mmc: Fix sd/sdio/mmc initialization frequency retries

Rewrite and clean up mmc_rescan() to properly retry frequencies lower
than 400kHz.  Failures can happen both in sd_send_* calls and
mmc_attach_*.  Break out "mmc_rescan_try_freq" from the frequency
selection loop.  Symmetrize claim/release logic in mmc_attach_* API,
and move the sd_send_* calls there to make mmc_rescan easier to read.

Signed-off-by: Andy Ross <andy.ross@windriver.com>
Reviewed-and-Tested-by: Hein Tibosch <hein_tibosch@yahoo.es>
Reviewed-by: Chris Ball <cjb@laptop.org>
Signed-off-by: Chris Ball <cjb@laptop.org>

1 files changed, 36 insertions, 83 deletions

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 97e0624eb9b6..198f70bad908 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -1485,25 +1485,41 @@ int mmc_set_blocklen(struct mmc_card *card, unsigned int blocklen)
 }
 EXPORT_SYMBOL(mmc_set_blocklen);
 
+static int mmc_rescan_try_freq(struct mmc_host *host, unsigned freq)
+{
+        host->f_init = freq;
+
+#ifdef CONFIG_MMC_DEBUG
+        pr_info("%s: %s: trying to init card at %u Hz\n",
+                mmc_hostname(host), __func__, host->f_init);
+#endif
+        mmc_power_up(host);
+        sdio_reset(host);
+        mmc_go_idle(host);
+
+        mmc_send_if_cond(host, host->ocr_avail);
+
+        /* Order's important: probe SDIO, then SD, then MMC */
+        if (!mmc_attach_sdio(host))
+                return 0;
+        if (!mmc_attach_sd(host))
+                return 0;
+        if (!mmc_attach_mmc(host))
+                return 0;
+
+        mmc_power_off(host);
+        return -EIO;
+}
+
 void mmc_rescan(struct work_struct *work)
 {
+        static const unsigned freqs[] = { 400000, 300000, 200000, 100000 };
         struct mmc_host *host =
                 container_of(work, struct mmc_host, detect.work);
-        u32 ocr;
-        int err;
-        unsigned long flags;
         int i;
-        const unsigned freqs[] = { 400000, 300000, 200000, 100000 };
-
-        spin_lock_irqsave(&host->lock, flags);
 
-        if (host->rescan_disable) {
-                spin_unlock_irqrestore(&host->lock, flags);
+        if (host->rescan_disable)
                 return;
-        }
-
-        spin_unlock_irqrestore(&host->lock, flags);
-
 
         mmc_bus_get(host);
 
@@ -1526,8 +1542,6 @@ void mmc_rescan(struct work_struct *work)
                 goto out;
         }
 
-        /* detect a newly inserted card */
-
         /*
          * Only we can add a new handler, so it's safe to
          * release the lock here.
@@ -1537,77 +1551,16 @@ void mmc_rescan(struct work_struct *work)
         if (host->ops->get_cd && host->ops->get_cd(host) == 0)
                 goto out;
 
+        mmc_claim_host(host);
         for (i = 0; i < ARRAY_SIZE(freqs); i++) {
-                mmc_claim_host(host);
-
-                if (freqs[i] >= host->f_min)
-                        host->f_init = freqs[i];
-                else if (!i || freqs[i-1] > host->f_min)
-                        host->f_init = host->f_min;
-                else {
-                        mmc_release_host(host);
-                        goto out;
-                }
-#ifdef CONFIG_MMC_DEBUG
-                pr_info("%s: %s: trying to init card at %u Hz\n",
-                        mmc_hostname(host), __func__, host->f_init);
-#endif
-                mmc_power_up(host);
-                sdio_reset(host);
-                mmc_go_idle(host);
-
-                mmc_send_if_cond(host, host->ocr_avail);
-
-                /*
-                 * First we search for SDIO...
-                 */
-                err = mmc_send_io_op_cond(host, 0, &ocr);
-                if (!err) {
-                        if (mmc_attach_sdio(host, ocr)) {
-                                mmc_claim_host(host);
-                                /*
-                                 * Try SDMEM (but not MMC) even if SDIO
-                                 * is broken.
-                                 */
-                                mmc_power_up(host);
-                                sdio_reset(host);
-                                mmc_go_idle(host);
-                                mmc_send_if_cond(host, host->ocr_avail);
-
-                                if (mmc_send_app_op_cond(host, 0, &ocr))
-                                        goto out_fail;
-
-                                if (mmc_attach_sd(host, ocr))
-                                        mmc_power_off(host);
-                        }
-                        goto out;
-                }
-
-                /*
-                 * ...then normal SD...
-                 */
-                err = mmc_send_app_op_cond(host, 0, &ocr);
-                if (!err) {
-                        if (mmc_attach_sd(host, ocr))
-                                mmc_power_off(host);
-                        goto out;
-                }
-
-                /*
-                 * ...and finally MMC.
-                 */
-                err = mmc_send_op_cond(host, 0, &ocr);
-                if (!err) {
-                        if (mmc_attach_mmc(host, ocr))
-                                mmc_power_off(host);
-                        goto out;
-                }
-
-out_fail:
-                mmc_release_host(host);
-                mmc_power_off(host);
+                if (!mmc_rescan_try_freq(host, max(freqs[i], host->f_min)))
+                        break;
+                if (freqs[i] < host->f_min)
+                        break;
         }
-out:
+        mmc_release_host(host);
+
+ out:
         if (host->caps & MMC_CAP_NEEDS_POLL)
                 mmc_schedule_delayed_work(&host->detect, HZ);
 }