Commit c3e4bc54 authored by Beniamino Galvani's avatar Beniamino Galvani Committed by Mark Brown
Browse files

spi: meson: Add support for Amlogic Meson SPIFC 



This is a driver for the Amlogic Meson SPIFC (SPI flash controller),
which is one of the two SPI controllers available on the SoC. It
doesn't support DMA and has a 64-byte unified transmit/receive buffer.

The device is optimized for interfacing with SPI NOR memories and
allows the execution of standard operations such as read, page
program, sector erase, etc. in a simplified way, toggling a bit in a
dedicated register. The driver doesn't use those predefined commands
and relies only on custom transfers.

Signed-off-by: default avatarBeniamino Galvani <b.galvani@gmail.com>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 56da2aaf

drivers/spi/Kconfig

+7 −0
Original line number Diff line number Diff line
@@ -301,6 +301,13 @@ config SPI_FSL_ESPI 
	  From MPC8536, 85xx platform uses the controller, and all P10xx,

	  P20xx, P30xx,P40xx, P50xx uses this controller.



config SPI_MESON_SPIFC

	tristate "Amlogic Meson SPIFC controller"

	depends on ARCH_MESON || COMPILE_TEST

	help

	  This enables master mode support for the SPIFC (SPI flash

	  controller) available in Amlogic Meson SoCs.



config SPI_OC_TINY

	tristate "OpenCores tiny SPI"

	depends on GPIOLIB

drivers/spi/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -42,6 +42,7 @@ obj-$(CONFIG_SPI_FSL_SPI) += spi-fsl-spi.o 
obj-$(CONFIG_SPI_GPIO)			+= spi-gpio.o

obj-$(CONFIG_SPI_IMX)			+= spi-imx.o

obj-$(CONFIG_SPI_LM70_LLP)		+= spi-lm70llp.o

obj-$(CONFIG_SPI_MESON_SPIFC)		+= spi-meson-spifc.o

obj-$(CONFIG_SPI_MPC512x_PSC)		+= spi-mpc512x-psc.o

obj-$(CONFIG_SPI_MPC52xx_PSC)		+= spi-mpc52xx-psc.o

obj-$(CONFIG_SPI_MPC52xx)		+= spi-mpc52xx.o

drivers/spi/spi-meson-spifc.c

0 → 100644
+462 −0
Original line number Diff line number Diff line 
/*

 * Driver for Amlogic Meson SPI flash controller (SPIFC)

 *

 * Copyright (C) 2014 Beniamino Galvani <b.galvani@gmail.com>

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * version 2 as published by the Free Software Foundation.

 *

 * 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/clk.h>

#include <linux/delay.h>

#include <linux/device.h>

#include <linux/io.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/of.h>

#include <linux/platform_device.h>

#include <linux/pm_runtime.h>

#include <linux/regmap.h>

#include <linux/spi/spi.h>

#include <linux/types.h>



/* register map */

#define REG_CMD			0x00

#define REG_ADDR		0x04

#define REG_CTRL		0x08

#define REG_CTRL1		0x0c

#define REG_STATUS		0x10

#define REG_CTRL2		0x14

#define REG_CLOCK		0x18

#define REG_USER		0x1c

#define REG_USER1		0x20

#define REG_USER2		0x24

#define REG_USER3		0x28

#define REG_USER4		0x2c

#define REG_SLAVE		0x30

#define REG_SLAVE1		0x34

#define REG_SLAVE2		0x38

#define REG_SLAVE3		0x3c

#define REG_C0			0x40

#define REG_B8			0x60

#define REG_MAX			0x7c



/* register fields */

#define CMD_USER		BIT(18)

#define CTRL_ENABLE_AHB		BIT(17)

#define CLOCK_SOURCE		BIT(31)

#define CLOCK_DIV_SHIFT		12

#define CLOCK_DIV_MASK		(0x3f << CLOCK_DIV_SHIFT)

#define CLOCK_CNT_HIGH_SHIFT	6

#define CLOCK_CNT_HIGH_MASK	(0x3f << CLOCK_CNT_HIGH_SHIFT)

#define CLOCK_CNT_LOW_SHIFT	0

#define CLOCK_CNT_LOW_MASK	(0x3f << CLOCK_CNT_LOW_SHIFT)

#define USER_DIN_EN_MS		BIT(0)

#define USER_CMP_MODE		BIT(2)

#define USER_UC_DOUT_SEL	BIT(27)

#define USER_UC_DIN_SEL		BIT(28)

#define USER_UC_MASK		((BIT(5) - 1) << 27)

#define USER1_BN_UC_DOUT_SHIFT	17

#define USER1_BN_UC_DOUT_MASK	(0xff << 16)

#define USER1_BN_UC_DIN_SHIFT	8

#define USER1_BN_UC_DIN_MASK	(0xff << 8)

#define USER4_CS_ACT		BIT(30)

#define SLAVE_TRST_DONE		BIT(4)

#define SLAVE_OP_MODE		BIT(30)

#define SLAVE_SW_RST		BIT(31)



#define SPIFC_BUFFER_SIZE	64



/**

 * struct meson_spifc

 * @master:	the SPI master

 * @regmap:	regmap for device registers

 * @clk:	input clock of the built-in baud rate generator

 * @device:	the device structure

 */

struct meson_spifc {

	struct spi_master *master;

	struct regmap *regmap;

	struct clk *clk;

	struct device *dev;

};



static struct regmap_config spifc_regmap_config = {

	.reg_bits = 32,

	.val_bits = 32,

	.reg_stride = 4,

	.max_register = REG_MAX,

};



/**

 * meson_spifc_wait_ready() - wait for the current operation to terminate

 * @spifc:	the Meson SPI device

 * Return:	0 on success, a negative value on error

 */

static int meson_spifc_wait_ready(struct meson_spifc *spifc)

{

	unsigned long deadline = jiffies + msecs_to_jiffies(5);

	u32 data;



	do {

		regmap_read(spifc->regmap, REG_SLAVE, &data);

		if (data & SLAVE_TRST_DONE)

			return 0;

		cond_resched();

	} while (!time_after(jiffies, deadline));



	return -ETIMEDOUT;

}



/**

 * meson_spifc_drain_buffer() - copy data from device buffer to memory

 * @spifc:	the Meson SPI device

 * @buf:	the destination buffer

 * @len:	number of bytes to copy

 */

static void meson_spifc_drain_buffer(struct meson_spifc *spifc, u8 *buf,

				     int len)

{

	u32 data;

	int i = 0;



	while (i < len) {

		regmap_read(spifc->regmap, REG_C0 + i, &data);



		if (len - i >= 4) {

			*((u32 *)buf) = data;

			buf += 4;

		} else {

			memcpy(buf, &data, len - i);

			break;

		}

		i += 4;

	}

}



/**

 * meson_spifc_fill_buffer() - copy data from memory to device buffer

 * @spifc:	the Meson SPI device

 * @buf:	the source buffer

 * @len:	number of bytes to copy

 */

static void meson_spifc_fill_buffer(struct meson_spifc *spifc, const u8 *buf,

				    int len)

{

	u32 data;

	int i = 0;



	while (i < len) {

		if (len - i >= 4)

			data = *(u32 *)buf;

		else

			memcpy(&data, buf, len - i);



		regmap_write(spifc->regmap, REG_C0 + i, data);



		buf += 4;

		i += 4;

	}

}



/**

 * meson_spifc_setup_speed() - program the clock divider

 * @spifc:	the Meson SPI device

 * @speed:	desired speed in Hz

 */

void meson_spifc_setup_speed(struct meson_spifc *spifc, u32 speed)

{

	unsigned long parent, value;

	int n;



	parent = clk_get_rate(spifc->clk);

	n = max_t(int, parent / speed - 1, 1);



	dev_dbg(spifc->dev, "parent %lu, speed %u, n %d\n", parent,

		speed, n);



	value = (n << CLOCK_DIV_SHIFT) & CLOCK_DIV_MASK;

	value |= (n << CLOCK_CNT_LOW_SHIFT) & CLOCK_CNT_LOW_MASK;

	value |= (((n + 1) / 2 - 1) << CLOCK_CNT_HIGH_SHIFT) &

		CLOCK_CNT_HIGH_MASK;



	regmap_write(spifc->regmap, REG_CLOCK, value);

}



/**

 * meson_spifc_txrx() - transfer a chunk of data

 * @spifc:	the Meson SPI device

 * @xfer:	the current SPI transfer

 * @offset:	offset of the data to transfer

 * @len:	length of the data to transfer

 * @last_xfer:	whether this is the last transfer of the message

 * @last_chunk:	whether this is the last chunk of the transfer

 * Return:	0 on success, a negative value on error

 */

static int meson_spifc_txrx(struct meson_spifc *spifc,

			    struct spi_transfer *xfer,

			    int offset, int len, bool last_xfer,

			    bool last_chunk)

{

	bool keep_cs = true;

	int ret;



	if (xfer->tx_buf)

		meson_spifc_fill_buffer(spifc, xfer->tx_buf + offset, len);



	/* enable DOUT stage */

	regmap_update_bits(spifc->regmap, REG_USER, USER_UC_MASK,

			   USER_UC_DOUT_SEL);

	regmap_write(spifc->regmap, REG_USER1,

		     (8 * len - 1) << USER1_BN_UC_DOUT_SHIFT);



	/* enable data input during DOUT */

	regmap_update_bits(spifc->regmap, REG_USER, USER_DIN_EN_MS,

			   USER_DIN_EN_MS);



	if (last_chunk) {

		if (last_xfer)

			keep_cs = xfer->cs_change;

		else

			keep_cs = !xfer->cs_change;

	}



	regmap_update_bits(spifc->regmap, REG_USER4, USER4_CS_ACT,

			   keep_cs ? USER4_CS_ACT : 0);



	/* clear transition done bit */

	regmap_update_bits(spifc->regmap, REG_SLAVE, SLAVE_TRST_DONE, 0);

	/* start transfer */

	regmap_update_bits(spifc->regmap, REG_CMD, CMD_USER, CMD_USER);



	ret = meson_spifc_wait_ready(spifc);



	if (!ret && xfer->rx_buf)

		meson_spifc_drain_buffer(spifc, xfer->rx_buf + offset, len);



	return ret;

}



/**

 * meson_spifc_transfer_one() - perform a single transfer

 * @master:	the SPI master

 * @spi:	the SPI device

 * @xfer:	the current SPI transfer

 * Return:	0 on success, a negative value on error

 */

static int meson_spifc_transfer_one(struct spi_master *master,

				    struct spi_device *spi,

				    struct spi_transfer *xfer)

{

	struct meson_spifc *spifc = spi_master_get_devdata(master);

	int len, done = 0, ret = 0;



	meson_spifc_setup_speed(spifc, xfer->speed_hz);



	regmap_update_bits(spifc->regmap, REG_CTRL, CTRL_ENABLE_AHB, 0);



	while (done < xfer->len && !ret) {

		len = min_t(int, xfer->len - done, SPIFC_BUFFER_SIZE);

		ret = meson_spifc_txrx(spifc, xfer, done, len,

				       spi_transfer_is_last(master, xfer),

				       done + len >= xfer->len);

		done += len;

	}



	regmap_update_bits(spifc->regmap, REG_CTRL, CTRL_ENABLE_AHB,

			   CTRL_ENABLE_AHB);



	return ret;

}



/**

 * meson_spifc_hw_init() - reset and initialize the SPI controller

 * @spifc:	the Meson SPI device

 */

static void meson_spifc_hw_init(struct meson_spifc *spifc)

{

	/* reset device */

	regmap_update_bits(spifc->regmap, REG_SLAVE, SLAVE_SW_RST,

			   SLAVE_SW_RST);

	/* disable compatible mode */

	regmap_update_bits(spifc->regmap, REG_USER, USER_CMP_MODE, 0);

	/* set master mode */

	regmap_update_bits(spifc->regmap, REG_SLAVE, SLAVE_OP_MODE, 0);

}



static int meson_spifc_probe(struct platform_device *pdev)

{

	struct spi_master *master;

	struct meson_spifc *spifc;

	struct resource *res;

	void __iomem *base;

	unsigned int rate;

	int ret = 0;



	master = spi_alloc_master(&pdev->dev, sizeof(struct meson_spifc));

	if (!master)

		return -ENOMEM;



	platform_set_drvdata(pdev, master);



	spifc = spi_master_get_devdata(master);

	spifc->dev = &pdev->dev;



	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	base = devm_ioremap_resource(spifc->dev, res);

	if (IS_ERR(base)) {

		ret = PTR_ERR(base);

		goto out_err;

	}



	spifc->regmap = devm_regmap_init_mmio(spifc->dev, base,

					      &spifc_regmap_config);

	if (IS_ERR(spifc->regmap)) {

		ret = PTR_ERR(spifc->regmap);

		goto out_err;

	}



	spifc->clk = devm_clk_get(spifc->dev, NULL);

	if (IS_ERR(spifc->clk)) {

		dev_err(spifc->dev, "missing clock\n");

		ret = PTR_ERR(spifc->clk);

		goto out_err;

	}



	ret = clk_prepare_enable(spifc->clk);

	if (ret) {

		dev_err(spifc->dev, "can't prepare clock\n");

		goto out_err;

	}



	rate = clk_get_rate(spifc->clk);



	master->num_chipselect = 1;

	master->dev.of_node = pdev->dev.of_node;

	master->bits_per_word_mask = SPI_BPW_MASK(8);

	master->auto_runtime_pm = true;

	master->transfer_one = meson_spifc_transfer_one;

	master->min_speed_hz = rate >> 6;

	master->max_speed_hz = rate >> 1;



	meson_spifc_hw_init(spifc);



	pm_runtime_set_active(spifc->dev);

	pm_runtime_enable(spifc->dev);



	ret = devm_spi_register_master(spifc->dev, master);

	if (ret) {

		dev_err(spifc->dev, "failed to register spi master\n");

		goto out_clk;

	}



	return 0;

out_clk:

	clk_disable_unprepare(spifc->clk);

out_err:

	spi_master_put(master);

	return ret;

}



static int meson_spifc_remove(struct platform_device *pdev)

{

	struct spi_master *master = platform_get_drvdata(pdev);

	struct meson_spifc *spifc = spi_master_get_devdata(master);



	pm_runtime_get_sync(&pdev->dev);

	clk_disable_unprepare(spifc->clk);

	pm_runtime_disable(&pdev->dev);



	return 0;

}



#ifdef CONFIG_PM_SLEEP

static int meson_spifc_suspend(struct device *dev)

{

	struct spi_master *master = dev_get_drvdata(dev);

	struct meson_spifc *spifc = spi_master_get_devdata(master);

	int ret;



	ret = spi_master_suspend(master);

	if (ret)

		return ret;



	if (!pm_runtime_suspended(dev))

		clk_disable_unprepare(spifc->clk);



	return 0;

}



static int meson_spifc_resume(struct device *dev)

{

	struct spi_master *master = dev_get_drvdata(dev);

	struct meson_spifc *spifc = spi_master_get_devdata(master);

	int ret;



	if (!pm_runtime_suspended(dev)) {

		ret = clk_prepare_enable(spifc->clk);

		if (ret)

			return ret;

	}



	meson_spifc_hw_init(spifc);



	ret = spi_master_resume(master);

	if (ret)

		clk_disable_unprepare(spifc->clk);



	return ret;

}

#endif /* CONFIG_PM_SLEEP */



#ifdef CONFIG_PM_RUNTIME

static int meson_spifc_runtime_suspend(struct device *dev)

{

	struct spi_master *master = dev_get_drvdata(dev);

	struct meson_spifc *spifc = spi_master_get_devdata(master);



	clk_disable_unprepare(spifc->clk);



	return 0;

}



static int meson_spifc_runtime_resume(struct device *dev)

{

	struct spi_master *master = dev_get_drvdata(dev);

	struct meson_spifc *spifc = spi_master_get_devdata(master);



	return clk_prepare_enable(spifc->clk);

}

#endif /* CONFIG_PM_RUNTIME */



static const struct dev_pm_ops meson_spifc_pm_ops = {

	SET_SYSTEM_SLEEP_PM_OPS(meson_spifc_suspend, meson_spifc_resume)

	SET_RUNTIME_PM_OPS(meson_spifc_runtime_suspend,

			   meson_spifc_runtime_resume,

			   NULL)

};



static const struct of_device_id meson_spifc_dt_match[] = {

	{ .compatible = "amlogic,meson6-spifc", },

	{ },

};



static struct platform_driver meson_spifc_driver = {

	.probe	= meson_spifc_probe,

	.remove	= meson_spifc_remove,

	.driver	= {

		.name		= "meson-spifc",

		.of_match_table	= of_match_ptr(meson_spifc_dt_match),

		.pm		= &meson_spifc_pm_ops,

	},

};



module_platform_driver(meson_spifc_driver);



MODULE_AUTHOR("Beniamino Galvani <b.galvani@gmail.com>");

MODULE_DESCRIPTION("Amlogic Meson SPIFC driver");

MODULE_LICENSE("GPL v2");

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