[PATCH] sd: SCR register

Read the SD specific SCR register from the card.

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>

1 files changed, 133 insertions, 10 deletions

diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index 725c6ad3eb64..21d4fb3314f8 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -16,6 +16,8 @@
 #include <linux/delay.h>
 #include <linux/pagemap.h>
 #include <linux/err.h>
+#include <asm/scatterlist.h>
+#include <linux/scatterlist.h>
 
 #include <linux/mmc/card.h>
 #include <linux/mmc/host.h>
@@ -246,6 +248,8 @@ int mmc_wait_for_app_cmd(struct mmc_host *host, unsigned int rca,
 
 EXPORT_SYMBOL(mmc_wait_for_app_cmd);
 
+static int mmc_select_card(struct mmc_host *host, struct mmc_card *card);
+
 /**
  *      __mmc_claim_host - exclusively claim a host
  *      @host: mmc host to claim
@@ -278,16 +282,10 @@ int __mmc_claim_host(struct mmc_host *host, struct mmc_card *card)
         spin_unlock_irqrestore(&host->lock, flags);
         remove_wait_queue(&host->wq, &wait);
 
-        if (card != (void *)-1 && host->card_selected != card) {
-                struct mmc_command cmd;
-
-                host->card_selected = card;
-
-                cmd.opcode = MMC_SELECT_CARD;
-                cmd.arg = card->rca << 16;
-                cmd.flags = MMC_RSP_R1;
-
-                err = mmc_wait_for_cmd(host, &cmd, CMD_RETRIES);
+        if (card != (void *)-1) {
+                err = mmc_select_card(host, card);
+                if (err != MMC_ERR_NONE)
+                        return err;
         }
 
         return err;
@@ -317,6 +315,29 @@ void mmc_release_host(struct mmc_host *host)
 
 EXPORT_SYMBOL(mmc_release_host);
 
+static int mmc_select_card(struct mmc_host *host, struct mmc_card *card)
+{
+        int err;
+        struct mmc_command cmd;
+
+        BUG_ON(host->card_busy == NULL);
+
+        if (host->card_selected == card)
+                return MMC_ERR_NONE;
+
+        host->card_selected = card;
+
+        cmd.opcode = MMC_SELECT_CARD;
+        cmd.arg = card->rca << 16;
+        cmd.flags = MMC_RSP_R1;
+
+        err = mmc_wait_for_cmd(host, &cmd, CMD_RETRIES);
+        if (err != MMC_ERR_NONE)
+                return err;
+
+        return MMC_ERR_NONE;
+}
+
 /*
  * Ensure that no card is selected.
  */
@@ -526,6 +547,32 @@ static void mmc_decode_csd(struct mmc_card *card)
 }
 
 /*
+ * Given a 64-bit response, decode to our card SCR structure.
+ */
+static void mmc_decode_scr(struct mmc_card *card)
+{
+        struct sd_scr *scr = &card->scr;
+        unsigned int scr_struct;
+        u32 resp[4];
+
+        BUG_ON(!mmc_card_sd(card));
+
+        resp[3] = card->raw_scr[1];
+        resp[2] = card->raw_scr[0];
+
+        scr_struct = UNSTUFF_BITS(resp, 60, 4);
+        if (scr_struct != 0) {
+                printk("%s: unrecognised SCR structure version %d\n",
+                        mmc_hostname(card->host), scr_struct);
+                mmc_card_set_bad(card);
+                return;
+        }
+
+        scr->sda_vsn = UNSTUFF_BITS(resp, 56, 4);
+        scr->bus_widths = UNSTUFF_BITS(resp, 48, 4);
+}
+
+/*
  * Locate a MMC card on this MMC host given a raw CID.
  */
 static struct mmc_card *mmc_find_card(struct mmc_host *host, u32 *raw_cid)
@@ -789,6 +836,79 @@ static void mmc_read_csds(struct mmc_host *host)
         }
 }
 
+static void mmc_read_scrs(struct mmc_host *host)
+{
+        int err;
+        struct mmc_card *card;
+
+        struct mmc_request mrq;
+        struct mmc_command cmd;
+        struct mmc_data data;
+
+        struct scatterlist sg;
+
+        list_for_each_entry(card, &host->cards, node) {
+                if (card->state & (MMC_STATE_DEAD|MMC_STATE_PRESENT))
+                        continue;
+                if (!mmc_card_sd(card))
+                        continue;
+
+                err = mmc_select_card(host, card);
+                if (err != MMC_ERR_NONE) {
+                        mmc_card_set_dead(card);
+                        continue;
+                }
+
+                memset(&cmd, 0, sizeof(struct mmc_command));
+
+                cmd.opcode = MMC_APP_CMD;
+                cmd.arg = card->rca << 16;
+                cmd.flags = MMC_RSP_R1;
+
+                err = mmc_wait_for_cmd(host, &cmd, 0);
+                if ((err != MMC_ERR_NONE) || !(cmd.resp[0] & R1_APP_CMD)) {
+                        mmc_card_set_dead(card);
+                        continue;
+                }
+
+                memset(&cmd, 0, sizeof(struct mmc_command));
+
+                cmd.opcode = SD_APP_SEND_SCR;
+                cmd.arg = 0;
+                cmd.flags = MMC_RSP_R1;
+
+                memset(&data, 0, sizeof(struct mmc_data));
+
+                data.timeout_ns = card->csd.tacc_ns * 10;
+                data.timeout_clks = card->csd.tacc_clks * 10;
+                data.blksz_bits = 3;
+                data.blocks = 1;
+                data.flags = MMC_DATA_READ;
+                data.sg = &sg;
+                data.sg_len = 1;
+
+                memset(&mrq, 0, sizeof(struct mmc_request));
+
+                mrq.cmd = &cmd;
+                mrq.data = &data;
+
+                sg_init_one(&sg, (u8*)card->raw_scr, 8);
+
+                err = mmc_wait_for_req(host, &mrq);
+                if (err != MMC_ERR_NONE) {
+                        mmc_card_set_dead(card);
+                        continue;
+                }
+
+                card->raw_scr[0] = ntohl(card->raw_scr[0]);
+                card->raw_scr[1] = ntohl(card->raw_scr[1]);
+
+                mmc_decode_scr(card);
+        }
+
+        mmc_deselect_cards(host);
+}
+
 static unsigned int mmc_calculate_clock(struct mmc_host *host)
 {
         struct mmc_card *card;
@@ -912,6 +1032,9 @@ static void mmc_setup(struct mmc_host *host)
         host->ops->set_ios(host, &host->ios);
 
         mmc_read_csds(host);
+
+        if (host->mode == MMC_MODE_SD)
+                mmc_read_scrs(host);
 }