mmc: block: register RPMB partition with the RPMB subsystem

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 <[e-mail]>
Signed-off-by: Alexander Usyskin <[e-mail]>
Signed-off-by: Jens Wiklander <[e-mail]>
Tested-by: Manuel Traut <[e-mail]>
Reviewed-by: Linus Walleij <[e-mail]>
Reviewed-by: Ulf Hansson <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Ulf Hansson <[e-mail]>

drivers/mmc/core/block.c

···
 #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>
···
 #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>
···
 #define MMC_BLK_TIMEOUT_MS  (10 * 1000)
 #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);
 
···
  * @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 {
···
 	int id;
 	unsigned int part_index;
 	struct mmc_blk_data *md;
+	struct rpmb_dev *rdev;
 	struct list_head node;
 };
 
···
 
 	get_device(&rpmb->dev);
 	filp->private_data = rpmb;
-	mmc_blk_get(rpmb->md->disk);
 
 	return nonseekable_open(inode, filp);
 }
···
 	struct mmc_rpmb_data *rpmb = container_of(inode->i_cdev,
 						  struct mmc_rpmb_data, chrdev);
 
-	mmc_blk_put(rpmb->md);
 	put_device(&rpmb->dev);
 
 	return 0;
···
 {
 	struct mmc_rpmb_data *rpmb = dev_get_drvdata(dev);
 
+	rpmb_dev_unregister(rpmb->rdev);
+	mmc_blk_put(rpmb->md);
 	ida_free(&mmc_rpmb_ida, rpmb->id);
 	kfree(rpmb);
+}
+
+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 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]) {
+			free_idata(idata, n);
+			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)
+{
+	/*
+	 * The size of an RPMB frame must match what's expected by the
+	 * hardware.
+	 */
+	BUILD_BUG_ON(sizeof(struct rpmb_frame) != 512);
+
+	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 int mmc_route_rpmb_frames(struct device *dev, u8 *req,
+				 unsigned int req_len, u8 *resp,
+				 unsigned int resp_len)
+{
+	struct rpmb_frame *frm = (struct rpmb_frame *)req;
+	struct mmc_rpmb_data *rpmb = dev_get_drvdata(dev);
+	struct mmc_blk_data *md = rpmb->md;
+	struct mmc_blk_ioc_data **idata;
+	struct mmc_queue_req *mq_rq;
+	unsigned int cmd_count;
+	struct request *rq;
+	u16 req_type;
+	bool write;
+	int ret;
+
+	if (IS_ERR(md->queue.card))
+		return PTR_ERR(md->queue.card);
+
+	if (req_len < sizeof(*frm))
+		return -EINVAL;
+
+	req_type = be16_to_cpu(frm->req_resp);
+	switch (req_type) {
+	case RPMB_PROGRAM_KEY:
+		if (req_len != sizeof(struct rpmb_frame) ||
+		    resp_len != sizeof(struct rpmb_frame))
+			return -EINVAL;
+		write = true;
+		break;
+	case RPMB_GET_WRITE_COUNTER:
+		if (req_len != sizeof(struct rpmb_frame) ||
+		    resp_len != sizeof(struct rpmb_frame))
+			return -EINVAL;
+		write = false;
+		break;
+	case RPMB_WRITE_DATA:
+		if (req_len % sizeof(struct rpmb_frame) ||
+		    resp_len != sizeof(struct rpmb_frame))
+			return -EINVAL;
+		write = true;
+		break;
+	case RPMB_READ_DATA:
+		if (req_len != sizeof(struct rpmb_frame) ||
+		    resp_len % sizeof(struct rpmb_frame))
+			return -EINVAL;
+		write = false;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (write)
+		cmd_count = 3;
+	else
+		cmd_count = 2;
+
+	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;
+	}
+
+	mq_rq = req_to_mmc_queue_req(rq);
+	mq_rq->drv_op = MMC_DRV_OP_IOCTL_RPMB;
+	mq_rq->drv_op_result = -EIO;
+	mq_rq->drv_op_data = idata;
+	mq_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 mmc_blk_alloc_rpmb_part(struct mmc_card *card,
···
 	rpmb->dev.release = mmc_blk_rpmb_device_release;
 	device_initialize(&rpmb->dev);
 	dev_set_drvdata(&rpmb->dev, rpmb);
+	mmc_blk_get(md->disk);
 	rpmb->md = md;
 
 	cdev_init(&rpmb->chrdev, &mmc_rpmb_fileops);
···
 
 #endif /* CONFIG_DEBUG_FS */
 
+static void mmc_blk_rpmb_add(struct mmc_card *card)
+{
+	struct mmc_blk_data *md = dev_get_drvdata(&card->dev);
+	struct mmc_rpmb_data *rpmb;
+	struct rpmb_dev *rdev;
+	unsigned int n;
+	u32 cid[4];
+	struct rpmb_descr descr = {
+		.type = RPMB_TYPE_EMMC,
+		.route_frames = mmc_route_rpmb_frames,
+		.reliable_wr_count = card->ext_csd.enhanced_rpmb_supported ?
+				     2 : 32,
+		.capacity = card->ext_csd.raw_rpmb_size_mult,
+		.dev_id = (void *)cid,
+		.dev_id_len = sizeof(cid),
+	};
+
+	/*
+	 * Provice CID as an octet array. The CID needs to be interpreted
+	 * when used as input to derive the RPMB key since some fields
+	 * will change due to firmware updates.
+	 */
+	for (n = 0; n < 4; n++)
+		cid[n] = be32_to_cpu((__force __be32)card->raw_cid[n]);
+
+	list_for_each_entry(rpmb, &md->rpmbs, node) {
+		rdev = rpmb_dev_register(&rpmb->dev, &descr);
+		if (IS_ERR(rdev)) {
+			pr_warn("%s: could not register RPMB device\n",
+				dev_name(&rpmb->dev));
+			continue;
+		}
+		rpmb->rdev = rdev;
+	}
+}
+
 static int mmc_blk_probe(struct mmc_card *card)
 {
 	struct mmc_blk_data *md;
···
 		pm_runtime_set_active(&card->dev);
 		pm_runtime_enable(&card->dev);
 	}
+
+	mmc_blk_rpmb_add(card);
 
 	return 0;