[PATCH] sd: read-only switch

Support for the read-only switch on SD cards which must be enforced by the
host.

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

4 files changed, 34 insertions, 18 deletions

diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index 294961a102ca..725c6ad3eb64 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -413,8 +413,7 @@ static void mmc_decode_cid(struct mmc_card *card)
                 card->cid.month                 = UNSTUFF_BITS(resp, 8, 4);
 
                 card->cid.year += 2000; /* SD cards year offset */
-        }
-        else {
+        } else {
                 /*
                  * The selection of the format here is based upon published
                  * specs from sandisk and from what people have reported.
@@ -494,8 +493,7 @@ static void mmc_decode_csd(struct mmc_card *card)
                 csd->capacity     = (1 + m) << (e + 2);
 
                 csd->read_blkbits = UNSTUFF_BITS(resp, 80, 4);
-        }
-        else {
+        } else {
                 /*
                  * We only understand CSD structure v1.1 and v1.2.
                  * v1.2 has extra information in bits 15, 11 and 10.
@@ -738,10 +736,20 @@ static void mmc_discover_cards(struct mmc_host *host)
                         err = mmc_wait_for_cmd(host, &cmd, CMD_RETRIES);
                         if (err != MMC_ERR_NONE)
                                 mmc_card_set_dead(card);
-                        else
+                        else {
                                 card->rca = cmd.resp[0] >> 16;
-                }
-                else {
+
+                                if (!host->ops->get_ro) {
+                                        printk(KERN_WARNING "%s: host does not "
+                                                "support reading read-only "
+                                                "switch. assuming write-enable.\n",
+                                                mmc_hostname(host));
+                                } else {
+                                        if (host->ops->get_ro(host))
+                                                mmc_card_set_readonly(card);
+                                }
+                        }
+                } else {
                         cmd.opcode = MMC_SET_RELATIVE_ADDR;
                         cmd.arg = card->rca << 16;
                         cmd.flags = MMC_RSP_R1;
@@ -833,24 +841,23 @@ static void mmc_setup(struct mmc_host *host)
                 int err;
                 u32 ocr;
 
-                host->mode = MMC_MODE_MMC;
+                host->mode = MMC_MODE_SD;
 
                 mmc_power_up(host);
                 mmc_idle_cards(host);
 
-                err = mmc_send_op_cond(host, 0, &ocr);
+                err = mmc_send_app_op_cond(host, 0, &ocr);
 
                 /*
-                 * If we fail to detect any cards then try
-                 * searching for SD cards.
+                 * If we fail to detect any SD cards then try
+                 * searching for MMC cards.
                  */
-                if (err != MMC_ERR_NONE)
-                {
-                        err = mmc_send_app_op_cond(host, 0, &ocr);
+                if (err != MMC_ERR_NONE) {
+                        host->mode = MMC_MODE_MMC;
+
+                        err = mmc_send_op_cond(host, 0, &ocr);
                         if (err != MMC_ERR_NONE)
                                 return;
-
-                        host->mode = MMC_MODE_SD;
                 }
 
                 host->ocr = mmc_select_voltage(host, ocr);
diff --git a/drivers/mmc/mmc_block.c b/drivers/mmc/mmc_block.c
index d4eee99c2bf6..fa83f15fdf16 100644
--- a/drivers/mmc/mmc_block.c
+++ b/drivers/mmc/mmc_block.c
@@ -95,6 +95,10 @@ static int mmc_blk_open(struct inode *inode, struct file *filp)
                 if (md->usage == 2)
                         check_disk_change(inode->i_bdev);
                 ret = 0;
+
+                if ((filp->f_mode & FMODE_WRITE) &&
+                        mmc_card_readonly(md->queue.card))
+                        ret = -EROFS;
         }
 
         return ret;
@@ -403,9 +407,10 @@ static int mmc_blk_probe(struct mmc_card *card)
         if (err)
                 goto out;
 
-        printk(KERN_INFO "%s: %s %s %dKiB\n",
+        printk(KERN_INFO "%s: %s %s %dKiB %s\n",
                 md->disk->disk_name, mmc_card_id(card), mmc_card_name(card),
-                (card->csd.capacity << card->csd.read_blkbits) / 1024);
+                (card->csd.capacity << card->csd.read_blkbits) / 1024,
+                mmc_card_readonly(card)?"(ro)":"");
 
         mmc_set_drvdata(card, md);
         add_disk(md->disk);
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index 538e8c86336c..0e9ec01b9c5b 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -48,6 +48,7 @@ struct mmc_card {
 #define MMC_STATE_DEAD          (1<<1)          /* device no longer in stack */
 #define MMC_STATE_BAD           (1<<2)          /* unrecognised device */
 #define MMC_STATE_SDCARD        (1<<3)          /* is an SD card */
+#define MMC_STATE_READONLY      (1<<4)          /* card is read-only */
         u32                     raw_cid[4];     /* raw card CID */
         u32                     raw_csd[4];     /* raw card CSD */
         struct mmc_cid          cid;            /* card identification */
@@ -58,11 +59,13 @@ struct mmc_card {
 #define mmc_card_dead(c)        ((c)->state & MMC_STATE_DEAD)
 #define mmc_card_bad(c)         ((c)->state & MMC_STATE_BAD)
 #define mmc_card_sd(c)          ((c)->state & MMC_STATE_SDCARD)
+#define mmc_card_readonly(c)    ((c)->state & MMC_STATE_READONLY)
 
 #define mmc_card_set_present(c) ((c)->state |= MMC_STATE_PRESENT)
 #define mmc_card_set_dead(c)    ((c)->state |= MMC_STATE_DEAD)
 #define mmc_card_set_bad(c)     ((c)->state |= MMC_STATE_BAD)
 #define mmc_card_set_sd(c)      ((c)->state |= MMC_STATE_SDCARD)
+#define mmc_card_set_readonly(c) ((c)->state |= MMC_STATE_READONLY)
 
 #define mmc_card_name(c)        ((c)->cid.prod_name)
 #define mmc_card_id(c)          ((c)->dev.bus_id)
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 845020d90c60..8c5f71376e41 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -62,6 +62,7 @@ struct mmc_ios {
 struct mmc_host_ops {
         void    (*request)(struct mmc_host *host, struct mmc_request *req);
         void    (*set_ios)(struct mmc_host *host, struct mmc_ios *ios);
+        int     (*get_ro)(struct mmc_host *host);
 };
 
 struct mmc_card;