct ti_emif_pm_data pm_data;
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struct ti_emif_pm_functions pm_functions;
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};
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static struct ti_emif_data *emif_instance;
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static u32 sram_suspend_address(struct ti_emif_data *emif_data,
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unsigned long addr)
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{
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return (emif_data->ti_emif_sram_virt +
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TI_EMIF_SRAM_SYMBOL_OFFSET(addr));
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}
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static phys_addr_t sram_resume_address(struct ti_emif_data *emif_data,
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unsigned long addr)
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{
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return ((unsigned long)emif_data->ti_emif_sram_phys +
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TI_EMIF_SRAM_SYMBOL_OFFSET(addr));
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}
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static void ti_emif_free_sram(struct ti_emif_data *emif_data)
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{
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gen_pool_free(emif_data->sram_pool_code, emif_data->ti_emif_sram_virt,
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ti_emif_sram_sz);
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gen_pool_free(emif_data->sram_pool_data,
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emif_data->ti_emif_sram_data_virt,
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sizeof(struct emif_regs_amx3));
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}
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static int ti_emif_alloc_sram(struct device *dev,
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struct ti_emif_data *emif_data)
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{
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struct device_node *np = dev->of_node;
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int ret;
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emif_data->sram_pool_code = of_gen_pool_get(np, "sram", 0);
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if (!emif_data->sram_pool_code) {
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dev_err(dev, "Unable to get sram pool for ocmcram code\n");
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return -ENODEV;
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}
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emif_data->ti_emif_sram_virt =
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gen_pool_alloc(emif_data->sram_pool_code,
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ti_emif_sram_sz);
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if (!emif_data->ti_emif_sram_virt) {
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dev_err(dev, "Unable to allocate code memory from ocmcram\n");
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return -ENOMEM;
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}
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/* Save physical address to calculate resume offset during pm init */
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emif_data->ti_emif_sram_phys =
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gen_pool_virt_to_phys(emif_data->sram_pool_code,
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emif_data->ti_emif_sram_virt);
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/* Get sram pool for data section and allocate space */
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emif_data->sram_pool_data = of_gen_pool_get(np, "sram", 1);
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if (!emif_data->sram_pool_data) {
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dev_err(dev, "Unable to get sram pool for ocmcram data\n");
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ret = -ENODEV;
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goto err_free_sram_code;
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}
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emif_data->ti_emif_sram_data_virt =
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gen_pool_alloc(emif_data->sram_pool_data,
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sizeof(struct emif_regs_amx3));
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if (!emif_data->ti_emif_sram_data_virt) {
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dev_err(dev, "Unable to allocate data memory from ocmcram\n");
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ret = -ENOMEM;
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goto err_free_sram_code;
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}
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/* Save physical address to calculate resume offset during pm init */
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emif_data->ti_emif_sram_data_phys =
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gen_pool_virt_to_phys(emif_data->sram_pool_data,
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emif_data->ti_emif_sram_data_virt);
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/*
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* These functions are called during suspend path while MMU is
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* still on so add virtual base to offset for absolute address
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*/
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emif_data->pm_functions.save_context =
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sram_suspend_address(emif_data,
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(unsigned long)ti_emif_save_context);
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emif_data->pm_functions.enter_sr =
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sram_suspend_address(emif_data,
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(unsigned long)ti_emif_enter_sr);
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emif_data->pm_functions.abort_sr =
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sram_suspend_address(emif_data,
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(unsigned long)ti_emif_abort_sr);
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/*
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* These are called during resume path when MMU is not enabled
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* so physical address is used instead
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*/
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emif_data->pm_functions.restore_context =
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sram_resume_address(emif_data,
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(unsigned long)ti_emif_restore_context);
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emif_data->pm_functions.exit_sr =
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sram_resume_address(emif_data,
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(unsigned long)ti_emif_exit_sr);
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emif_data->pm_data.regs_virt =
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(struct emif_regs_amx3 *)emif_data->ti_emif_sram_data_virt;
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emif_data->pm_data.regs_phys = emif_data->ti_emif_sram_data_phys;
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return 0;
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err_free_sram_code:
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gen_pool_free(emif_data->sram_pool_code, emif_data->ti_emif_sram_virt,
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ti_emif_sram_sz);
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return ret;
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}
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static int ti_emif_push_sram(struct device *dev, struct ti_emif_data *emif_data)
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{
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void *copy_addr;
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u32 data_addr;
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copy_addr = sram_exec_copy(emif_data->sram_pool_code,
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(void *)emif_data->ti_emif_sram_virt,
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&ti_emif_sram, ti_emif_sram_sz);
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if (!copy_addr) {
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dev_err(dev, "Cannot copy emif code to sram\n");
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return -ENODEV;
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}
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data_addr = sram_suspend_address(emif_data,
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(unsigned long)&ti_emif_pm_sram_data);
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copy_addr = sram_exec_copy(emif_data->sram_pool_code,
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(void *)data_addr,
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&emif_data->pm_data,
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sizeof(emif_data->pm_data));
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if (!copy_addr) {
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dev_err(dev, "Cannot copy emif data to code sram\n");
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return -ENODEV;
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}
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return 0;
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}
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/*
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* Due to Usage Note 3.1.2 "DDR3: JEDEC Compliance for Maximum
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* Self-Refresh Command Limit" found in AM335x Silicon Errata
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* (Document SPRZ360F Revised November 2013) we must configure
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* the self refresh delay timer to 0xA (8192 cycles) to avoid
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* generating too many refresh command from the EMIF.
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*/
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static void ti_emif_configure_sr_delay(struct ti_emif_data *emif_data)
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{
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writel(EMIF_POWER_MGMT_WAIT_SELF_REFRESH_8192_CYCLES,
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(emif_data->pm_data.ti_emif_base_addr_virt +
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EMIF_POWER_MANAGEMENT_CONTROL));
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writel(EMIF_POWER_MGMT_WAIT_SELF_REFRESH_8192_CYCLES,
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(emif_data->pm_data.ti_emif_base_addr_virt +
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EMIF_POWER_MANAGEMENT_CTRL_SHDW));
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}
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/**
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* ti_emif_copy_pm_function_table - copy mapping of pm funcs in sram
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* @sram_pool: pointer to struct gen_pool where dst resides
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* @dst: void * to address that table should be copied
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*
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* Returns 0 if success other error code if table is not available
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*/
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int ti_emif_copy_pm_function_table(struct gen_pool *sram_pool, void *dst)
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{
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void *copy_addr;
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if (!emif_instance)
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return -ENODEV;
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copy_addr = sram_exec_copy(sram_pool, dst,
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&emif_instance->pm_functions,
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sizeof(emif_instance->pm_functions));
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if (!copy_addr)
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return -ENODEV;
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return 0;
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}
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EXPORT_SYMBOL_GPL(ti_emif_copy_pm_function_table);
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/**
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* ti_emif_get_mem_type - return type for memory type in use
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*
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* Returns memory type value read from EMIF or error code if fails
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*/
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int ti_emif_get_mem_type(void)
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{
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unsigned long temp;
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if (!emif_instance)
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return -ENODEV;
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temp = readl(emif_instance->pm_data.ti_emif_base_addr_virt +
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EMIF_SDRAM_CONFIG);
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temp = (temp & SDRAM_TYPE_MASK) >> SDRAM_TYPE_SHIFT;
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return temp;
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}
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EXPORT_SYMBOL_GPL(ti_emif_get_mem_type);
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static const struct of_device_id ti_emif_of_match[] = {
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{ .compatible = "ti,emif-am3352", .data =
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(void *)EMIF_SRAM_AM33_REG_LAYOUT, },
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{ .compatible = "ti,emif-am4372", .data =
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(void *)EMIF_SRAM_AM43_REG_LAYOUT, },
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{},
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};
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MODULE_DEVICE_TABLE(of, ti_emif_of_match);
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#ifdef CONFIG_PM_SLEEP
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static int ti_emif_resume(struct device *dev)
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{
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unsigned long tmp =
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__raw_readl((void *)emif_instance->ti_emif_sram_virt);
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/*
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* Check to see if what we are copying is already present in the
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* first byte at the destination, only copy if it is not which
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* indicates we have lost context and sram no longer contains
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* the PM code
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*/
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if (tmp != ti_emif_sram)
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ti_emif_push_sram(dev, emif_instance);
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return 0;
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}
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static int ti_emif_suspend(struct device *dev)
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{
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/*
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* The contents will be present in DDR hence no need to
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* explicitly save
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*/
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return 0;
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}
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#endif /* CONFIG_PM_SLEEP */
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static int ti_emif_probe(struct platform_device *pdev)
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{
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int ret;
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struct resource *res;
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struct device *dev = &pdev->dev;
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const struct of_device_id *match;
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struct ti_emif_data *emif_data;
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emif_data = devm_kzalloc(dev, sizeof(*emif_data), GFP_KERNEL);
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if (!emif_data)
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return -ENOMEM;
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match = of_match_device(ti_emif_of_match, &pdev->dev);
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if (!match)
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return -ENODEV;
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emif_data->pm_data.ti_emif_sram_config = (unsigned long)match->data;
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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emif_data->pm_data.ti_emif_base_addr_virt = devm_ioremap_resource(dev,
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res);
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if (IS_ERR(emif_data->pm_data.ti_emif_base_addr_virt)) {
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ret = PTR_ERR(emif_data->pm_data.ti_emif_base_addr_virt);
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return ret;
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}
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emif_data->pm_data.ti_emif_base_addr_phys = res->start;
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ti_emif_configure_sr_delay(emif_data);
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ret = ti_emif_alloc_sram(dev, emif_data);
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if (ret)
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return ret;
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ret = ti_emif_push_sram(dev, emif_data);
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if (ret)
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goto fail_free_sram;
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emif_instance = emif_data;
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return 0;
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fail_free_sram:
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ti_emif_free_sram(emif_data);
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return ret;
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}
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static int ti_emif_remove(struct platform_device *pdev)
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{
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struct ti_emif_data *emif_data = emif_instance;
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emif_instance = NULL;
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ti_emif_free_sram(emif_data);
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return 0;
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}
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static const struct dev_pm_ops ti_emif_pm_ops = {
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SET_SYSTEM_SLEEP_PM_OPS(ti_emif_suspend, ti_emif_resume)
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};
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static struct platform_driver ti_emif_driver = {
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.probe = ti_emif_probe,
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.remove = ti_emif_remove,
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.driver = {
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.name = KBUILD_MODNAME,
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.of_match_table = of_match_ptr(ti_emif_of_match),
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.pm = &ti_emif_pm_ops,
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},
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};
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module_platform_driver(ti_emif_driver);
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MODULE_AUTHOR("Dave Gerlach <d-gerlach@ti.com>");
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MODULE_DESCRIPTION("Texas Instruments SRAM EMIF driver");
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MODULE_LICENSE("GPL v2");
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