diff options
Diffstat (limited to 'drivers/base/regmap/regmap-mmio.c')
| -rw-r--r-- | drivers/base/regmap/regmap-mmio.c | 224 |
1 files changed, 224 insertions, 0 deletions
diff --git a/drivers/base/regmap/regmap-mmio.c b/drivers/base/regmap/regmap-mmio.c new file mode 100644 index 000000000000..febd6de6c8ac --- /dev/null +++ b/drivers/base/regmap/regmap-mmio.c @@ -0,0 +1,224 @@ +/* + * Register map access API - MMIO support + * + * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope 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. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/err.h> +#include <linux/init.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/regmap.h> +#include <linux/slab.h> + +struct regmap_mmio_context { + void __iomem *regs; + unsigned val_bytes; +}; + +static int regmap_mmio_gather_write(void *context, + const void *reg, size_t reg_size, + const void *val, size_t val_size) +{ + struct regmap_mmio_context *ctx = context; + u32 offset; + + BUG_ON(reg_size != 4); + + offset = be32_to_cpup(reg); + + while (val_size) { + switch (ctx->val_bytes) { + case 1: + writeb(*(u8 *)val, ctx->regs + offset); + break; + case 2: + writew(be16_to_cpup(val), ctx->regs + offset); + break; + case 4: + writel(be32_to_cpup(val), ctx->regs + offset); + break; +#ifdef CONFIG_64BIT + case 8: + writeq(be64_to_cpup(val), ctx->regs + offset); + break; +#endif + default: + /* Should be caught by regmap_mmio_check_config */ + BUG(); + } + val_size -= ctx->val_bytes; + val += ctx->val_bytes; + offset += ctx->val_bytes; + } + + return 0; +} + +static int regmap_mmio_write(void *context, const void *data, size_t count) +{ + BUG_ON(count < 4); + + return regmap_mmio_gather_write(context, data, 4, data + 4, count - 4); +} + +static int regmap_mmio_read(void *context, + const void *reg, size_t reg_size, + void *val, size_t val_size) +{ + struct regmap_mmio_context *ctx = context; + u32 offset; + + BUG_ON(reg_size != 4); + + offset = be32_to_cpup(reg); + + while (val_size) { + switch (ctx->val_bytes) { + case 1: + *(u8 *)val = readb(ctx->regs + offset); + break; + case 2: + *(u16 *)val = cpu_to_be16(readw(ctx->regs + offset)); + break; + case 4: + *(u32 *)val = cpu_to_be32(readl(ctx->regs + offset)); + break; +#ifdef CONFIG_64BIT + case 8: + *(u64 *)val = cpu_to_be32(readq(ctx->regs + offset)); + break; +#endif + default: + /* Should be caught by regmap_mmio_check_config */ + BUG(); + } + val_size -= ctx->val_bytes; + val += ctx->val_bytes; + offset += ctx->val_bytes; + } + + return 0; +} + +static void regmap_mmio_free_context(void *context) +{ + kfree(context); +} + +static struct regmap_bus regmap_mmio = { + .fast_io = true, + .write = regmap_mmio_write, + .gather_write = regmap_mmio_gather_write, + .read = regmap_mmio_read, + .free_context = regmap_mmio_free_context, +}; + +struct regmap_mmio_context *regmap_mmio_gen_context(void __iomem *regs, + const struct regmap_config *config) +{ + struct regmap_mmio_context *ctx; + int min_stride; + + if (config->reg_bits != 32) + return ERR_PTR(-EINVAL); + + if (config->pad_bits) + return ERR_PTR(-EINVAL); + + switch (config->val_bits) { + case 8: + /* The core treats 0 as 1 */ + min_stride = 0; + break; + case 16: + min_stride = 2; + break; + case 32: + min_stride = 4; + break; +#ifdef CONFIG_64BIT + case 64: + min_stride = 8; + break; +#endif + break; + default: + return ERR_PTR(-EINVAL); + } + + if (config->reg_stride < min_stride) + return ERR_PTR(-EINVAL); + + ctx = kzalloc(GFP_KERNEL, sizeof(*ctx)); + if (!ctx) + return ERR_PTR(-ENOMEM); + + ctx->regs = regs; + ctx->val_bytes = config->val_bits / 8; + + return ctx; +} + +/** + * regmap_init_mmio(): Initialise register map + * + * @dev: Device that will be interacted with + * @regs: Pointer to memory-mapped IO region + * @config: Configuration for register map + * + * The return value will be an ERR_PTR() on error or a valid pointer to + * a struct regmap. + */ +struct regmap *regmap_init_mmio(struct device *dev, + void __iomem *regs, + const struct regmap_config *config) +{ + struct regmap_mmio_context *ctx; + + ctx = regmap_mmio_gen_context(regs, config); + if (IS_ERR(ctx)) + return ERR_CAST(ctx); + + return regmap_init(dev, ®map_mmio, ctx, config); +} +EXPORT_SYMBOL_GPL(regmap_init_mmio); + +/** + * devm_regmap_init_mmio(): Initialise managed register map + * + * @dev: Device that will be interacted with + * @regs: Pointer to memory-mapped IO region + * @config: Configuration for register map + * + * The return value will be an ERR_PTR() on error or a valid pointer + * to a struct regmap. The regmap will be automatically freed by the + * device management code. + */ +struct regmap *devm_regmap_init_mmio(struct device *dev, + void __iomem *regs, + const struct regmap_config *config) +{ + struct regmap_mmio_context *ctx; + + ctx = regmap_mmio_gen_context(regs, config); + if (IS_ERR(ctx)) + return ERR_CAST(ctx); + + return devm_regmap_init(dev, ®map_mmio, ctx, config); +} +EXPORT_SYMBOL_GPL(devm_regmap_init_mmio); + +MODULE_LICENSE("GPL v2"); |