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Subject: Re: [External] : RE: [PATCH RESEND v3] mmc-utils: Add eMMC erase
 command support
To:     Avri Altman <Avri.Altman@wdc.com>,
        "luserhker@gmail.com" <luserhker@gmail.com>,
        "beanhuo@micron.com" <beanhuo@micron.com>,
        "kenny.gibbons@oracle.com" <kenny.gibbons@oracle.com>,
        "rkamdar@micron.com" <rkamdar@micron.com>,
        "chris@printf.net" <chris@printf.net>,
        "ulf.hansson@linaro.org" <ulf.hansson@linaro.org>
Cc:     "linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
References: <20210427195157.26568-1-luserhker@gmail.com>
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From:   kimito.sakata@oracle.com
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Date:   Wed, 28 Apr 2021 09:59:13 -0600
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Avri

Thanks. I will respond to you when I get the chance to go through all of it.

Kimito

On 4/27/2021 11:57 PM, Avri Altman wrote:
> Hi Kimito & Bean,
>
>> From: Kimito Sakata <kimito.sakata@oracle.com>
>>
>> we have been using this erase feature for a while, but it is
>> still not merged into the upstream mmc-utils. Especially, for
>> the customer, every time when they update the mmc-utils, they
>> should re-install this patch again, let's try to make this
>> erase command upstreamed in the mmc-utils.
>>
>> We need to send 3 MMC commands and it is important that they
>> stay in sequence. Therefore we are using MMC_IOC_MULTI_CMD.
> You might also want to indicate on which platform it was tested.
>
>> Co-developed-by: Bean Huo <beanhuo@micron.com>
>> Signed-off-by: Bean Huo <beanhuo@micron.com>
>> Signed-off-by: Kimito Sakata <kimito.sakata@oracle.com>
>> Reviewed-by: Kenneth Gibbons <kenny.gibbons@oracle.com>
>>
>> Changelog:
>> v2--v3:
>>      1. Remove redundant ifndef
>>
>> V1--V2:
>>      1. refactor Kimito's original patch
>>      2. change to use MMC_IOC_MULTI_CMD
>>      3. add checkup if eMMC devie supports secure erase/trim
>> ---
>>   mmc.c      |   8 ++++
>>   mmc.h      |  13 +++++-
>>   mmc_cmds.c | 130
>> +++++++++++++++++++++++++++++++++++++++++++++++++++++
>>   mmc_cmds.h |   1 +
>>   4 files changed, 151 insertions(+), 1 deletion(-)
>>
>> diff --git a/mmc.c b/mmc.c
>> index f3d724b..eb2638b 100644
>> --- a/mmc.c
>> +++ b/mmc.c
>> @@ -229,6 +229,14 @@ static struct Command commands[] = {
>>                  "Run Field Firmware Update with <image name> on <device>.\n",
>>            NULL
>>          },
>> +       { do_erase, -4,
>> +       "erase", "<type> " "<start address> " "<end address> " "<device>\n"
>> +               "Send Erase CMD38 with specific argument to the <device>\n\n"
>> +               "NOTE!: This will delete all user data in the specified region of the
>> device\n"
>> +               "<type> must be: legacy | discard | secure-erase | "
>> +               "secure-trim1 | secure-trim2 | trim \n",
>> +       NULL
>> +       },
>>          { 0, 0, 0, 0 }
>>   };
>>
>> diff --git a/mmc.h b/mmc.h
>> index 5754a9d..e9766d7 100644
>> --- a/mmc.h
>> +++ b/mmc.h
>> @@ -35,7 +35,15 @@
>>   #define MMC_SET_WRITE_PROT     28    /* ac   [31:0] data addr   R1b */
>>   #define MMC_CLEAR_WRITE_PROT   29    /* ac   [31:0] data addr   R1b */
>>   #define MMC_SEND_WRITE_PROT_TYPE 31   /* ac   [31:0] data addr   R1  */
>> -
>> +#define MMC_ERASE_GROUP_START  35    /* ac   [31:0] data addr   R1  */
>> +#define MMC_ERASE_GROUP_END    36    /* ac   [31:0] data addr   R1  */
>> +#define MMC_ERASE              38    /* ac   [31] Secure request
>> +                                             [30:16] set to 0
>> +                                             [15] Force Garbage Collect request
>> +                                             [14:2] set to 0
>> +                                             [1] Discard Enable
>> +                                             [0] Identify Write Blocks for
>> +                                             Erase (or TRIM Enable)  R1b */
>>   /*
>>    * EXT_CSD fields
>>    */
>> @@ -62,6 +70,7 @@
>>   #define EXT_CSD_CACHE_SIZE_2           251
>>   #define EXT_CSD_CACHE_SIZE_1           250
>>   #define EXT_CSD_CACHE_SIZE_0           249
>> +#define EXT_CSD_SEC_FEATURE_SUPPORT    231
>>   #define EXT_CSD_BOOT_INFO              228     /* R/W */
>>   #define EXT_CSD_HC_ERASE_GRP_SIZE      224
>>   #define EXT_CSD_HC_WP_GRP_SIZE         221
>> @@ -190,6 +199,8 @@
>>   #define EXT_CSD_REV_V4_2               2
>>   #define EXT_CSD_REV_V4_1               1
>>   #define EXT_CSD_REV_V4_0               0
>> +#define EXT_CSD_SEC_GB_CL_EN           (1<<4)
>> +#define EXT_CSD_SEC_ER_EN              (1<<0)
>>
>>
>>   /* From kernel linux/mmc/core.h */
>> diff --git a/mmc_cmds.c b/mmc_cmds.c
>> index 6c24cea..24f80db 100644
>> --- a/mmc_cmds.c
>> +++ b/mmc_cmds.c
>> @@ -2514,6 +2514,136 @@ int do_cache_dis(int nargs, char **argv)
>>          return do_cache_ctrl(0, nargs, argv);
>>   }
>>
>> +static int erase(int dev_fd, __u32 argin, __u32 start, __u32 end)
>> +{
>> +       int ret = 0;
>> +       struct mmc_ioc_multi_cmd *multi_cmd;
>> +
>> +       multi_cmd = calloc(1, sizeof(struct mmc_ioc_multi_cmd) +
>> +                          3 * sizeof(struct mmc_ioc_cmd));
>> +       if (!multi_cmd) {
>> +               perror("Failed to allocate memory");
>> +               return -ENOMEM;
>> +       }
> I am missing reference to ERASE_GROUP_DEF.
> It affects the timeout, size of erase group etc.
> Don't you need to query for before starting to build the command?
>
>> +
>> +       multi_cmd->num_of_cmds = 3;
>> +       /* Set erase start address */
>> +       multi_cmd->cmds[0].opcode = MMC_ERASE_GROUP_START;
>> +       multi_cmd->cmds[0].arg = start;
>> +       multi_cmd->cmds[0].flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 |
>> MMC_CMD_AC;
>> +       multi_cmd->cmds[0].write_flag = 1;
>> +
>> +       /* Set erase end address */
>> +       multi_cmd->cmds[1].opcode = MMC_ERASE_GROUP_END;
>> +       multi_cmd->cmds[1].arg = end;
>> +       multi_cmd->cmds[1].flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 |
>> MMC_CMD_AC;
>> +       multi_cmd->cmds[1].write_flag = 1;
>> +
>> +       /* Send Erase Command */
>> +       multi_cmd->cmds[2].opcode = MMC_ERASE;
>> +       multi_cmd->cmds[2].arg = argin;
>> +       multi_cmd->cmds[2].cmd_timeout_ms = 300*255*255;
>> +       multi_cmd->cmds[2].flags = MMC_RSP_SPI_R1B | MMC_RSP_R1B |
>> MMC_CMD_AC;
>> +       multi_cmd->cmds[2].write_flag = 1;
>> +
>> +       /* send erase cmd with multi-cmd */
>> +       ret = ioctl(dev_fd, MMC_IOC_MULTI_CMD, multi_cmd);
>> +       if (ret)
>> +               perror("Erase multi-cmd ioctl");
>> +
>> +       free(multi_cmd);
>> +       return ret;
>> +#endif
>> +}
>> +
>> +int do_erase(int nargs, char **argv)
>> +{
>> +       int dev_fd, ret;
>> +       char *print_str;
>> +       char **eptr = NULL;
>> +       __u8 ext_csd[512], checkup_mask = 0;
>> +       __u32 arg, start, end;
>> +
>> +       if (nargs != 5) {
>> +               fprintf(stderr, "Usage: erase <type> <start addr> <end addr>
>> </path/to/mmcblkX>\n");
>> +               exit(1);
>> +       }
>> +
>> +       if (strstr(argv[2], "0x") || strstr(argv[2], "0X"))
>> +               start = strtol(argv[2], eptr, 16);
>> +       else
>> +               start = strtol(argv[2], eptr, 10);
>> +
>> +       if (strstr(argv[3], "0x") || strstr(argv[3], "0X"))
>> +               end = strtol(argv[3], eptr, 16);
>> +       else
>> +               end = strtol(argv[3], eptr, 10);
> You are not really using eptr - maybe just call strtol with NULL?
>
>> +
>> +       if (end < start) {
>> +               fprintf(stderr, "erase start [0x%08x] > erase end [0x%08x]\n",
>> +                       start, end);
>> +               exit(1);
>> +       }
> Start & End are in bytes for media < 2GB, and in sectors for media >=2GB.
> Should also check for legal erase group restrictions.
>
>> +
>> +       if (strcmp(argv[1], "legacy") == 0) {
>> +               arg = 0x00000000;
>> +               print_str = "Legacy Erase";
>> +       } else if (strcmp(argv[1], "discard") == 0) {
>> +               arg = 0x00000003;
>> +               print_str = "Discard";
>> +       } else if (strcmp(argv[1], "secure-erase") == 0) {
>> +               print_str = "Secure Erase";
>> +               checkup_mask = EXT_CSD_SEC_ER_EN;
>> +               arg = 0x80000000;
>> +       } else if (strcmp(argv[1], "secure-trim1") == 0) {
>> +               print_str = "Secure Trim Step 1";
>> +               checkup_mask = EXT_CSD_SEC_ER_EN | EXT_CSD_SEC_GB_CL_EN;
>> +               arg = 0x80000001;
>> +       } else if (strcmp(argv[1], "secure-trim2") == 0) {
>> +               print_str = "Secure Trim Step 2";
>> +               checkup_mask = EXT_CSD_SEC_ER_EN | EXT_CSD_SEC_GB_CL_EN;
>> +               arg = 0x80008000;
>> +       } else if (strcmp(argv[1], "trim") == 0) {
>> +               print_str = "Trim";
>> +               checkup_mask = EXT_CSD_SEC_GB_CL_EN;
>> +               arg = 0x00000001;
>> +       } else {
>> +               fprintf(stderr, "Unknown erase type: %s\n", argv[1]);
>> +               exit(1);
>> +       }
> Maybe use an enum for the erase type to avoid the strcmp?
> Then need to update the usage message.
>
>> +
>> +       dev_fd = open(argv[4], O_RDWR);
>> +       if (dev_fd < 0) {
>> +               perror(argv[4]);
>> +               exit(1);
>> +       }
> How do you differentiate between mmc and SD devices?
> And for SD you should send different commands(35/36 vs. 32/33).
> Do you intend to support SD devices as well? In another patch?
>
>> +
>> +       if (checkup_mask) {
>> +               ret = read_extcsd(dev_fd, ext_csd);
>> +               if (ret) {
>> +                       fprintf(stderr, "Could not read EXT_CSD from %s\n",
>> +                               argv[4]);
>> +                       goto out;
>> +               }
>> +               if ((checkup_mask & ext_csd[EXT_CSD_SEC_FEATURE_SUPPORT]) !=
>> +                                                               checkup_mask) {
>> +                       fprintf(stderr, "%s is not supported in %s\n",
>> +                               print_str, argv[4]);
>> +                       ret = -ENOTSUP;
>> +                       goto out;
>> +               }
> EXT_CSD_SEC_FEATURE_SUPPORT might also contains the sanitize bit,
> as well as reserved bits that you shouldn't assume they are 0, so I am not sure that this condition is correct.
> The checkup only refers to bit 0 and bit 4 - maybe add a helper that accept &args and returns 0 if allowed...
>
>
> Thanks,
> Avri
>
>> +
>> +       }
>> +       printf("Executing %s from 0x%08x to 0x%08x\n", print_str, start, end);
>> +
>> +       ret = erase(dev_fd, arg, start, end);
>> +out:
>> +       printf(" %s %s!\n\n", print_str, ret ? "Failed" : "Succeed");
>> +       close(dev_fd);
>> +       return ret;
>> +}
>> +
>> +
>>   int do_ffu(int nargs, char **argv)
>>   {
>>   #ifndef MMC_IOC_MULTI_CMD
>> diff --git a/mmc_cmds.h b/mmc_cmds.h
>> index 9d3246c..8331ab2 100644
>> --- a/mmc_cmds.h
>> +++ b/mmc_cmds.h
>> @@ -45,3 +45,4 @@ int do_ffu(int nargs, char **argv);
>>   int do_read_scr(int argc, char **argv);
>>   int do_read_cid(int argc, char **argv);
>>   int do_read_csd(int argc, char **argv);
>> +int do_erase(int nargs, char **argv);
>> --
>> 2.24.1 (Apple Git-126)