// SPDX-License-Identifier: GPL-2.0-only
/*
 * TI AM33XX SRAM EMIF Driver
 *
 * Copyright (C) 2016-2017 Texas Instruments Inc.
 *      Dave Gerlach
 */

#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_functions.run_hw_leveling =
                sram_resume_address(emif_data,
                                    (unsigned long)ti_emif_run_hw_leveling);

        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);

#ifdef CONFIG_PM_SLEEP
static int ti_emif_resume(struct device *dev)
{
        unsigned long tmp =
                        __raw_readl((void __iomem *)emif_instance->ti_emif_sram_virt);

        /*
         * Check to see if what we are copying is already present in the
         * first byte at the destination, only copy if it is not which
         * indicates we have lost context and sram no longer contains
         * the PM code
         */
        if (tmp != ti_emif_sram)
                ti_emif_push_sram(dev, emif_instance);

        return 0;
}

static int ti_emif_suspend(struct device *dev)
{
        /*
         * The contents will be present in DDR hence no need to
         * explicitly save
         */
        return 0;
}
#endif /* CONFIG_PM_SLEEP */

static int ti_emif_probe(struct platform_device *pdev)
{
        int ret;
        struct resource *res;
        struct device *dev = &pdev->dev;
        struct ti_emif_data *emif_data;

        emif_data = devm_kzalloc(dev, sizeof(*emif_data), GFP_KERNEL);
        if (!emif_data)
                return -ENOMEM;

        emif_data->pm_data.ti_emif_sram_config = (unsigned long) device_get_match_data(&pdev->dev);

        emif_data->pm_data.ti_emif_base_addr_virt = devm_platform_get_and_ioremap_resource(pdev,
                                                                                           0,
                                                                                           &res);
        if (IS_ERR(emif_data->pm_data.ti_emif_base_addr_virt)) {
                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 void ti_emif_remove(struct platform_device *pdev)
{
        struct ti_emif_data *emif_data = emif_instance;

        emif_instance = NULL;

        ti_emif_free_sram(emif_data);
}

static const struct dev_pm_ops ti_emif_pm_ops = {
        SET_SYSTEM_SLEEP_PM_OPS(ti_emif_suspend, ti_emif_resume)
};

static struct platform_driver ti_emif_driver = {
        .probe = ti_emif_probe,
        .remove = ti_emif_remove,
        .driver = {
                .name = KBUILD_MODNAME,
                .of_match_table = ti_emif_of_match,
                .pm = &ti_emif_pm_ops,
        },
};
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");