Since sdhci_bcm_kona_sd_card_emulate() can be called from interrupt
context, we must use a spinlock instead of a mutex. This change
essentially restores the way things worked before the change to
mutexes in http://www.spinics.net/lists/linux-mmc/msg20276.html.

Without this change, we see "scheduling while atomic" errors.

Signed-off-by: Markus Mayer <markus.ma...@linaro.org>
---
 drivers/mmc/host/sdhci-bcm-kona.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/mmc/host/sdhci-bcm-kona.c 
b/drivers/mmc/host/sdhci-bcm-kona.c
index 7a190fe..f1b0a62 100644
--- a/drivers/mmc/host/sdhci-bcm-kona.c
+++ b/drivers/mmc/host/sdhci-bcm-kona.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2013 Broadcom Corporation
+ * Copyright (C) 2013-2014 Broadcom Corporation
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License as
@@ -53,7 +53,7 @@
 #define KONA_MMC_AUTOSUSPEND_DELAY             (50)
 
 struct sdhci_bcm_kona_dev {
-       struct mutex    write_lock; /* protect back to back writes */
+       spinlock_t write_lock; /* protect back to back writes */
 };
 
 
@@ -135,7 +135,7 @@ static int sdhci_bcm_kona_sd_card_emulate(struct sdhci_host 
*host, int insert)
         * insert-removal.
         * We keep 20uS
         */
-       mutex_lock(&kona_dev->write_lock);
+       spin_lock_bh(&kona_dev->write_lock);
        udelay(20);
        val = sdhci_readl(host, KONA_SDHOST_CORESTAT);
 
@@ -153,7 +153,7 @@ static int sdhci_bcm_kona_sd_card_emulate(struct sdhci_host 
*host, int insert)
                val &= ~KONA_SDHOST_CD_SW;
                sdhci_writel(host, val, KONA_SDHOST_CORESTAT);
        }
-       mutex_unlock(&kona_dev->write_lock);
+       spin_unlock_bh(&kona_dev->write_lock);
 
        return 0;
 }
@@ -247,7 +247,7 @@ static int sdhci_bcm_kona_probe(struct platform_device 
*pdev)
        pltfm_priv = sdhci_priv(host);
 
        kona_dev = sdhci_pltfm_priv(pltfm_priv);
-       mutex_init(&kona_dev->write_lock);
+       spin_lock_init(&kona_dev->write_lock);
 
        mmc_of_parse(host->mmc);
 
-- 
1.9.0

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