Re: [PATCH v2 2/3] mmc: block: register RPMB partition with the RPMB subsystem

[Jens Wiklander]

On Thu, Feb 1, 2024 at 10:18 AM Jorge Ramirez-Ortiz, Foundries
<jorge@xxxxxxxxxxxx> wrote:
>
> On 31/01/24 18:43:46, Jens Wiklander wrote:
> > Register eMMC RPMB partition with the RPMB subsystem and provide
> > an implementation for the RPMB access operations abstracting
> > the actual multi step process.
> >
> > Add callbacks for getting and putting the needed resources, that is, the
> > RPMB data and the RPMB disk.
> >
> > Add a callback to extract the needed device information at registration
> > to avoid accessing the struct mmc_card at a later stage as we're not
> > holding a reference counter for this struct.
> >
> > Signed-off-by: Tomas Winkler <tomas.winkler@xxxxxxxxx>
> > Signed-off-by: Alexander Usyskin <alexander.usyskin@xxxxxxxxx>
> > Signed-off-by: Jens Wiklander <jens.wiklander@xxxxxxxxxx>
> > ---
> >  drivers/mmc/core/block.c | 177 +++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 177 insertions(+)
> >
> > diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
> > index 32d49100dff5..5286e0b3a5a2 100644
> > --- a/drivers/mmc/core/block.c
> > +++ b/drivers/mmc/core/block.c
> > @@ -33,6 +33,7 @@
> >  #include <linux/cdev.h>
> >  #include <linux/mutex.h>
> >  #include <linux/scatterlist.h>
> > +#include <linux/string.h>
> >  #include <linux/string_helpers.h>
> >  #include <linux/delay.h>
> >  #include <linux/capability.h>
> > @@ -40,6 +41,7 @@
> >  #include <linux/pm_runtime.h>
> >  #include <linux/idr.h>
> >  #include <linux/debugfs.h>
> > +#include <linux/rpmb.h>
> >
> >  #include <linux/mmc/ioctl.h>
> >  #include <linux/mmc/card.h>
> > @@ -163,6 +165,7 @@ struct mmc_rpmb_data {
> >       int id;
> >       unsigned int part_index;
> >       struct mmc_blk_data *md;
> > +     struct rpmb_dev *rdev;
> >       struct list_head node;
> >  };
> >
> > @@ -2707,6 +2710,169 @@ static void mmc_blk_rpmb_device_release(struct device *dev)
> >       kfree(rpmb);
> >  }
> >
> > +static void rpmb_op_mmc_get_resources(struct device *dev)
> > +{
> > +     struct mmc_rpmb_data *rpmb = dev_get_drvdata(dev);
> > +
> > +     /*
> > +      * When the MMC card is removed rpmb_dev_unregister() is called
> > +      * from mmc_blk_remove_rpmb_part(). That removes references to the
> > +      * devices in struct mmc_rpmb_data and rpmb->md. Since struct
> > +      * rpmb_dev can still reach those structs we must hold a reference
> > +      * until struct rpmb_dev also is released.
> > +      *
> > +      * This is analogous to what's done in mmc_rpmb_chrdev_open() and
> > +      * mmc_rpmb_chrdev_release() below.
> > +      */
> > +     get_device(dev);
> > +     mmc_blk_get(rpmb->md->disk);
> > +}
> > +
> > +static void rpmb_op_mmc_put_resources(struct device *dev)
> > +{
> > +     struct mmc_rpmb_data *rpmb = dev_get_drvdata(dev);
> > +
> > +     mmc_blk_put(rpmb->md);
> > +     put_device(dev);
> > +}
> > +
> > +static struct mmc_blk_ioc_data **alloc_idata(struct mmc_rpmb_data *rpmb,
> > +                                          unsigned int cmd_count)
> > +{
> > +     struct mmc_blk_ioc_data **idata;
> > +     unsigned int n;
> > +
> > +     idata = kcalloc(cmd_count, sizeof(*idata), GFP_KERNEL);
> > +     if (!idata)
> > +             return NULL;
> > +
> > +     for (n = 0; n < cmd_count; n++) {
> > +             idata[n] = kcalloc(1, sizeof(**idata), GFP_KERNEL);
> > +             if (!idata[n]) {
> > +                     kfree(idata);
>
> don't you need to unwind these allocations on error?
>

Yes, you're right.

Thanks,
Jens

> > +                     return NULL;
> > +             }
> > +             idata[n]->rpmb = rpmb;
> > +     }
> > +
> > +     return idata;
> > +}
> > +
> > +static void set_idata(struct mmc_blk_ioc_data *idata, u32 opcode,
> > +                   int write_flag, u8 *buf, unsigned int buf_bytes)
> > +{
> > +     idata->ic.opcode = opcode;
> > +     idata->ic.flags = MMC_RSP_R1 | MMC_CMD_ADTC;
> > +     idata->ic.write_flag = write_flag;
> > +     idata->ic.blksz = sizeof(struct rpmb_frame);
> > +     idata->ic.blocks = buf_bytes /  idata->ic.blksz;
> > +     idata->buf = buf;
> > +     idata->buf_bytes = buf_bytes;
> > +}
> > +
> > +static void free_idata(struct mmc_blk_ioc_data **idata, unsigned int cmd_count)
> > +{
> > +     unsigned int n;
> > +
> > +     for (n = 0; n < cmd_count; n++)
> > +             kfree(idata[n]);
> > +     kfree(idata);
> > +}
> > +
> > +static int rpmb_op_mmc_route_frames(struct device *dev, bool write, u8 *req,
> > +                                 unsigned int req_len, u8 *resp,
> > +                                 unsigned int resp_len)
> > +{
> > +     struct mmc_rpmb_data *rpmb = dev_get_drvdata(dev);
> > +     struct mmc_blk_data *md = rpmb->md;
> > +     struct mmc_blk_ioc_data **idata;
> > +     unsigned int cmd_count;
> > +     struct request *rq;
> > +     int ret;
> > +
> > +     if (write)
> > +             cmd_count = 3;
> > +     else
> > +             cmd_count = 2;
> > +
> > +     if (IS_ERR(md->queue.card))
> > +             return PTR_ERR(md->queue.card);
> > +
> > +     idata = alloc_idata(rpmb, cmd_count);
> > +     if (!idata)
> > +             return -ENOMEM;
> > +
> > +     if (write) {
> > +             struct rpmb_frame *frm = (struct rpmb_frame *)resp;
> > +
> > +             /* Send write request frame(s) */
> > +             set_idata(idata[0], MMC_WRITE_MULTIPLE_BLOCK,
> > +                       1 | MMC_CMD23_ARG_REL_WR, req, req_len);
> > +
> > +             /* Send result request frame */
> > +             memset(frm, 0, sizeof(*frm));
> > +             frm->req_resp = cpu_to_be16(RPMB_RESULT_READ);
> > +             set_idata(idata[1], MMC_WRITE_MULTIPLE_BLOCK, 1, resp,
> > +                       resp_len);
> > +
> > +             /* Read response frame */
> > +             set_idata(idata[2], MMC_READ_MULTIPLE_BLOCK, 0, resp, resp_len);
> > +     } else {
> > +             /* Send write request frame(s) */
> > +             set_idata(idata[0], MMC_WRITE_MULTIPLE_BLOCK, 1, req, req_len);
> > +
> > +             /* Read response frame */
> > +             set_idata(idata[1], MMC_READ_MULTIPLE_BLOCK, 0, resp, resp_len);
> > +     }
> > +
> > +     rq = blk_mq_alloc_request(md->queue.queue, REQ_OP_DRV_OUT, 0);
> > +     if (IS_ERR(rq)) {
> > +             ret = PTR_ERR(rq);
> > +             goto out;
> > +     }
> > +
> > +     req_to_mmc_queue_req(rq)->drv_op = MMC_DRV_OP_IOCTL_RPMB;
> > +     req_to_mmc_queue_req(rq)->drv_op_result = -EIO;
> > +     req_to_mmc_queue_req(rq)->drv_op_data = idata;
> > +     req_to_mmc_queue_req(rq)->ioc_count = cmd_count;
> > +     blk_execute_rq(rq, false);
> > +     ret = req_to_mmc_queue_req(rq)->drv_op_result;
> > +
> > +     blk_mq_free_request(rq);
> > +
> > +out:
> > +     free_idata(idata, cmd_count);
> > +     return ret;
> > +}
> > +
> > +static int rpmb_op_mmc_set_dev_info(struct device *dev, struct rpmb_dev *rdev)
> > +{
> > +     struct mmc_rpmb_data *rpmb = dev_get_drvdata(dev);
> > +     struct mmc_card *card = rpmb->md->queue.card;
> > +     unsigned int n;
> > +     u32 cid[4];
> > +
> > +     for (n = 0; n < 4; n++)
> > +             cid[n] = be32_to_cpu(card->raw_cid[n]);
> > +
> > +     rdev->dev_id = kmemdup(cid, sizeof(cid), GFP_KERNEL);
> > +     if (!rdev->dev_id)
> > +             return -ENOMEM;
> > +     rdev->dev_id_len = sizeof(cid);
> > +     rdev->reliable_wr_count = card->ext_csd.raw_rpmb_size_mult;
> > +     rdev->capacity = card->ext_csd.rel_sectors;
> > +
> > +     return 0;
> > +}
> > +
> > +static struct rpmb_ops rpmb_mmc_ops = {
> > +     .type = RPMB_TYPE_EMMC,
> > +     .get_resources = rpmb_op_mmc_get_resources,
> > +     .put_resources = rpmb_op_mmc_put_resources,
> > +     .route_frames = rpmb_op_mmc_route_frames,
> > +     .set_dev_info = rpmb_op_mmc_set_dev_info,
> > +};
> > +
> >  static int mmc_blk_alloc_rpmb_part(struct mmc_card *card,
> >                                  struct mmc_blk_data *md,
> >                                  unsigned int part_index,
> > @@ -2751,6 +2917,14 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card,
> >               goto out_put_device;
> >       }
> >
> > +     rpmb->rdev = rpmb_dev_register(&rpmb->dev, &rpmb_mmc_ops);
> > +     if (IS_ERR(rpmb->rdev)) {
> > +             pr_err("%s: could not register RPMB device\n", rpmb_name);
> > +             ret = PTR_ERR(rpmb->rdev);
> > +             rpmb->rdev = NULL;
> > +             goto out_cdev_device_del;
> > +     }
> > +
> >       list_add(&rpmb->node, &md->rpmbs);
> >
> >       string_get_size((u64)size, 512, STRING_UNITS_2,
> > @@ -2762,6 +2936,8 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card,
> >
> >       return 0;
> >
> > +out_cdev_device_del:
> > +     cdev_device_del(&rpmb->chrdev, &rpmb->dev);
> >  out_put_device:
> >       put_device(&rpmb->dev);
> >       return ret;
> > @@ -2770,6 +2946,7 @@ static int mmc_blk_alloc_rpmb_part(struct mmc_card *card,
> >  static void mmc_blk_remove_rpmb_part(struct mmc_rpmb_data *rpmb)
> >
> >  {
> > +     rpmb_dev_unregister(rpmb->rdev);
> >       cdev_device_del(&rpmb->chrdev, &rpmb->dev);
> >       put_device(&rpmb->dev);
> >  }
> > --
> > 2.34.1
> >