root/drivers/soc/sunxi/sunxi_sram.c
/*
 * Allwinner SoCs SRAM Controller Driver
 *
 * Copyright (C) 2015 Maxime Ripard
 *
 * Author: Maxime Ripard <maxime.ripard@free-electrons.com>
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2.  This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/debugfs.h>
#include <linux/io.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>

#include <linux/soc/sunxi/sunxi_sram.h>

struct sunxi_sram_func {
        char    *func;
        u8      val;
        u32     reg_val;
};

struct sunxi_sram_data {
        char                    *name;
        u8                      reg;
        u8                      offset;
        u8                      width;
        struct sunxi_sram_func  *func;
};

struct sunxi_sram_desc {
        struct sunxi_sram_data  data;
        bool                    claimed;
};

#define SUNXI_SRAM_MAP(_reg_val, _val, _func)                   \
        {                                                       \
                .func = _func,                                  \
                .val = _val,                                    \
                .reg_val = _reg_val,                            \
        }

#define SUNXI_SRAM_DATA(_name, _reg, _off, _width, ...)         \
        {                                                       \
                .name = _name,                                  \
                .reg = _reg,                                    \
                .offset = _off,                                 \
                .width = _width,                                \
                .func = (struct sunxi_sram_func[]){             \
                        __VA_ARGS__, { } },                     \
        }

static struct sunxi_sram_desc sun4i_a10_sram_a3_a4 = {
        .data   = SUNXI_SRAM_DATA("A3-A4", 0x4, 0x4, 2,
                                  SUNXI_SRAM_MAP(0, 0, "cpu"),
                                  SUNXI_SRAM_MAP(1, 1, "emac")),
};

static struct sunxi_sram_desc sun4i_a10_sram_c1 = {
        .data   = SUNXI_SRAM_DATA("C1", 0x0, 0x0, 31,
                                  SUNXI_SRAM_MAP(0, 0, "cpu"),
                                  SUNXI_SRAM_MAP(0x7fffffff, 1, "ve")),
};

static struct sunxi_sram_desc sun4i_a10_sram_d = {
        .data   = SUNXI_SRAM_DATA("D", 0x4, 0x0, 1,
                                  SUNXI_SRAM_MAP(0, 0, "cpu"),
                                  SUNXI_SRAM_MAP(1, 1, "usb-otg")),
};

static struct sunxi_sram_desc sun50i_a64_sram_c = {
        .data   = SUNXI_SRAM_DATA("C", 0x4, 24, 1,
                                  SUNXI_SRAM_MAP(1, 0, "cpu"),
                                  SUNXI_SRAM_MAP(0, 1, "de2")),
};

static const struct of_device_id sunxi_sram_dt_ids[] = {
        {
                .compatible     = "allwinner,sun4i-a10-sram-a3-a4",
                .data           = &sun4i_a10_sram_a3_a4.data,
        },
        {
                .compatible     = "allwinner,sun4i-a10-sram-c1",
                .data           = &sun4i_a10_sram_c1.data,
        },
        {
                .compatible     = "allwinner,sun4i-a10-sram-d",
                .data           = &sun4i_a10_sram_d.data,
        },
        {
                .compatible     = "allwinner,sun50i-a64-sram-c",
                .data           = &sun50i_a64_sram_c.data,
        },
        {}
};

static struct device *sram_dev;
static DEFINE_SPINLOCK(sram_lock);
static void __iomem *base;

static int sunxi_sram_show(struct seq_file *s, void *data)
{
        struct device_node *sram_node, *section_node;
        const struct sunxi_sram_data *sram_data;
        const struct of_device_id *match;
        struct sunxi_sram_func *func;
        const __be32 *sram_addr_p, *section_addr_p;
        u32 val;

        seq_puts(s, "Allwinner sunXi SRAM\n");
        seq_puts(s, "--------------------\n\n");

        for_each_child_of_node(sram_dev->of_node, sram_node) {
                if (!of_device_is_compatible(sram_node, "mmio-sram"))
                        continue;

                sram_addr_p = of_get_address(sram_node, 0, NULL, NULL);

                seq_printf(s, "sram@%08x\n",
                           be32_to_cpu(*sram_addr_p));

                for_each_child_of_node(sram_node, section_node) {
                        match = of_match_node(sunxi_sram_dt_ids, section_node);
                        if (!match)
                                continue;
                        sram_data = match->data;

                        section_addr_p = of_get_address(section_node, 0,
                                                        NULL, NULL);

                        seq_printf(s, "\tsection@%04x\t(%s)\n",
                                   be32_to_cpu(*section_addr_p),
                                   sram_data->name);

                        val = readl(base + sram_data->reg);
                        val >>= sram_data->offset;
                        val &= GENMASK(sram_data->width - 1, 0);

                        for (func = sram_data->func; func->func; func++) {
                                seq_printf(s, "\t\t%s%c\n", func->func,
                                           func->reg_val == val ?
                                           '*' : ' ');
                        }
                }

                seq_puts(s, "\n");
        }

        return 0;
}

DEFINE_SHOW_ATTRIBUTE(sunxi_sram);

static inline struct sunxi_sram_desc *to_sram_desc(const struct sunxi_sram_data *data)
{
        return container_of(data, struct sunxi_sram_desc, data);
}

static const struct sunxi_sram_data *sunxi_sram_of_parse(struct device_node *node,
                                                         unsigned int *reg_value)
{
        const struct of_device_id *match;
        const struct sunxi_sram_data *data;
        struct sunxi_sram_func *func;
        struct of_phandle_args args;
        u8 val;
        int ret;

        ret = of_parse_phandle_with_fixed_args(node, "allwinner,sram", 1, 0,
                                               &args);
        if (ret)
                return ERR_PTR(ret);

        if (!of_device_is_available(args.np)) {
                ret = -EBUSY;
                goto err;
        }

        val = args.args[0];

        match = of_match_node(sunxi_sram_dt_ids, args.np);
        if (!match) {
                ret = -EINVAL;
                goto err;
        }

        data = match->data;
        if (!data) {
                ret = -EINVAL;
                goto err;
        }

        for (func = data->func; func->func; func++) {
                if (val == func->val) {
                        if (reg_value)
                                *reg_value = func->reg_val;

                        break;
                }
        }

        if (!func->func) {
                ret = -EINVAL;
                goto err;
        }

        of_node_put(args.np);
        return match->data;

err:
        of_node_put(args.np);
        return ERR_PTR(ret);
}

int sunxi_sram_claim(struct device *dev)
{
        const struct sunxi_sram_data *sram_data;
        struct sunxi_sram_desc *sram_desc;
        unsigned int device;
        u32 val, mask;

        if (IS_ERR(base))
                return PTR_ERR(base);

        if (!base)
                return -EPROBE_DEFER;

        if (!dev || !dev->of_node)
                return -EINVAL;

        sram_data = sunxi_sram_of_parse(dev->of_node, &device);
        if (IS_ERR(sram_data))
                return PTR_ERR(sram_data);

        sram_desc = to_sram_desc(sram_data);

        spin_lock(&sram_lock);

        if (sram_desc->claimed) {
                spin_unlock(&sram_lock);
                return -EBUSY;
        }

        mask = GENMASK(sram_data->offset + sram_data->width - 1,
                       sram_data->offset);
        val = readl(base + sram_data->reg);
        val &= ~mask;
        writel(val | ((device << sram_data->offset) & mask),
               base + sram_data->reg);

        sram_desc->claimed = true;
        spin_unlock(&sram_lock);

        return 0;
}
EXPORT_SYMBOL(sunxi_sram_claim);

void sunxi_sram_release(struct device *dev)
{
        const struct sunxi_sram_data *sram_data;
        struct sunxi_sram_desc *sram_desc;

        if (!dev || !dev->of_node)
                return;

        sram_data = sunxi_sram_of_parse(dev->of_node, NULL);
        if (IS_ERR(sram_data))
                return;

        sram_desc = to_sram_desc(sram_data);

        spin_lock(&sram_lock);
        sram_desc->claimed = false;
        spin_unlock(&sram_lock);
}
EXPORT_SYMBOL(sunxi_sram_release);

struct sunxi_sramc_variant {
        int num_emac_clocks;
        bool has_ldo_ctrl;
        bool has_ths_offset;
};

static const struct sunxi_sramc_variant sun4i_a10_sramc_variant = {
        /* Nothing special */
};

static const struct sunxi_sramc_variant sun8i_h3_sramc_variant = {
        .num_emac_clocks = 1,
};

static const struct sunxi_sramc_variant sun20i_d1_sramc_variant = {
        .num_emac_clocks = 1,
        .has_ldo_ctrl = true,
};

static const struct sunxi_sramc_variant sun50i_a64_sramc_variant = {
        .num_emac_clocks = 1,
};

static const struct sunxi_sramc_variant sun50i_h616_sramc_variant = {
        .num_emac_clocks = 2,
        .has_ths_offset = true,
};

static const struct sunxi_sramc_variant sun55i_a523_sramc_variant = {
        .num_emac_clocks = 2,
};

#define SUNXI_SRAM_THS_OFFSET_REG       0x0
#define SUNXI_SRAM_EMAC_CLOCK_REG       0x30
#define SUNXI_SYS_LDO_CTRL_REG          0x150

static bool sunxi_sram_regmap_accessible_reg(struct device *dev,
                                             unsigned int reg)
{
        const struct sunxi_sramc_variant *variant = dev_get_drvdata(dev);

        if (reg == SUNXI_SRAM_THS_OFFSET_REG && variant->has_ths_offset)
                return true;
        if (reg >= SUNXI_SRAM_EMAC_CLOCK_REG &&
            reg <  SUNXI_SRAM_EMAC_CLOCK_REG + variant->num_emac_clocks * 4)
                return true;
        if (reg == SUNXI_SYS_LDO_CTRL_REG && variant->has_ldo_ctrl)
                return true;

        return false;
}

static void sunxi_sram_lock(void *_lock)
{
        spinlock_t *lock = _lock;

        spin_lock(lock);
}

static void sunxi_sram_unlock(void *_lock)
{
        spinlock_t *lock = _lock;

        spin_unlock(lock);
}

static const struct regmap_config sunxi_sram_regmap_config = {
        .reg_bits       = 32,
        .val_bits       = 32,
        .reg_stride     = 4,
        /* last defined register */
        .max_register   = SUNXI_SYS_LDO_CTRL_REG,
        /* other devices have no business accessing other registers */
        .readable_reg   = sunxi_sram_regmap_accessible_reg,
        .writeable_reg  = sunxi_sram_regmap_accessible_reg,
        .lock           = sunxi_sram_lock,
        .unlock         = sunxi_sram_unlock,
        .lock_arg       = &sram_lock,
};

static int __init sunxi_sram_probe(struct platform_device *pdev)
{
        const struct sunxi_sramc_variant *variant;
        struct device *dev = &pdev->dev;
        struct regmap *regmap;
        int ret;

        sram_dev = &pdev->dev;

        variant = of_device_get_match_data(&pdev->dev);
        if (!variant)
                return -EINVAL;

        dev_set_drvdata(dev, (struct sunxi_sramc_variant *)variant);

        base = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(base))
                return PTR_ERR(base);

        if (variant->num_emac_clocks || variant->has_ldo_ctrl) {
                regmap = devm_regmap_init_mmio(dev, base, &sunxi_sram_regmap_config);
                if (IS_ERR(regmap))
                        return PTR_ERR(regmap);

                ret = of_syscon_register_regmap(dev->of_node, regmap);
                if (ret)
                        return ret;
        }

        of_platform_populate(dev->of_node, NULL, NULL, dev);

        debugfs_create_file("sram", 0444, NULL, NULL, &sunxi_sram_fops);

        return 0;
}

static const struct of_device_id sunxi_sram_dt_match[] = {
        {
                .compatible = "allwinner,sun4i-a10-sram-controller",
                .data = &sun4i_a10_sramc_variant,
        },
        {
                .compatible = "allwinner,sun4i-a10-system-control",
                .data = &sun4i_a10_sramc_variant,
        },
        {
                .compatible = "allwinner,sun5i-a13-system-control",
                .data = &sun4i_a10_sramc_variant,
        },
        {
                .compatible = "allwinner,sun8i-a23-system-control",
                .data = &sun4i_a10_sramc_variant,
        },
        {
                .compatible = "allwinner,sun8i-h3-system-control",
                .data = &sun8i_h3_sramc_variant,
        },
        {
                .compatible = "allwinner,sun20i-d1-system-control",
                .data = &sun20i_d1_sramc_variant,
        },
        {
                .compatible = "allwinner,sun50i-a64-sram-controller",
                .data = &sun50i_a64_sramc_variant,
        },
        {
                .compatible = "allwinner,sun50i-a64-system-control",
                .data = &sun50i_a64_sramc_variant,
        },
        {
                .compatible = "allwinner,sun50i-h5-system-control",
                .data = &sun50i_a64_sramc_variant,
        },
        {
                .compatible = "allwinner,sun50i-h616-system-control",
                .data = &sun50i_h616_sramc_variant,
        },
        {
                .compatible = "allwinner,sun55i-a523-system-control",
                .data = &sun55i_a523_sramc_variant,
        },
        { },
};
MODULE_DEVICE_TABLE(of, sunxi_sram_dt_match);

static struct platform_driver sunxi_sram_driver = {
        .driver = {
                .name           = "sunxi-sram",
                .of_match_table = sunxi_sram_dt_match,
        },
};
builtin_platform_driver_probe(sunxi_sram_driver, sunxi_sram_probe);

MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
MODULE_DESCRIPTION("Allwinner sunXi SRAM Controller Driver");