Re: [PATCH resend] mmc: Added ioctl to let userspace apps send ACMDs

[Ben Dooks <ben@trinity.fluff.org>]

On Thu, Mar 17, 2011 at 11:28:55AM -0700, John Calixto wrote:
> Part 3 of the SD Specification (SD Card Association; www.sdcard.org) describes
> how to use the security function of an SD card using application specific
> commands in conjunction with CPRM algorithms and keys licensed from the 4C
> Entity (www.4centity.com).  This allows userspace applications to access this
> security feature.
> 
> Tested on TI PCIxx12 (SDHCI), Sigma Designs SMP8652 SoC, TI OMAP3621 SoC, TI
> OMAP3630 SoC, Samsung S5PC110 SoC, Qualcomm MSM7200A SoC.
> 
> Signed-off-by: John Calixto <john.calixto@modsystems.com>
> ---
> (I'm resending because I forgot to cc the maintainer - sorry!)
> 
>  drivers/mmc/card/block.c  |  149 +++++++++++++++++++++++++++++++++++++++++++++
>  drivers/mmc/core/sd_ops.c |    3 +-
>  include/linux/mmc/core.h  |    1 +
>  include/linux/mmc/sd.h    |   18 ++++++
>  4 files changed, 170 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
> index bfc8a8a..62f742d 100644
> --- a/drivers/mmc/card/block.c
> +++ b/drivers/mmc/card/block.c
> @@ -39,6 +39,7 @@
> 
>  #include <asm/system.h>
>  #include <asm/uaccess.h>
> +#include <asm/delay.h>
> 
>  #include "queue.h"
> 
> @@ -158,11 +159,159 @@ mmc_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo)
>         return 0;
>  }
> 
> +static int mmc_blk_ioctl(struct block_device *bdev, fmode_t mode, unsigned int ioc_cmd, unsigned long ioc_arg)
> +{
> +       struct sd_ioc_cmd sdic = {0};
> +       struct mmc_blk_data *md = NULL;
> +       struct mmc_host *host = NULL;
> +       struct mmc_card *card = NULL;
> +       struct mmc_command cmd = {0};
> +       struct mmc_data data = {0};
> +       int err = 0;
> +       struct mmc_request mrq = {0};
> +       struct scatterlist sg = {0};
> +       unsigned char *blocks = NULL;
> +       size_t data_bytes = 0;
> +#ifdef CONFIG_MMC_DEBUG
> +       char dbgbuf[64] = {0};
> +#endif
> +
> +       /*
> +        * This is primarily used for application specific commands (ACMD), so
> +        * the current ioc_cmd validation is trivial.
> +        */
> +       if (ioc_cmd != SD_IOC_ACMD)
> +               return -EINVAL;
> +
> +       if (copy_from_user(&sdic, (void __user *) ioc_arg, sizeof(struct sd_ioc_cmd))) {
> +               printk(KERN_ERR "%s: error reading ioctl arg from userspace\n", __func__);
> +               return -EFAULT;
> +       }
> +
> +       if (sdic.struct_version != SD_IOC_CMD_STRUCT_VERSION)
> +               return -EINVAL;
> +
> +       /* Find the mmc structures based on the bdev. */
> +       md = mmc_blk_get(bdev->bd_disk);
> +       if (!md)
> +               return -EINVAL;
> +
> +       card = md->queue.card;
> +#ifdef CONFIG_MMC_DEBUG
> +       printk(KERN_DEBUG "%s: card = %p\n", __func__, card);
> +#endif
> +       if (IS_ERR(card))
> +               return PTR_ERR(card);
> +
> +#ifdef CONFIG_MMC_DEBUG
> +       printk(KERN_DEBUG "%s: host = %p\n", __func__, card->host);
> +#endif
> +       host = card->host;
> +       BUG_ON(!host);
> +
> +       mmc_claim_host(host);
> +
> +       err = mmc_app_cmd(host, card);
> +       if (err) {
> +               dev_err(mmc_dev(host), "%s: CMD%d error\n", __func__, MMC_APP_CMD);
> +               goto ioctl_done;
> +       }
> +
> +       mrq.cmd = &cmd;
> +       mrq.data = &data;
> +
> +       cmd.opcode = sdic.opcode;
> +       cmd.arg = sdic.arg;
> +       cmd.flags = sdic.flags;
> +
> +       data.sg = &sg;
> +       data.sg_len = 1;
> +       data.blksz = sdic.blksz;
> +       data.blocks = sdic.blocks;
> +
> +       data_bytes = data.blksz * data.blocks;
> +       blocks = (unsigned char *) kzalloc(data_bytes, GFP_KERNEL);

you shouldn't need this cast, 'void *' will go hapilly to any other type.

> +       if (!blocks) {
> +               err = -ENOMEM;
> +               goto ioctl_done;
> +       }
> +       sg_init_one(data.sg, blocks, data_bytes);
> +
> +
> +       if (copy_from_user(blocks, sdic.data, data_bytes)) {
> +               dev_err(mmc_dev(host), "%s: error reading userspace buffer\n", __func__);
> +               err = -EFAULT;
> +               goto ioctl_done;
> +       }
> +       if (sdic.write_flag) {
> +               data.flags = MMC_DATA_WRITE;
> +       } else {
> +               data.flags = MMC_DATA_READ;
> +       }
> +
> +       /* data.flags must already be set before doing this. */
> +       mmc_set_data_timeout(&data, card);
> +       /* Allow overriding the timeout_ns for empirical tuning. */
> +       if (sdic.force_timeout_ns)
> +               data.timeout_ns = sdic.force_timeout_ns;
> +
> +#ifdef CONFIG_MMC_DEBUG
> +       hex_dump_to_buffer(blocks, data_bytes, 16, 1, dbgbuf, sizeof(dbgbuf), 0);
> +       dev_dbg(mmc_dev(host), "%s: first bytes of pre data\n%s\n", __func__, dbgbuf);
> +#endif
> +
> +       mmc_wait_for_req(host, &mrq);
> +
> +       if (cmd.error) {
> +               dev_err(mmc_dev(host), "%s: cmd error %d\n", __func__, cmd.error);
> +               err = cmd.error;
> +               goto ioctl_done;
> +       }
> +       if (data.error) {
> +               dev_err(mmc_dev(host), "%s: data error %d\n", __func__, data.error);
> +               err = data.error;
> +               goto ioctl_done;
> +       }
> +
> +       /*
> +        * According to the SD specs, some commands require a delay after
> +        * issuing the command.
> +        */
> +       if (sdic.postsleep_us)
> +               udelay(sdic.postsleep_us);
> +
> +       if (copy_to_user(&(((struct sd_ioc_cmd *) ioc_arg)->response), cmd.resp, sizeof(u32) * 4)) {
> +               dev_err(mmc_dev(host), "%s: error copying response\n", __func__);
> +               err = -EFAULT;
> +               goto ioctl_done;
> +       }
> +
> +#ifdef CONFIG_MMC_DEBUG
> +       hex_dump_to_buffer(blocks, data_bytes, 16, 1, dbgbuf, sizeof(dbgbuf), 0);
> +       dev_dbg(mmc_dev(host), "%s: first bytes of post data\n%s\n", __func__, dbgbuf);
> +#endif
> +       if (!sdic.write_flag) {
> +               if (copy_to_user(sdic.data, blocks, data_bytes)) {
> +                       dev_err(mmc_dev(host), "%s: error copying data\n", __func__);
> +                       err = -EFAULT;
> +                       goto ioctl_done;
> +               }
> +       }
> +
> +ioctl_done:
> +       if (blocks)
> +               kfree(blocks);
> +       mmc_release_host(host);
> +       mmc_blk_put(md);
> +       return err;
> +}
> +
>  static const struct block_device_operations mmc_bdops = {
>         .open                   = mmc_blk_open,
>         .release                = mmc_blk_release,
>         .getgeo                 = mmc_blk_getgeo,
>         .owner                  = THIS_MODULE,
> +       .ioctl                  = mmc_blk_ioctl,
>  };
> 
>  struct mmc_blk_request {
> diff --git a/drivers/mmc/core/sd_ops.c b/drivers/mmc/core/sd_ops.c
> index 797cdb5..0453dcd 100644
> --- a/drivers/mmc/core/sd_ops.c
> +++ b/drivers/mmc/core/sd_ops.c
> @@ -20,7 +20,7 @@
>  #include "core.h"
>  #include "sd_ops.h"
> 
> -static int mmc_app_cmd(struct mmc_host *host, struct mmc_card *card)
> +int mmc_app_cmd(struct mmc_host *host, struct mmc_card *card)
>  {
>         int err;
>         struct mmc_command cmd;
> @@ -48,6 +48,7 @@ static int mmc_app_cmd(struct mmc_host *host, struct mmc_card *card)
> 
>         return 0;
>  }
> +EXPORT_SYMBOL(mmc_app_cmd);
> 
>  /**
>   *     mmc_wait_for_app_cmd - start an application command and wait for
> diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
> index 64e013f..1adda405 100644
> --- a/include/linux/mmc/core.h
> +++ b/include/linux/mmc/core.h
> @@ -133,6 +133,7 @@ struct mmc_card;
> 
>  extern void mmc_wait_for_req(struct mmc_host *, struct mmc_request *);
>  extern int mmc_wait_for_cmd(struct mmc_host *, struct mmc_command *, int);
> +extern int mmc_app_cmd(struct mmc_host *, struct mmc_card *);
>  extern int mmc_wait_for_app_cmd(struct mmc_host *, struct mmc_card *,
>         struct mmc_command *, int);
> 
> diff --git a/include/linux/mmc/sd.h b/include/linux/mmc/sd.h
> index 3fd85e0..a031cba 100644
> --- a/include/linux/mmc/sd.h
> +++ b/include/linux/mmc/sd.h
> @@ -12,6 +12,8 @@
>  #ifndef MMC_SD_H
>  #define MMC_SD_H
> 
> +#include <linux/ioctl.h>
> +
>  /* SD commands                           type  argument     response */
>    /* class 0 */
>  /* This is basically the same command as for MMC with some quirks. */
> @@ -84,5 +86,21 @@
>  #define SD_SWITCH_ACCESS_DEF   0
>  #define SD_SWITCH_ACCESS_HS    1
> 
> +struct sd_ioc_cmd {
> +    unsigned int struct_version;
> +#define SD_IOC_CMD_STRUCT_VERSION 0
> +    int write_flag;  /* implies direction of data.  true = write, false = read */
> +    unsigned int opcode;
> +    unsigned int arg;
> +    unsigned int flags;
> +    unsigned int postsleep_us;  /* apply usecond delay *after* issuing command */
> +    unsigned int force_timeout_ns;  /* force timeout to be force_timeout_ns ns */
> +    unsigned int response[4];  /* CMD response */
> +    unsigned int blksz;
> +    unsigned int blocks;
> +    unsigned char *data;  /* DAT buffer */
> +};
> +#define SD_IOC_ACMD _IOWR(MMC_BLOCK_MAJOR, 0, struct sd_ioc_cmd *)
> +
>  #endif
> 
> --
> 1.7.4.1
> 
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-- 
Ben Dooks, ben@fluff.org, http://www.fluff.org/ben/

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