[PATCH 3/9] mci: detect RPMB partitions

[Sascha Hauer <s.hauer@pengutronix.de>]

Detect RPMB partitions and initialize a struct mci_part for them. We do
not actually register the RPMB partitions as we can't access them with
regular mci_do_block_op() and we would only access encrypted data anyway.

Right now we assume that only one RPMB is present in a system which
covers the 99% case. Should there be multiple RPMBs found we issue a
warning message as there is no way to specify which one shall be used,
the first one found will be used which may vary depending on probe
order.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 drivers/mci/mci-core.c | 36 ++++++++++++++++++++++++++++++++++++
 include/mci.h          |  7 ++++++-
 2 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/drivers/mci/mci-core.c b/drivers/mci/mci-core.c
index b7ea0df3cb..18c910c4c3 100644
--- a/drivers/mci/mci-core.c
+++ b/drivers/mci/mci-core.c
@@ -647,6 +647,15 @@ static blkcnt_t mci_calc_blk_cnt(blkcnt_t cap, unsigned shift)
 	return ret;
 }
 
+/*
+ * We currently only support a single RPMB partition. Most systems only have a
+ * single eMMC and thus only one RPMB partition, so we are fine on most systems.
+ * When multiple RPMB partitions are found we issue a warning message as the
+ * first RPMB found will be used. There currently is no way to specify which one
+ * shall be used.
+ */
+static struct mci_part *rpmb_partition;
+
 static void mci_part_add(struct mci *mci, uint64_t size,
                         unsigned int part_cfg, char *name, char *partname, int idx, bool ro,
                         int area_type)
@@ -671,6 +680,16 @@ static void mci_part_add(struct mci *mci, uint64_t size,
 	part->part_cfg = part_cfg;
 	part->idx = idx;
 
+	if (area_type == MMC_BLK_DATA_AREA_RPMB) {
+		mci->rpmb_part = part;
+		if (rpmb_partition) {
+			dev_warn(&mci->dev, "Multiple RPMB partitions found. Only %s will be used\n",
+				 rpmb_partition->mci->host->devname);
+		} else {
+			rpmb_partition = mci->rpmb_part;
+		}
+	}
+
 	if (area_type == MMC_BLK_DATA_AREA_MAIN) {
 		cdev_set_of_node(&part->blk.cdev, mci->host->hw_dev->of_node);
 		part->blk.cdev.flags |= DEVFS_IS_MCI_MAIN_PART_DEV;
@@ -822,6 +841,20 @@ static int mmc_change_freq(struct mci *mci)
 		mci->boot_ack_enable = (mci->ext_csd_part_config >> 6) & 0x1;
 	}
 
+	if (mci->ext_csd[EXT_CSD_REV] >= 5) {
+		if (mci->ext_csd[EXT_CSD_RPMB_SIZE_MULT]) {
+			char *name, *partname;
+
+			partname = basprintf("rpmb");
+			name = basprintf("%s.%s", mci->cdevname, partname);
+
+			mci_part_add(mci, mci->ext_csd[EXT_CSD_RPMB_SIZE_MULT] << 17,
+				EXT_CSD_PART_CONFIG_ACC_RPMB,
+				name, partname, 0, false,
+				MMC_BLK_DATA_AREA_RPMB);
+		}
+	}
+
 	if (IS_ENABLED(CONFIG_MCI_MMC_GPP_PARTITIONS))
 		mmc_extract_gpp_partitions(mci);
 
@@ -2601,6 +2634,9 @@ static int mci_register_partition(struct mci_part *part)
 	part->blk.ops = &mci_ops;
 	part->blk.type = IS_SD(mci) ? BLK_TYPE_SD : BLK_TYPE_MMC;
 
+	if (part->area_type == MMC_BLK_DATA_AREA_RPMB)
+		return 0;
+
 	rc = blockdevice_register(&part->blk);
 	if (rc != 0) {
 		dev_err(&mci->dev, "Failed to register MCI/SD blockdevice\n");
diff --git a/include/mci.h b/include/mci.h
index 8084df813a..08a3e46f7d 100644
--- a/include/mci.h
+++ b/include/mci.h
@@ -347,6 +347,7 @@
  */
 #define EXT_CSD_PART_CONFIG_ACC_MASK	(0x7)
 #define EXT_CSD_PART_CONFIG_ACC_BOOT0	(0x1)
+#define EXT_CSD_PART_CONFIG_ACC_RPMB	(0x3)
 #define EXT_CSD_PART_CONFIG_ACC_GPP0	(0x4)
 
 #define EXT_CSD_CMD_SET_NORMAL		(1<<0)
@@ -606,9 +607,11 @@ struct mci_host {
 #define MMC_NUM_BOOT_PARTITION	2
 #define MMC_NUM_GP_PARTITION	4
 #define MMC_NUM_USER_PARTITION	1
+#define MMC_NUM_RPMB_PARTITION	1
 #define MMC_NUM_PHY_PARTITION	(MMC_NUM_BOOT_PARTITION + \
                                  MMC_NUM_GP_PARTITION + \
-                                 MMC_NUM_USER_PARTITION)
+                                 MMC_NUM_USER_PARTITION + \
+                                 MMC_NUM_RPMB_PARTITION)
 
 struct mci_part {
 	struct block_device	blk;		/**< the blockdevice for the card */
@@ -674,6 +677,8 @@ struct mci {
 	int boot_ack_enable;
 
 	struct mci_part part[MMC_NUM_PHY_PARTITION];
+	struct mci_part *rpmb_part;
+
 	int nr_parts;
 	char *cdevname;
 

-- 
2.39.5