Re: [PATCH] mtd: nand: Add OX820 NAND Support

[Neil Armstrong]

On 10/19/2016 04:55 PM, Neil Armstrong wrote:
> Add NAND driver to support the Oxford Semiconductor OX820 NAND Controller.
> This is a simple memory mapped NAND controller with single chip select and
> software ECC.
> 
> Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>

Forgot
Acked-by: Rob Herring <robh@xxxxxxxxxx>

Will add in v2 if a respin is needed.

> ---
>  .../devicetree/bindings/mtd/oxnas-nand.txt         |  24 +++
>  drivers/mtd/nand/Kconfig                           |   5 +
>  drivers/mtd/nand/Makefile                          |   1 +
>  drivers/mtd/nand/oxnas_nand.c                      | 204 +++++++++++++++++++++
>  4 files changed, 234 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/mtd/oxnas-nand.txt
>  create mode 100644 drivers/mtd/nand/oxnas_nand.c
> 
> Changes since RFC http://lkml.kernel.org/r/20161018090927.1990-1-narmstrong@xxxxxxxxxxxx :
>  - Avoid using chip->IO_ADDR*
>  - Use new DT structure
>  - Assign a chip for the subnode
>  - Use the nand_hw_control structure
>  - Cleanup probe
>  - Cleanup cmd_ctrl by using a context ctrl offset used in write_bytes
> 
> diff --git a/Documentation/devicetree/bindings/mtd/oxnas-nand.txt b/Documentation/devicetree/bindings/mtd/oxnas-nand.txt
> new file mode 100644
> index 0000000..83b684d
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mtd/oxnas-nand.txt
> @@ -0,0 +1,24 @@
> +* Oxford Semiconductor OXNAS NAND Controller
> +
> +Please refer to nand.txt for generic information regarding MTD NAND bindings.
> +
> +Required properties:
> + - compatible: "oxsemi,ox820-nand"
> + - reg: Base address and length for NAND mapped memory.
> +
> +Optional Properties:
> + - clocks: phandle to the NAND gate clock if needed.
> + - resets: phandle to the NAND reset control if needed.
> +
> +Example:
> +
> +nand: nand@41000000 {
> +	compatible = "oxsemi,ox820-nand";
> +	reg = <0x41000000 0x100000>;
> +	nand-ecc-mode = "soft";
> +	clocks = <&stdclk CLK_820_NAND>;
> +	resets = <&reset RESET_NAND>;
> +	#address-cells = <1>;
> +	#size-cells = <1>;
> +	status = "disabled";
> +};
> diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
> index 7b7a887..c023125 100644
> --- a/drivers/mtd/nand/Kconfig
> +++ b/drivers/mtd/nand/Kconfig
> @@ -426,6 +426,11 @@ config MTD_NAND_ORION
>  	  No board specific support is done by this driver, each board
>  	  must advertise a platform_device for the driver to attach.
>  
> +config MTD_NAND_OXNAS
> +	tristate "NAND Flash support for Oxford Semiconductor SoC"
> +	help
> +	  This enables the NAND flash controller on Oxford Semiconductor SoCs.
> +
>  config MTD_NAND_FSL_ELBC
>  	tristate "NAND support for Freescale eLBC controllers"
>  	depends on FSL_SOC
> diff --git a/drivers/mtd/nand/Makefile b/drivers/mtd/nand/Makefile
> index cafde6f..05fc054 100644
> --- a/drivers/mtd/nand/Makefile
> +++ b/drivers/mtd/nand/Makefile
> @@ -35,6 +35,7 @@ obj-$(CONFIG_MTD_NAND_TMIO)		+= tmio_nand.o
>  obj-$(CONFIG_MTD_NAND_PLATFORM)		+= plat_nand.o
>  obj-$(CONFIG_MTD_NAND_PASEMI)		+= pasemi_nand.o
>  obj-$(CONFIG_MTD_NAND_ORION)		+= orion_nand.o
> +obj-$(CONFIG_MTD_NAND_OXNAS)		+= oxnas_nand.o
>  obj-$(CONFIG_MTD_NAND_FSL_ELBC)		+= fsl_elbc_nand.o
>  obj-$(CONFIG_MTD_NAND_FSL_IFC)		+= fsl_ifc_nand.o
>  obj-$(CONFIG_MTD_NAND_FSL_UPM)		+= fsl_upm.o
> diff --git a/drivers/mtd/nand/oxnas_nand.c b/drivers/mtd/nand/oxnas_nand.c
> new file mode 100644
> index 0000000..a9fe1ac
> --- /dev/null
> +++ b/drivers/mtd/nand/oxnas_nand.c
> @@ -0,0 +1,204 @@
> +/*
> + * Oxford Semiconductor OXNAS NAND driver
> +
> + * Copyright (C) 2016 Neil Armstrong <narmstrong@xxxxxxxxxxxx>
> + * Heavily based on plat_nand.c :
> + * Author: Vitaly Wool <vitalywool@xxxxxxxxx>
> + * Copyright (C) 2013 Ma Haijun <mahaijuns@xxxxxxxxx>
> + * Copyright (C) 2012 John Crispin <blogic@xxxxxxxxxxx>
> + *
> + * 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.
> + *
> + */
> +
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +#include <linux/clk.h>
> +#include <linux/reset.h>
> +#include <linux/mtd/mtd.h>
> +#include <linux/mtd/nand.h>
> +#include <linux/mtd/partitions.h>
> +#include <linux/of.h>
> +
> +/* Nand commands */
> +#define OXNAS_NAND_CMD_ALE		BIT(18)
> +#define OXNAS_NAND_CMD_CLE		BIT(19)
> +
> +#define OXNAS_NAND_MAX_CHIPS	1
> +
> +struct oxnas_nand {
> +	struct nand_hw_control base;
> +	void __iomem *io_base;
> +	struct clk *clk;
> +	struct nand_chip *chips[OXNAS_NAND_MAX_CHIPS];
> +	unsigned long ctrl;
> +};
> +
> +static uint8_t oxnas_nand_read_byte(struct mtd_info *mtd)
> +{
> +	struct nand_chip *chip = mtd_to_nand(mtd);
> +	struct oxnas_nand *oxnas = nand_get_controller_data(chip);
> +
> +	return readb(oxnas->io_base);
> +}
> +
> +static void oxnas_nand_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
> +{
> +	struct nand_chip *chip = mtd_to_nand(mtd);
> +	struct oxnas_nand *oxnas = nand_get_controller_data(chip);
> +
> +	ioread8_rep(oxnas->io_base, buf, len);
> +}
> +
> +static void oxnas_nand_write_buf(struct mtd_info *mtd,
> +				 const uint8_t *buf, int len)
> +{
> +	struct nand_chip *chip = mtd_to_nand(mtd);
> +	struct oxnas_nand *oxnas = nand_get_controller_data(chip);
> +
> +	iowrite8_rep(oxnas->io_base + oxnas->ctrl, buf, len);
> +}
> +
> +/* Single CS command control */
> +static void oxnas_nand_cmd_ctrl(struct mtd_info *mtd, int cmd,
> +				unsigned int ctrl)
> +{
> +	struct nand_chip *chip = mtd_to_nand(mtd);
> +	struct oxnas_nand *oxnas = nand_get_controller_data(chip);
> +
> +	if (ctrl & NAND_CTRL_CHANGE) {
> +		if (ctrl & NAND_CLE)
> +			oxnas->ctrl = OXNAS_NAND_CMD_CLE;
> +		else if (ctrl & NAND_ALE)
> +			oxnas->ctrl = OXNAS_NAND_CMD_ALE;
> +		else
> +			oxnas->ctrl = 0;
> +	}
> +
> +	if (cmd != NAND_CMD_NONE)
> +		writeb(cmd, oxnas->io_base + oxnas->ctrl);
> +}
> +
> +/*
> + * Probe for the NAND device.
> + */
> +static int oxnas_nand_probe(struct platform_device *pdev)
> +{
> +	struct device_node *np = pdev->dev.of_node;
> +	struct device_node *nand_np;
> +	struct oxnas_nand *oxnas;
> +	struct nand_chip *chip;
> +	struct mtd_info *mtd;
> +	struct resource *res;
> +	int nchips = 0;
> +	int count = 0;
> +	int err = 0;
> +
> +	/* Allocate memory for the device structure (and zero it) */
> +	oxnas = devm_kzalloc(&pdev->dev, sizeof(struct nand_chip),
> +			    GFP_KERNEL);
> +	if (!oxnas)
> +		return -ENOMEM;
> +
> +	nand_hw_control_init(&oxnas->base);
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	oxnas->io_base = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(oxnas->io_base))
> +		return PTR_ERR(oxnas->io_base);
> +
> +	oxnas->clk = devm_clk_get(&pdev->dev, NULL);
> +	if (IS_ERR(oxnas->clk))
> +		oxnas->clk = NULL;
> +
> +	/* Only a single chip node is supported */
> +	count = of_get_child_count(np);
> +	if (count > 1)
> +		return -EINVAL;
> +
> +	clk_prepare_enable(oxnas->clk);
> +	device_reset_optional(&pdev->dev);
> +
> +	for_each_child_of_node(np, nand_np) {
> +		chip = devm_kzalloc(&pdev->dev, sizeof(struct nand_chip),
> +				    GFP_KERNEL);
> +		if (!chip)
> +			return -ENOMEM;
> +
> +		chip->controller = &oxnas->base;
> +
> +		nand_set_flash_node(chip, nand_np);
> +		nand_set_controller_data(chip, oxnas);
> +
> +		mtd = nand_to_mtd(chip);
> +		mtd->dev.parent = &pdev->dev;
> +		mtd->priv = chip;
> +
> +		chip->cmd_ctrl = oxnas_nand_cmd_ctrl;
> +		chip->read_buf = oxnas_nand_read_buf;
> +		chip->read_byte = oxnas_nand_read_byte;
> +		chip->write_buf = oxnas_nand_write_buf;
> +		chip->chip_delay = 30;
> +
> +		/* Scan to find existence of the device */
> +		err = nand_scan(mtd, 1);
> +		if (err)
> +			return err;
> +
> +		err = mtd_device_register(mtd, NULL, 0);
> +		if (err) {
> +			nand_release(mtd);
> +			return err;
> +		}
> +
> +		oxnas->chips[nchips] = chip;
> +		++nchips;
> +	}
> +
> +	/* Exit if no chips found */
> +	if (!nchips)
> +		return -ENODEV;
> +
> +	platform_set_drvdata(pdev, oxnas);
> +
> +	return 0;
> +}
> +
> +static int oxnas_nand_remove(struct platform_device *pdev)
> +{
> +	struct oxnas_nand *oxnas = platform_get_drvdata(pdev);
> +
> +	if (oxnas->chips[0])
> +		nand_release(nand_to_mtd(oxnas->chips[0]));
> +
> +	clk_disable_unprepare(oxnas->clk);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id oxnas_nand_match[] = {
> +	{ .compatible = "oxsemi,ox820-nand" },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, oxnas_nand_match);
> +
> +static struct platform_driver oxnas_nand_driver = {
> +	.probe	= oxnas_nand_probe,
> +	.remove	= oxnas_nand_remove,
> +	.driver	= {
> +		.name		= "oxnas_nand",
> +		.of_match_table = oxnas_nand_match,
> +	},
> +};
> +
> +module_platform_driver(oxnas_nand_driver);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Neil Armstrong <narmstrong@xxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("Oxnas NAND driver");
> +MODULE_ALIAS("platform:oxnas_nand");
>