Re: [PATCH v2] mtd:spi-nor: Add Altera EPCQ Driver

From: Brian Norris
Date: Fri Mar 13 2015 - 03:38:39 EST

Hi Viet,

On Wed, Feb 11, 2015 at 12:53:00PM +0800, Viet Nga Dao wrote:
> From: Viet Nga Dao <vndao@xxxxxxxxxx>
>
> Altera EPCQ Controller is a soft IP which enables access to Altera EPCQ and
> EPCS flash chips. This patch adds driver for these devices.
>
> Signed-off-by: VIET NGA DAO <vndao@xxxxxxxxxx>
>
> ---
> v2:
> - Change to spi_nor structure
> - Add lock and unlock functions for spi_nor
> - Simplify the altera_epcq_lock function
> - Replace reg by compatible in device tree
> ---
> .../devicetree/bindings/mtd/altera_epcq.txt | 45 ++
> drivers/mtd/spi-nor/Kconfig | 12 +
> drivers/mtd/spi-nor/Makefile | 1 +
> drivers/mtd/spi-nor/altera_epcq.c | 507 ++++++++++++++++++++
> drivers/mtd/spi-nor/altera_epcq.h | 116 +++++
> drivers/mtd/spi-nor/spi-nor.c | 86 ++++-
> include/linux/mtd/spi-nor.h | 3 +-
> 7 files changed, 764 insertions(+), 6 deletions(-)
> create mode 100644 Documentation/devicetree/bindings/mtd/altera_epcq.txt
> create mode 100644 drivers/mtd/spi-nor/altera_epcq.c
> create mode 100644 drivers/mtd/spi-nor/altera_epcq.h

Please split this up into at least 2 patches, if not 3. One or more for
the spi-nor changes, split logically; one for your new driver; and maybe
a separate one for the binding documentation.

Also, as Rafal noted, your patche is whitespace damaged, so I can't
apply or build it.

Please make sure you can apply, build, and run your patch on top of
l2-mtd.git:

http://git.infradead.org/l2-mtd.git
git://git.infradead.org/l2-mtd.git

...
> diff --git a/drivers/mtd/spi-nor/Kconfig b/drivers/mtd/spi-nor/Kconfig
> index 64a4f0e..83178b9 100644
> --- a/drivers/mtd/spi-nor/Kconfig
> +++ b/drivers/mtd/spi-nor/Kconfig
> @@ -28,4 +28,16 @@ config SPI_FSL_QUADSPI
> This enables support for the Quad SPI controller in master mode.
> We only connect the NOR to this controller now.
>
> +config SPI_ALTERA_EPCQ
> + tristate "Support Altera EPCQ/EPCS Flash chips"
> + depends on OF
> + help
> + This enables access to Altera EPCQ/EPCS flash chips, used for data
> + storage. See the driver source for the current list,
> + or to add other chips.
> +
> + If you want to compile this driver as a module ( = code which can be
> + inserted in and removed from the running kernel whenever you want),
> + say M here and read <file:Documentation/kbuild/modules.txt>.

I don't think you need to explain what a module is here. Look at other
Kconfig entries as examples, but I think you can just drop that last
paragraph.

> +
> endif # MTD_SPI_NOR
...
> diff --git a/drivers/mtd/spi-nor/altera_epcq.c
> b/drivers/mtd/spi-nor/altera_epcq.c
> new file mode 100644
> index 0000000..9db0d05
> --- /dev/null
> +++ b/drivers/mtd/spi-nor/altera_epcq.c
> @@ -0,0 +1,507 @@
> +/*
> + * Copyright (C) 2014 Altera 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/clk.h>
> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/errno.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/ioport.h>
> +#include <linux/jiffies.h>
> +#include <linux/kernel.h>
> +#include <linux/log2.h>
> +#include <linux/module.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/mtd/mtd.h>
> +#include <linux/mtd/partitions.h>
> +#include <linux/mtd/spi-nor.h>
> +#include <linux/mutex.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/platform_device.h>
> +#include <linux/sched.h>
> +
> +#include "altera_epcq.h"
> +
> +static int altera_epcq_write_reg(struct spi_nor *nor, u8 opcode, u8 *val,
> + int len, int wr_en)
> +{
> + return 0;
> +}
> +
> +static int altera_epcq_read_reg(struct spi_nor *nor, u8 opcode, u8 *val,
> + int len)
> +{
> + struct altera_epcq_flash *flash = nor->priv;
> + struct altera_epcq *dev = flash->priv;
> + u32 data = 0;
> + u8 id[5];
> +
> + switch (opcode) {
> + case SPINOR_OP_RDSR:
> + data = readl(dev->csr_base + EPCQ_SR_REG);
> + *val = (u8)data & EPCQ_SR_MASK;
> + break;
> + case SPINOR_OP_RDID:
> + /* opcode id */
> + if (dev->is_epcs) {
> + data = readl(dev->csr_base + EPCQ_SID_REG);
> + id[4] = EPCS_OPCODE_ID;
> + } else {
> + data = readl(dev->csr_base + EPCQ_RDID_REG);
> + id[4] = EPCQ_OPCODE_ID;
> + }

I think Rafal had some suggestions on changing how you match
IDs/devices. This, at least, doesn't look very good; you're faking a
particular ID, then matching it in spi-nor.c?

You might be better off doing something like the *-nonjedec entries in
spi-nor.c, and just match a string, similar to what Rafal mentioned I
think.

> + id[0] = 0xFF; /* non standard jedec id */
> + id[1] = 0xFF; /* non standard jedec id */
> + id[2] = 0xFF; /* non standard jedec id */
> + id[3] = (u8)data & EPCQ_ID_MASK; /* device id */
> + memcpy(val, &id, 5);
> + break;
> + default:

Is it dangerous to return indeterminate data here? Might want to at
least zero it out.

> + break;
> + }
> + return 0;
> +}
> +
> +static int altera_epcq_write_erase_check(struct spi_nor *nor,
> + bool write_erase)
> +{
> + struct altera_epcq_flash *flash = nor->priv;
> + struct altera_epcq *dev = flash->priv;
> + u32 val;
> + u32 mask;
> +
> + if (write_erase)
> + mask = EPCQ_ISR_ILLEGAL_WRITE_MASK;
> + else
> + mask = EPCQ_ISR_ILLEGAL_ERASE_MASK;
> +
> + val = readl(dev->csr_base + EPCQ_ISR_REG);
> + if (val & mask) {
> + dev_err(nor->dev,
> + "write/erase failed, sector might be protected\n");
> + /* clear this status for next use */
> + writel(val, dev->csr_base + EPCQ_ISR_REG);
> + return -EIO;
> + }
> + return 0;
> +}
> +
> +static int altera_epcq_addr_to_sector(struct mtd_info *mtd, int offset)
> +{
> + if (mtd->erasesize_shift)

Is mtd->erasesize_shift ever zero for you?

> + return offset >> mtd->erasesize_shift;
> + do_div(offset, mtd->erasesize);
> + return offset;
> +}
> +
> +static int altera_epcq_erase(struct spi_nor *nor, loff_t offset)
> +{
> +
> + struct altera_epcq_flash *flash = nor->priv;
> + struct altera_epcq *dev = flash->priv;
> + struct mtd_info *mtd = &flash->mtd;
> + u32 val;
> + int ret;
> + int sector_value;
> +
> + ret = nor->wait_till_ready(nor);

wait_till_ready() doesn't exist any more. And you shouldn't need to call
it here.

> + if (ret)
> + return ret;
> +
> + sector_value = altera_epcq_addr_to_sector(mtd, offset);
> + /* sanity check that block_offset is a valid sector number */
> + if (sector_value < 0)
> + return -EINVAL;
> +
> + /* sector value should occupy bits 17:8 */
> + val = (sector_value << 8) & EPCQ_MEM_OP_SECTOR_VALUE_MASK;
> +
> + /* sector erase commands occupies lower 2 bits */
> + val |= EPCQ_MEM_OP_SECTOR_ERASE_CMD;
> +
> + /* write sector erase command to EPCQ_MEM_OP register */
> + writel(val, dev->csr_base + EPCQ_MEM_OP_REG);
> +
> + /* wait the erase command is done then check whether
> + * write triggered a illegal write interrupt
> + */
> + ret = nor->wait_till_ready(nor);
> + if (ret)
> + return ret;
> +
> + ret = altera_epcq_write_erase_check(nor, 0);

This function looks like it's doing interrupt-based error reporting.
Do you have an IRQ you should be requesting for this driver? It seems
like you should be doing the following sequence:

1. begin write/erase
2. wait for an interrupt to signal completion
3. check interrupt status register for erase/write failure (e.g., locked
block)
4. return to spi-nor layer, which will read the flash status register

That way, you don't have to use the spi-nor "wait till ready" helpers,
which really aren't suited for this.

> + if (ret < 0)
> + return ret;
> +
> + return 0;
> +}
> +
> +static int altera_epcq_read(struct spi_nor *nor, loff_t from, size_t len,
> + size_t *retlen, u_char *buf)
> +{
> + struct altera_epcq_flash *flash = nor->priv;
> + struct altera_epcq *dev = flash->priv;
> + int ret = 0;
> +
> + mutex_lock(&flash->lock);

Hmm, why do you need this lock? I think spi-nor.c will do the per-flash
locking for you, so you can remove flash->lock throughout this driver.

> + /* wait till previous write/erase is done. */
> + ret = nor->wait_till_ready(nor);

Drop this.

> + if (ret)
> + goto err;
> +
> + memcpy_fromio(buf, dev->data_base + from, len);
> + *retlen = len;
> +
> +err:
> + mutex_unlock(&flash->lock);
> + return ret;
> +}
> +
> +static void altera_epcq_write(struct spi_nor *nor, loff_t to, size_t len,
> + size_t *retlen, const u_char *buf)
> +{
> + struct altera_epcq_flash *flash = nor->priv;
> + struct altera_epcq *dev = flash->priv;
> + int ret = 0;
> +
> + mutex_lock(&flash->lock);
> +
> + /* wait until finished previous write command */
> + ret = nor->wait_till_ready(nor);

Drop this. (Same throughout. I'll probably stop commenting.)

> + if (ret)
> + goto err;
> +
> + memcpy_toio(dev->data_base + to, buf, len);
> + *retlen += len;
> +
> + /* wait until finished write command then
> + * check whether write triggered a illegal write interrupt
> + */
> + ret = nor->wait_till_ready(nor);
> + if (ret)
> + goto err;
> +
> + ret = altera_epcq_write_erase_check(nor, 1);

Same comments as in the erase function. You probably need to do some
sort of interrupt handling, or else you'll need to handle the above
"wait_till_ready()" some other way.

> + if (ret < 0)
> + goto err;
> +
> +err:
> + mutex_unlock(&flash->lock);
> +}
> +
> +static int altera_epcq_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
> +{
> + struct altera_epcq_flash *flash = nor->priv;
> + struct altera_epcq *dev = flash->priv;
> + struct mtd_info *mtd = &flash->mtd;
> + uint32_t offset = ofs;
> + int ret = 0;
> + u32 sector_start, sector_end;
> + u32 num_sectors;
> + u32 mem_op;
> + u32 sr_bp;
> + u32 sr_tb;
> +
> + sector_start = offset;
> + sector_end = altera_epcq_addr_to_sector(mtd, offset + len);
> + num_sectors = mtd->size;
> + do_div(num_sectors, mtd->erasesize);
> +
> + dev_dbg(nor->dev, "%s: sector start is %u,sector end is %u\n",
> + __func__, sector_start, sector_end);
> +
> + mutex_lock(&flash->lock);
> + /* wait until finished previous write command. */
> + ret = nor->wait_till_ready(nor);
> + if (ret)
> + goto err;
> +
> + if (sector_start >= num_sectors / 2) {
> + sr_bp = fls(num_sectors - 1 - sector_start) + 1;
> + sr_tb = 0;
> + } else if ((sector_end < num_sectors / 2) && ~dev->is_epcs) {
> + sr_bp = fls(sector_end) + 1;
> + sr_tb = 1;
> + } else {
> + sr_bp = 16;
> + sr_tb = 0;
> + }
> +
> + mem_op = (sr_tb << 12) | (sr_bp << 8);
> + mem_op &= EPCQ_MEM_OP_SECTOR_PROTECT_VALUE_MASK;
> + mem_op |= EPCQ_MEM_OP_SECTOR_PROTECT_CMD;
> + writel(mem_op, dev->csr_base + EPCQ_MEM_OP_REG);
> +
> +err:
> + mutex_unlock(&flash->lock);
> + return ret;
> +}
> +
> +static int altera_epcq_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
> +{
> + struct altera_epcq_flash *flash = nor->priv;
> + struct altera_epcq *dev = flash->priv;
> + int ret = 0;
> + u32 mem_op;
> +
> + mutex_lock(&flash->lock);
> + /* wait until finished previous write command. */
> + ret = nor->wait_till_ready(nor);
> + if (ret)
> + goto err;
> + dev_info(nor->dev, "Unlock all protected area\n");
> + mem_op = 0;
> + mem_op &= EPCQ_MEM_OP_SECTOR_PROTECT_VALUE_MASK;
> + mem_op |= EPCQ_MEM_OP_SECTOR_PROTECT_CMD;
> + writel(mem_op, dev->csr_base + EPCQ_MEM_OP_REG);
> +
> +err:
> + mutex_unlock(&flash->lock);
> + return ret;
> +}
> +
> +static void altera_epcq_chip_select(struct altera_epcq *dev, u32 bank)
> +{
> + u32 val = 0;
> +
> + switch (bank) {
> + case 0:
> + val = EPCQ_CHIP_SELECT_0;
> + break;
> + case 1:
> + val = EPCQ_CHIP_SELECT_1;
> + break;
> + case 2:
> + val = EPCQ_CHIP_SELECT_2;
> + break;
> + default:
> + return;
> + }
> + writel(val, dev->csr_base + EPCQ_CHIP_SELECT_REG);
> +}
> +
> +
> +static int altera_epcq_probe_config_dt(struct platform_device *pdev,
> + struct device_node *np,
> + struct altera_epcq_plat_data *pdata)
> +{
> + struct device_node *pp = NULL;
> + struct resource *epcq_res;
> + int i = 0;
> +
> + pdata->is_epcs = of_property_read_bool(np, "is-epcs");
> +
> + epcq_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> + "csr_base");
> + pdata->csr_base = devm_ioremap_resource(&pdev->dev, epcq_res);
> + if (IS_ERR(pdata->csr_base)) {
> + dev_err(&pdev->dev, "%s: ERROR: failed to map csr base\n",
> + __func__);
> + return PTR_ERR(pdata->csr_base);
> + }
> +
> + epcq_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> + "data_base");
> + pdata->data_base = devm_ioremap_resource(&pdev->dev, epcq_res);
> + if (IS_ERR(pdata->data_base)) {
> + dev_err(&pdev->dev, "%s: ERROR: failed to map data base\n",
> + __func__);
> + return PTR_ERR(pdata->data_base);
> + }
> +
> + /* Fill structs for each subnode (flash device) */
> + for_each_available_child_of_node(np, pp) {
> + /* Read bank id from DT */
> + pdata->np[i] = pp;
> + i++;
> + }
> + pdata->num_flashes = i;
> + return 0;
> +}
> +
> +static int altera_epcq_setup_banks(struct platform_device *pdev,
> + u32 bank, struct device_node *np)
> +{
> + struct altera_epcq *dev = platform_get_drvdata(pdev);
> + struct mtd_part_parser_data ppdata = {};
> + struct altera_epcq_flash *flash;
> + struct spi_nor *nor;
> + int ret = 0;
> + char modalias[40];
> +
> + altera_epcq_chip_select(dev, bank);
> +
> + if (bank > dev->num_flashes - 1)
> + return -EINVAL;
> +
> + flash = devm_kzalloc(&pdev->dev, sizeof(*flash), GFP_KERNEL);
> + if (!flash)
> + return -ENOMEM;
> +
> + mutex_init(&flash->lock);
> +
> + dev->flash[bank] = flash;
> + nor = &flash->nor;
> + nor->mtd = &flash->mtd;
> + nor->dev = &pdev->dev;
> + nor->priv = flash;
> + flash->mtd.priv = nor;
> + flash->priv = dev;
> +
> + /* spi nor framework*/
> + nor->read_reg = altera_epcq_read_reg;
> + nor->write_reg = altera_epcq_write_reg;
> + nor->read = altera_epcq_read;
> + nor->write = altera_epcq_write;
> + nor->erase = altera_epcq_erase;
> + nor->_lock = altera_epcq_lock;
> + nor->_unlock = altera_epcq_unlock;
> +
> + if (of_modalias_node(np, modalias, sizeof(modalias)) < 0)
> + return -EINVAL;
> +
> + ret = spi_nor_scan(nor, modalias, SPI_NOR_QUAD);
> + if (ret)
> + return ret;
> + ppdata.of_node = np;
> +
> + return mtd_device_parse_register(&flash->mtd, NULL, &ppdata, NULL, 0);
> +}
> +
> +static int altera_epcq_probe(struct platform_device *pdev)
> +{
> + struct device_node *np = pdev->dev.of_node;
> + struct altera_epcq_plat_data *pdata = NULL;
> + struct altera_epcq *dev;
> + int ret = 0;
> + int i;
> +
> + if (!np) {
> + ret = -ENODEV;
> + dev_err(&pdev->dev, "no device found\n");
> + goto err;
> + }
> +
> + pdata = devm_kzalloc(&pdev->dev,
> + sizeof(struct altera_epcq_plat_data),
> + GFP_KERNEL);
> +
> + if (!pdata) {
> + ret = -ENOMEM;
> + goto err;
> + }
> +
> + ret = altera_epcq_probe_config_dt(pdev, np, pdata);
> + if (ret) {
> + ret = -ENODEV;
> + dev_err(&pdev->dev, "probe fail\n");
> + goto err;
> + }
> +
> + dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_ATOMIC);
> + if (!dev) {
> + ret = -ENOMEM;
> + goto err;
> + }
> + mutex_init(&dev->lock);
> + dev->is_epcs = pdata->is_epcs;
> + dev->csr_base = pdata->csr_base;
> + dev->data_base = pdata->data_base;
> +
> + /* check number of flashes */
> + dev->num_flashes = pdata->num_flashes;
> + if (dev->num_flashes > MAX_NUM_FLASH_CHIP) {
> + dev_err(&pdev->dev, "exceeding max number of flashes\n");
> + dev->num_flashes = MAX_NUM_FLASH_CHIP;
> + }
> +
> + /* check clock */
> + dev->clk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(dev->clk)) {
> + ret = PTR_ERR(dev->clk);
> + goto err;
> + }
> + ret = clk_prepare_enable(dev->clk);
> + if (ret)
> + goto err;
> +
> + platform_set_drvdata(pdev, dev);
> +
> + /* loop for each flash which is connected to epcq */
> + for (i = 0; i < dev->num_flashes; i++) {

I'm curious: are you doing any tests with multiple flashes
simultaneously?

> + ret = altera_epcq_setup_banks(pdev, i, pdata->np[i]);
> + if (ret) {
> + dev_err(&pdev->dev, "bank setup failed\n");
> + goto err_bank_setup;
> + }
> + }
> +
> + return 0;
> +
> +err_bank_setup:
> + clk_disable_unprepare(dev->clk);
> +err:
> + return ret;
> +}
> +
> +static int altera_epcq_remove(struct platform_device *pdev)
> +{
> + struct altera_epcq *dev;
> + struct altera_epcq_flash *flash;
> + int ret, i;
> +
> + dev = platform_get_drvdata(pdev);
> +
> + /* clean up for all nor flash */
> + for (i = 0; i < dev->num_flashes; i++) {
> + flash = dev->flash[i];
> + if (!flash)
> + continue;
> +
> + /* clean up mtd stuff */
> + ret = mtd_device_unregister(&flash->mtd);
> + if (ret)
> + dev_err(&pdev->dev, "error removing mtd\n");
> + }
> +
> + clk_disable_unprepare(dev->clk);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id altera_epcq_id_table[] = {
> + { .compatible = "altr,epcq-1.0" },
> + {}
> +};
> +MODULE_DEVICE_TABLE(of, altera_epcq_id_table);
> +
> +static struct platform_driver altera_epcq_driver = {
> + .driver = {
> + .name = ALTERA_EPCQ_RESOURCE_NAME,
> + .bus = &platform_bus_type,
> + .of_match_table = altera_epcq_id_table,
> + },
> + .probe = altera_epcq_probe,
> + .remove = altera_epcq_remove,
> +};
> +module_platform_driver(altera_epcq_driver);
> +
> +MODULE_AUTHOR("Viet Nga Dao <vndao@xxxxxxxxxx>");
> +MODULE_DESCRIPTION("Altera EPCQ Driver");
> +MODULE_LICENSE("GPL v2");
> diff --git a/drivers/mtd/spi-nor/altera_epcq.h
> b/drivers/mtd/spi-nor/altera_epcq.h
> new file mode 100644
> index 0000000..bc29f65
> --- /dev/null
> +++ b/drivers/mtd/spi-nor/altera_epcq.h

Do you need this to be a separate header? From what I can tell, it's all
private to the driver. So it may be better to merge the two.

[snip]

> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
> index 3b8a411..bfbb274 100644
> --- a/drivers/mtd/spi-nor/spi-nor.c
> +++ b/drivers/mtd/spi-nor/spi-nor.c
> @@ -330,7 +330,7 @@ erase_err:
> return ret;
> }
>
> -static int spi_nor_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
> +static int stmicro_spi_nor_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
> {
> struct spi_nor *nor = mtd_to_spi_nor(mtd);
> uint32_t offset = ofs;
> @@ -377,7 +377,8 @@ err:
> return ret;
> }
>
> -static int spi_nor_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
> +static int stmicro_spi_nor_unlock(struct mtd_info *mtd, loff_t ofs,
> + uint64_t len)
> {
> struct spi_nor *nor = mtd_to_spi_nor(mtd);
> uint32_t offset = ofs;
> @@ -424,6 +425,48 @@ err:
> return ret;
> }
>
> +static int spi_nor_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
> +{
> + struct spi_nor *nor = mtd_to_spi_nor(mtd);
> + int ret = 0;
> +
> + ret = spi_nor_lock_and_prep(nor, SPI_NOR_OPS_LOCK);
> + if (ret)
> + return ret;
> +
> + /* Wait until finished previous command */
> + ret = wait_till_ready(nor);
> + if (ret)
> + goto err;
> +
> + ret = nor->_lock(nor, ofs, len);
> +
> +err:
> + spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_LOCK);
> + return ret;
> +}
> +
> +static int spi_nor_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
> +{
> + struct spi_nor *nor = mtd_to_spi_nor(mtd);
> + int ret = 0;
> +
> + ret = spi_nor_lock_and_prep(nor, SPI_NOR_OPS_LOCK);
> + if (ret)
> + return ret;
> +
> + /* Wait until finished previous command */
> + ret = wait_till_ready(nor);
> + if (ret)
> + goto err;
> +
> + ret = nor->_unlock(nor, ofs, len);
> +
> +err:
> + spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_LOCK);
> + return ret;
> +}
> +
> struct flash_info {
> /* JEDEC id zero means "no ID" (most older chips); otherwise it has
> * a high byte of zero plus three data bytes: the manufacturer id,
...
> @@ -904,7 +977,8 @@ static void spi_nor_shutdown(struct spi_nor *nor)
> static int spi_nor_check(struct spi_nor *nor)
> {
> if (!nor->dev || !nor->read || !nor->write ||
> - !nor->read_reg || !nor->write_reg || !nor->erase) {
> + !nor->read_reg || !nor->write_reg || !nor->erase ||
> + !nor->_lock || !nor->_unlock) {

No, lock() and unlock() are optional and should not be required here.

> pr_err("spi-nor: please fill all the necessary fields!\n");
> return -EINVAL;
> }
[...]
> @@ -987,6 +1060,9 @@ int spi_nor_scan(struct spi_nor *nor, const char
> *name, enum read_mode mode)
>
> /* nor protection support for STmicro chips */
> if (JEDEC_MFR(info->jedec_id) == CFI_MFR_ST) {
> + mtd->_lock = stmicro_spi_nor_lock;
> + mtd->_unlock = stmicro_spi_nor_unlock;
> + } else {
> mtd->_lock = spi_nor_lock;
> mtd->_unlock = spi_nor_unlock;
> }

No, you can't just magically create a lock() and unlock() function for
all non-ST flash here. You need to only assign this when you *know* the
flash supports lock/unlock.

> diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
> index 29d1a0d..042bed2 100644
> --- a/include/linux/mtd/spi-nor.h
> +++ b/include/linux/mtd/spi-nor.h
> @@ -183,7 +183,8 @@ struct spi_nor {
> void (*write)(struct spi_nor *nor, loff_t to,
> size_t len, size_t *retlen, const u_char *write_buf);
> int (*erase)(struct spi_nor *nor, loff_t offs);
> -
> + int (*_lock)(struct spi_nor *nor, loff_t offs, uint64_t len);
> + int (*_unlock)(struct spi_nor *nor, loff_t offs, uint64_t len);

You need to document new fields in the comments.

> void *priv;
> };
>

All in all, I think your spi-nor lock/unlock changes should be rewritten
a bit to be safer (i.e., apply only to flash that support it) and to
require less duplication (particularly on the locking). How about the
following? I've only compile-tested it, but it should now allow you to
supply nor->flash_lock() and nor->flash_unlock() implementations in your
driver.

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index b6a5a0c269e1..60bf3caf1ead 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -369,17 +369,13 @@ erase_err:
return ret;
}

-static int spi_nor_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
+static int stm_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
{
- struct spi_nor *nor = mtd_to_spi_nor(mtd);
+ struct mtd_info *mtd = nor->mtd;
uint32_t offset = ofs;
uint8_t status_old, status_new;
int ret = 0;

- ret = spi_nor_lock_and_prep(nor, SPI_NOR_OPS_LOCK);
- if (ret)
- return ret;
-
status_old = read_sr(nor);

if (offset < mtd->size - (mtd->size / 2))
@@ -402,26 +398,18 @@ static int spi_nor_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
(status_old & (SR_BP2 | SR_BP1 | SR_BP0))) {
write_enable(nor);
ret = write_sr(nor, status_new);
- if (ret)
- goto err;
}

-err:
- spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_LOCK);
return ret;
}

-static int spi_nor_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
+static int stm_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
{
- struct spi_nor *nor = mtd_to_spi_nor(mtd);
+ struct mtd_info *mtd = nor->mtd;
uint32_t offset = ofs;
uint8_t status_old, status_new;
int ret = 0;

- ret = spi_nor_lock_and_prep(nor, SPI_NOR_OPS_UNLOCK);
- if (ret)
- return ret;
-
status_old = read_sr(nor);

if (offset+len > mtd->size - (mtd->size / 64))
@@ -444,15 +432,41 @@ static int spi_nor_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
(status_old & (SR_BP2 | SR_BP1 | SR_BP0))) {
write_enable(nor);
ret = write_sr(nor, status_new);
- if (ret)
- goto err;
}

-err:
+ return ret;
+}
+
+static int spi_nor_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
+{
+ struct spi_nor *nor = mtd_to_spi_nor(mtd);
+ int ret;
+
+ ret = spi_nor_lock_and_prep(nor, SPI_NOR_OPS_LOCK);
+ if (ret)
+ return ret;
+
+ ret = nor->flash_lock(nor, ofs, len);
+
spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_UNLOCK);
return ret;
}

+static int spi_nor_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
+{
+ struct spi_nor *nor = mtd_to_spi_nor(mtd);
+ int ret;
+
+ ret = spi_nor_lock_and_prep(nor, SPI_NOR_OPS_UNLOCK);
+ if (ret)
+ return ret;
+
+ ret = nor->flash_unlock(nor, ofs, len);
+
+ spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_LOCK);
+ return ret;
+}
+
/* Used when the "_ext_id" is two bytes at most */
#define INFO(_jedec_id, _ext_id, _sector_size, _n_sectors, _flags) \
((kernel_ulong_t)&(struct flash_info) { \
@@ -1045,6 +1059,11 @@ int spi_nor_scan(struct spi_nor *nor, const char *name, enum read_mode mode)

/* nor protection support for STmicro chips */
if (JEDEC_MFR(info) == CFI_MFR_ST) {
+ nor->flash_lock = stm_lock;
+ nor->flash_unlock = stm_unlock;
+ }
+
+ if (nor->flash_lock && nor->flash_unlock) {
mtd->_lock = spi_nor_lock;
mtd->_unlock = spi_nor_unlock;
}
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index 4720b86ee73d..e5409524bb0a 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -155,6 +155,8 @@ enum spi_nor_option_flags {
* @write: [DRIVER-SPECIFIC] write data to the SPI NOR
* @erase: [DRIVER-SPECIFIC] erase a sector of the SPI NOR
* at the offset @offs
+ * @lock: [FLASH-SPECIFIC] lock a region of the SPI NOR
+ * @unlock: [FLASH-SPECIFIC] unlock a region of the SPI NOR
* @priv: the private data
*/
struct spi_nor {
@@ -189,6 +191,9 @@ struct spi_nor {
size_t len, size_t *retlen, const u_char *write_buf);
int (*erase)(struct spi_nor *nor, loff_t offs);

+ int (*flash_lock)(struct spi_nor *nor, loff_t ofs, uint64_t len);
+ int (*flash_unlock)(struct spi_nor *nor, loff_t ofs, uint64_t len);
+
void *priv;
};

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