Re: [PATCH v4] mtd: rawnand: macronix: OTP access for MX30LFxG18AC

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Hello Miquel and Jaime!

On 14.06.2023 12:10, Miquel Raynal wrote:
> Hi liao,
> 
> jaimeliao.tw@xxxxxxxxx wrote on Wed, 14 Jun 2023 17:06:16 +0800:
> 
>> Hi Miquel
>>
>>
>>>
>>> Hello,
>>>
>>> AVKrasnov@xxxxxxxxxxxxxx wrote on Tue, 23 May 2023 13:16:34 +0300:
>>>  
>>>> This adds support for OTP area access on MX30LFxG18AC chip series.  
>>>
>>> Jaime, any feedback on this? Will you test it?
>>>
>>> How are we supposed to test the OTP is locked? I see this is still an
>>> open point.  
>> After checking with internal, sub feature parameter are volatile register.
>>
>> It could be change after enter/exit OTP region or power cycle even OTP
>>
>> region have been locked.
>>
>> OTP operation mode still could be enter/exit and region is read only
>> after OTP in protect mode.
>>
>> #program command could execute but no use after setting OTP region in
>> protect mode.
>>
>> So that we can't check whether OTP region is locked via get feature.
>>
>> And we don't have region for checking status of OTP locked.
> 
> Ah, too bad. But thanks a lot for the explanation. Arseniy, can you
> please change your comment to explain that the bit is volatile and thus
> there is no way to check if an otp region is locked? I would return
> EOPNOTSUPP in this case and verify that the core cleanly handles the
> situation.

Ok, thanks for details. @Miquel, ok, I'll change comment from "don't know..."
to this explanation. About EOPNOTSUPP, IIUC I think it is not good way to
suppress '_get_fact_prot_info' and '_get_user_prot_info' callbacks with this
return code as it is the only way to know size of OTP region.

Thanks, Arseniy

> 
> Thanks,
> Miquèl
> 
>>
>>>  
>>>>
>>>> Signed-off-by: Arseniy Krasnov <AVKrasnov@xxxxxxxxxxxxxx>
>>>> ---
>>>>   v1 -> v2:
>>>>   * Add slab.h include due to kernel test robot error.
>>>>   v2 -> v3:
>>>>   * Use 'uint64_t' as input argument for 'do_div()' instead
>>>>     of 'unsigned long' due to kernel test robot error.
>>>>   v3 -> v4:
>>>>   * Use 'dev_err()' instead of 'WARN()'.
>>>>   * Call 'match_string()' before checking 'supports_set_get_features'
>>>>     in 'macronix_nand_setup_otp().
>>>>   * Use 'u8' instead of 'uint8_t' as ./checkpatch.pl wants.
>>>>
>>>>  drivers/mtd/nand/raw/nand_macronix.c | 216 +++++++++++++++++++++++++++
>>>>  1 file changed, 216 insertions(+)
>>>>
>>>> diff --git a/drivers/mtd/nand/raw/nand_macronix.c b/drivers/mtd/nand/raw/nand_macronix.c
>>>> index 1472f925f386..be1ffa93bebb 100644
>>>> --- a/drivers/mtd/nand/raw/nand_macronix.c
>>>> +++ b/drivers/mtd/nand/raw/nand_macronix.c
>>>> @@ -6,6 +6,7 @@
>>>>   * Author: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx>
>>>>   */
>>>>
>>>> +#include <linux/slab.h>
>>>>  #include "linux/delay.h"
>>>>  #include "internals.h"
>>>>
>>>> @@ -31,6 +32,20 @@
>>>>
>>>>  #define MXIC_CMD_POWER_DOWN 0xB9
>>>>
>>>> +#define ONFI_FEATURE_ADDR_30LFXG18AC_OTP     0x90
>>>> +#define MACRONIX_30LFXG18AC_OTP_START_PAGE   0
>>>> +#define MACRONIX_30LFXG18AC_OTP_PAGES                30
>>>> +#define MACRONIX_30LFXG18AC_OTP_PAGE_SIZE    2112
>>>> +#define MACRONIX_30LFXG18AC_OTP_START_BYTE   \
>>>> +     (MACRONIX_30LFXG18AC_OTP_START_PAGE *   \
>>>> +      MACRONIX_30LFXG18AC_OTP_PAGE_SIZE)
>>>> +#define MACRONIX_30LFXG18AC_OTP_SIZE_BYTES   \
>>>> +     (MACRONIX_30LFXG18AC_OTP_PAGES *        \
>>>> +      MACRONIX_30LFXG18AC_OTP_PAGE_SIZE)
>>>> +
>>>> +#define MACRONIX_30LFXG18AC_OTP_EN           BIT(0)
>>>> +#define MACRONIX_30LFXG18AC_OTP_LOCKED               BIT(1)
>>>> +
>>>>  struct nand_onfi_vendor_macronix {
>>>>       u8 reserved;
>>>>       u8 reliability_func;
>>>> @@ -316,6 +331,206 @@ static void macronix_nand_deep_power_down_support(struct nand_chip *chip)
>>>>       chip->ops.resume = mxic_nand_resume;
>>>>  }
>>>>
>>>> +static int macronix_30lfxg18ac_get_otp_info(struct mtd_info *mtd, size_t len,
>>>> +                                         size_t *retlen,
>>>> +                                         struct otp_info *buf)
>>>> +{
>>>> +     if (len < sizeof(*buf))
>>>> +             return -EINVAL;
>>>> +
>>>> +     /* Don't know how to check that OTP is locked. */
>>>> +     buf->locked = 0;
>>>> +     buf->start = MACRONIX_30LFXG18AC_OTP_START_BYTE;
>>>> +     buf->length = MACRONIX_30LFXG18AC_OTP_SIZE_BYTES;
>>>> +
>>>> +     *retlen = sizeof(*buf);
>>>> +
>>>> +     return 0;
>>>> +}
>>>> +
>>>> +static int macronix_30lfxg18ac_otp_enable(struct nand_chip *nand)
>>>> +{
>>>> +     u8 feature_buf[ONFI_SUBFEATURE_PARAM_LEN] = { 0 };
>>>> +
>>>> +     feature_buf[0] = MACRONIX_30LFXG18AC_OTP_EN;
>>>> +     return nand_set_features(nand, ONFI_FEATURE_ADDR_30LFXG18AC_OTP,
>>>> +                              feature_buf);
>>>> +}
>>>> +
>>>> +static int macronix_30lfxg18ac_otp_disable(struct nand_chip *nand)
>>>> +{
>>>> +     u8 feature_buf[ONFI_SUBFEATURE_PARAM_LEN] = { 0 };
>>>> +
>>>> +     return nand_set_features(nand, ONFI_FEATURE_ADDR_30LFXG18AC_OTP,
>>>> +                              feature_buf);
>>>> +}
>>>> +
>>>> +static int __macronix_30lfxg18ac_rw_otp(struct mtd_info *mtd,
>>>> +                                     loff_t offs_in_flash,
>>>> +                                     size_t len, size_t *retlen,
>>>> +                                     u_char *buf, bool write)
>>>> +{
>>>> +     struct nand_chip *nand;
>>>> +     size_t bytes_handled;
>>>> +     off_t offs_in_page;
>>>> +     void *dma_buf;
>>>> +     u64 page;
>>>> +     int ret;
>>>> +
>>>> +     /* 'nand_prog/read_page_op()' may use 'buf' as DMA buffer,
>>>> +      * so allocate properly aligned memory for it. This is
>>>> +      * needed because cross page accesses may lead to unaligned
>>>> +      * buffer address for DMA.
>>>> +      */
>>>> +     dma_buf = kmalloc(MACRONIX_30LFXG18AC_OTP_PAGE_SIZE, GFP_KERNEL);
>>>> +     if (!dma_buf)
>>>> +             return -ENOMEM;
>>>> +
>>>> +     nand = mtd_to_nand(mtd);
>>>> +     nand_select_target(nand, 0);
>>>> +
>>>> +     ret = macronix_30lfxg18ac_otp_enable(nand);
>>>> +     if (ret)
>>>> +             goto out_otp;
>>>> +
>>>> +     page = offs_in_flash;
>>>> +     /* 'page' will be result of division. */
>>>> +     offs_in_page = do_div(page, MACRONIX_30LFXG18AC_OTP_PAGE_SIZE);
>>>> +     bytes_handled = 0;
>>>> +
>>>> +     while (bytes_handled < len &&
>>>> +            page < MACRONIX_30LFXG18AC_OTP_PAGES) {
>>>> +             size_t bytes_to_handle;
>>>> +
>>>> +             bytes_to_handle = min_t(size_t, len - bytes_handled,
>>>> +                                     MACRONIX_30LFXG18AC_OTP_PAGE_SIZE -
>>>> +                                     offs_in_page);
>>>> +
>>>> +             if (write) {
>>>> +                     memcpy(dma_buf, &buf[bytes_handled], bytes_to_handle);
>>>> +                     ret = nand_prog_page_op(nand, page, offs_in_page,
>>>> +                                             dma_buf, bytes_to_handle);
>>>> +             } else {
>>>> +                     ret = nand_read_page_op(nand, page, offs_in_page,
>>>> +                                             dma_buf, bytes_to_handle);
>>>> +                     if (!ret)
>>>> +                             memcpy(&buf[bytes_handled], dma_buf,
>>>> +                                    bytes_to_handle);
>>>> +             }
>>>> +             if (ret)
>>>> +                     goto out_otp;
>>>> +
>>>> +             bytes_handled += bytes_to_handle;
>>>> +             offs_in_page = 0;
>>>> +             page++;
>>>> +     }
>>>> +
>>>> +     *retlen = bytes_handled;
>>>> +
>>>> +out_otp:
>>>> +     if (ret)
>>>> +             dev_err(&mtd->dev, "failed to perform OTP IO: %i\n", ret);
>>>> +
>>>> +     ret = macronix_30lfxg18ac_otp_disable(nand);
>>>> +     if (ret)
>>>> +             dev_err(&mtd->dev, "failed to leave OTP mode after %s\n",
>>>> +                     write ? "write" : "read");
>>>> +
>>>> +     nand_deselect_target(nand);
>>>> +     kfree(dma_buf);
>>>> +
>>>> +     return ret;
>>>> +}
>>>> +
>>>> +static int macronix_30lfxg18ac_write_otp(struct mtd_info *mtd, loff_t to,
>>>> +                                      size_t len, size_t *rlen,
>>>> +                                      const u_char *buf)
>>>> +{
>>>> +     return __macronix_30lfxg18ac_rw_otp(mtd, to, len, rlen, (u_char *)buf,
>>>> +                                         true);
>>>> +}
>>>> +
>>>> +static int macronix_30lfxg18ac_read_otp(struct mtd_info *mtd, loff_t from,
>>>> +                                     size_t len, size_t *rlen,
>>>> +                                     u_char *buf)
>>>> +{
>>>> +     return __macronix_30lfxg18ac_rw_otp(mtd, from, len, rlen, buf, false);
>>>> +}
>>>> +
>>>> +static int macronix_30lfxg18ac_lock_otp(struct mtd_info *mtd, loff_t from,
>>>> +                                     size_t len)
>>>> +{
>>>> +     u8 feature_buf[ONFI_SUBFEATURE_PARAM_LEN] = { 0 };
>>>> +     struct nand_chip *nand;
>>>> +     int ret;
>>>> +
>>>> +     if (from != MACRONIX_30LFXG18AC_OTP_START_BYTE ||
>>>> +         len != MACRONIX_30LFXG18AC_OTP_SIZE_BYTES)
>>>> +             return -EINVAL;
>>>> +
>>>> +     dev_dbg(&mtd->dev, "locking OTP\n");
>>>> +
>>>> +     nand = mtd_to_nand(mtd);
>>>> +     nand_select_target(nand, 0);
>>>> +
>>>> +     feature_buf[0] = MACRONIX_30LFXG18AC_OTP_EN |
>>>> +                      MACRONIX_30LFXG18AC_OTP_LOCKED;
>>>> +     ret = nand_set_features(nand, ONFI_FEATURE_ADDR_30LFXG18AC_OTP,
>>>> +                             feature_buf);
>>>> +     if (ret) {
>>>> +             dev_err(&mtd->dev,
>>>> +                     "failed to lock OTP (set features): %i\n", ret);
>>>> +             nand_deselect_target(nand);
>>>> +             return ret;
>>>> +     }
>>>> +
>>>> +     /* Do dummy page prog with zero address. */
>>>> +     feature_buf[0] = 0;
>>>> +     ret = nand_prog_page_op(nand, 0, 0, feature_buf, 1);
>>>> +     if (ret)
>>>> +             dev_err(&mtd->dev,
>>>> +                     "failed to lock OTP (page prog): %i\n", ret);
>>>> +
>>>> +     ret = macronix_30lfxg18ac_otp_disable(nand);
>>>> +     if (ret)
>>>> +             dev_err(&mtd->dev, "failed to leave OTP mode after lock\n");
>>>> +
>>>> +     nand_deselect_target(nand);
>>>> +
>>>> +     return ret;
>>>> +}
>>>> +
>>>> +static void macronix_nand_setup_otp(struct nand_chip *chip)
>>>> +{
>>>> +     static const char * const supported_otp_models[] = {
>>>> +             "MX30LF1G18AC",
>>>> +             "MX30LF2G18AC",
>>>> +             "MX30LF4G18AC",
>>>> +     };
>>>> +     struct mtd_info *mtd;
>>>> +
>>>> +     if (match_string(supported_otp_models,
>>>> +                      ARRAY_SIZE(supported_otp_models),
>>>> +                      chip->parameters.model) < 0)
>>>> +             return;
>>>> +
>>>> +     if (!chip->parameters.supports_set_get_features)
>>>> +             return;
>>>> +
>>>> +     bitmap_set(chip->parameters.get_feature_list,
>>>> +                ONFI_FEATURE_ADDR_30LFXG18AC_OTP, 1);
>>>> +     bitmap_set(chip->parameters.set_feature_list,
>>>> +                ONFI_FEATURE_ADDR_30LFXG18AC_OTP, 1);
>>>> +
>>>> +     mtd = nand_to_mtd(chip);
>>>> +     mtd->_get_fact_prot_info = macronix_30lfxg18ac_get_otp_info;
>>>> +     mtd->_read_fact_prot_reg = macronix_30lfxg18ac_read_otp;
>>>> +     mtd->_get_user_prot_info = macronix_30lfxg18ac_get_otp_info;
>>>> +     mtd->_read_user_prot_reg = macronix_30lfxg18ac_read_otp;
>>>> +     mtd->_write_user_prot_reg = macronix_30lfxg18ac_write_otp;
>>>> +     mtd->_lock_user_prot_reg = macronix_30lfxg18ac_lock_otp;
>>>> +}
>>>> +
>>>>  static int macronix_nand_init(struct nand_chip *chip)
>>>>  {
>>>>       if (nand_is_slc(chip))
>>>> @@ -325,6 +540,7 @@ static int macronix_nand_init(struct nand_chip *chip)
>>>>       macronix_nand_onfi_init(chip);
>>>>       macronix_nand_block_protection_support(chip);
>>>>       macronix_nand_deep_power_down_support(chip);
>>>> +     macronix_nand_setup_otp(chip);
>>>>
>>>>       return 0;
>>>>  }  
>>>
>>>
>>> Thanks,
>>> Miquèl  
>>
>> Thanks
>> Jaime
> 
> 



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