On Tue, 20 Aug 2024 at 16:47, Ulf Hansson ulf.hansson@linaro.org wrote:
On Wed, 14 Aug 2024 at 17:36, Jens Wiklander jens.wiklander@linaro.org 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 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.
Taking the needed reference to md->disk in mmc_blk_alloc_rpmb_part() instead of in mmc_rpmb_chrdev_open(). This is needed by the route_frames() function pointer in struct rpmb_ops.
Signed-off-by: Tomas Winkler tomas.winkler@intel.com Signed-off-by: Alexander Usyskin alexander.usyskin@intel.com Signed-off-by: Jens Wiklander jens.wiklander@linaro.org Tested-by: Manuel Traut manut@mecka.net Reviewed-by: Linus Walleij linus.walleij@linaro.org
First of all, sorry for the long delay! Besides only one comment, see more below, this looks good to me.
drivers/mmc/core/block.c | 242 ++++++++++++++++++++++++++++++++++++++- 1 file changed, 240 insertions(+), 2 deletions(-)
diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c index 2c9963248fcb..cc7318089cf2 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> @@ -76,6 +78,48 @@ MODULE_ALIAS("mmc:block"); #define MMC_EXTRACT_INDEX_FROM_ARG(x) ((x & 0x00FF0000) >> 16) #define MMC_EXTRACT_VALUE_FROM_ARG(x) ((x & 0x0000FF00) >> 8)
+/**
- struct rpmb_frame - rpmb frame as defined by eMMC 5.1 (JESD84-B51)
- @stuff : stuff bytes
- @key_mac : The authentication key or the message authentication
code (MAC) depending on the request/response type.
The MAC will be delivered in the last (or the only)
block of data.
- @data : Data to be written or read by signed access.
- @nonce : Random number generated by the host for the requests
and copied to the response by the RPMB engine.
- @write_counter: Counter value for the total amount of the successful
authenticated data write requests made by the host.
- @addr : Address of the data to be programmed to or read
from the RPMB. Address is the serial number of
the accessed block (half sector 256B).
- @block_count : Number of blocks (half sectors, 256B) requested to be
read/programmed.
- @result : Includes information about the status of the write counter
(valid, expired) and result of the access made to the RPMB.
- @req_resp : Defines the type of request and response to/from the memory.
- The stuff bytes and big-endian properties are modeled to fit to the spec.
- */
+struct rpmb_frame {
u8 stuff[196];u8 key_mac[32];u8 data[256];u8 nonce[16];__be32 write_counter;__be16 addr;__be16 block_count;__be16 result;__be16 req_resp;+} __packed;
+#define RPMB_PROGRAM_KEY 0x1 /* Program RPMB Authentication Key */ +#define RPMB_GET_WRITE_COUNTER 0x2 /* Read RPMB write counter */ +#define RPMB_WRITE_DATA 0x3 /* Write data to RPMB partition */ +#define RPMB_READ_DATA 0x4 /* Read data from RPMB partition */ +#define RPMB_RESULT_READ 0x5 /* Read result request (Internal) */
static DEFINE_MUTEX(block_mutex);
/* @@ -155,6 +199,7 @@ static const struct bus_type mmc_rpmb_bus_type = {
- @id: unique device ID number
- @part_index: partition index (0 on first)
- @md: parent MMC block device
*/
- @rdev: registered RPMB device
- @node: list item, so we can put this device on a list
struct mmc_rpmb_data { @@ -163,6 +208,7 @@ struct mmc_rpmb_data { int id; unsigned int part_index; struct mmc_blk_data *md;
struct rpmb_dev *rdev; struct list_head node;};
@@ -2670,7 +2716,6 @@ static int mmc_rpmb_chrdev_open(struct inode *inode, struct file *filp)
get_device(&rpmb->dev); filp->private_data = rpmb;
mmc_blk_get(rpmb->md->disk);If I understand correctly, the call to mmc_blk_get() is here to reference count the usage of the md->disk. So when a user decides to open the chrdev, we are keeping a reference to the corresponding data around, until the corresponding file descriptor is closed and mmc_rpmb_chrdev_release() is called. We do the similar thing if the regular mmc block device is opened.
If we change to increase/decrease the reference count from mmc_blk_alloc_rpmb_part()/mmc_blk_rpmb_device_release() instead - are you certain that we are still taking care of the above scenario correctly?
I guess a test that opens the chrdev and then unbinding the mmc host driver should tell us. :-)
From your nice little debugging session conveyed to me offlist, you have convinced me that this is perfectly okay.
Therefore, please add:
Reviewed-by: Ulf Hansson ulf.hansson@linaro.org
Kind regards Uffe