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

Viet Nga Dao
2015-03-16T08:46:48Z

On Fri, Mar 13, 2015 at 3:38 PM, Brian Norris
<computersforpeace@gmail.com> wrote:
> Hi Viet,
>
> On Wed, Feb 11, 2015 at 12:53:00PM +0800, Viet Nga Dao wrote:
>> From: Viet Nga Dao <vndao@altera.com>
>>
>> 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@altera.com>
>>
>> ---
>> 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.
>

There is no completion interrupt status register in this controller.
So i just checked again with hardware engineer. The illegal
write/erase interrupt status register can be read right after
write/erase operation. Hence, i will remove all the wait ready
functions.

>> + 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@altera.com>");
>> +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;
> };
>