Commit 45f5ff81 authored by Stephen Warren's avatar Stephen Warren Committed by Mark Brown
Browse files

regmap: add MMIO bus support 



This is a basic memory-mapped-IO bus for regmap. It has the following
features and limitations:

* Registers themselves may be 8, 16, 32, or 64-bit. 64-bit is only
  supported on 64-bit platforms.
* Register offsets are limited to precisely 32-bit.
* IO is performed using readl/writel, with no provision for using the
  __raw_readl or readl_relaxed variants.

Signed-off-by: default avatarStephen Warren <swarren@nvidia.com>
Signed-off-by: default avatarMark Brown <broonie@opensource.wolfsonmicro.com>
parent bacdbe07

drivers/base/regmap/Kconfig

+3 −0
Original line number Diff line number Diff line
@@ -14,5 +14,8 @@ config REGMAP_I2C 
config REGMAP_SPI

	tristate



config REGMAP_MMIO

	tristate



config REGMAP_IRQ

	bool

drivers/base/regmap/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -3,4 +3,5 @@ obj-$(CONFIG_REGMAP) += regcache-rbtree.o regcache-lzo.o 
obj-$(CONFIG_DEBUG_FS) += regmap-debugfs.o

obj-$(CONFIG_REGMAP_I2C) += regmap-i2c.o

obj-$(CONFIG_REGMAP_SPI) += regmap-spi.o

obj-$(CONFIG_REGMAP_MMIO) += regmap-mmio.o

obj-$(CONFIG_REGMAP_IRQ) += regmap-irq.o

drivers/base/regmap/regmap-mmio.c

0 → 100644
+217 −0
Original line number Diff line number Diff line 
/*

 * 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;



	if (reg_size != 4)

		return -EIO;

	if (val_size % ctx->val_bytes)

		return -EIO;



	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 */

			return -EIO;

		}

		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)

{

	if (count < 4)

		return -EIO;

	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;



	if (reg_size != 4)

		return -EIO;

	if (val_size % ctx->val_bytes)

		return -EIO;



	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 */

			return -EIO;

		}

		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;



	if (config->reg_bits != 32)

		return ERR_PTR(-EINVAL);



	if (config->pad_bits)

		return ERR_PTR(-EINVAL);



	switch (config->val_bits) {

	case 8:

	case 16:

	case 32:

#ifdef CONFIG_64BIT

	case 64:

#endif

		break;

	default:

		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, &regmap_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, &regmap_mmio, ctx, config);

}

EXPORT_SYMBOL_GPL(devm_regmap_init_mmio);



MODULE_LICENSE("GPL v2");

include/linux/regmap.h

+6 −0
Original line number Diff line number Diff line
@@ -137,6 +137,9 @@ struct regmap *regmap_init_i2c(struct i2c_client *i2c, 
			       const struct regmap_config *config);

struct regmap *regmap_init_spi(struct spi_device *dev,

			       const struct regmap_config *config);

struct regmap *regmap_init_mmio(struct device *dev,

				void __iomem *regs,

				const struct regmap_config *config);



struct regmap *devm_regmap_init(struct device *dev,

				const struct regmap_bus *bus,
@@ -146,6 +149,9 @@ struct regmap *devm_regmap_init_i2c(struct i2c_client *i2c, 
				    const struct regmap_config *config);

struct regmap *devm_regmap_init_spi(struct spi_device *dev,

				    const struct regmap_config *config);

struct regmap *devm_regmap_init_mmio(struct device *dev,

				     void __iomem *regs,

				     const struct regmap_config *config);



void regmap_exit(struct regmap *map);

int regmap_reinit_cache(struct regmap *map,

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