sdhci: describe quirks

[linux-2.6-omap-h63xx.git] / drivers / mmc / host / sdhci.c

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index d7c5b94d8c583de00136f8c8f2e435347375b497..17b4e391db3590a02feb53b931cfc3f30abed30d 100644 (file)
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -17,8 +17,6 @@
 
 #include <linux/mmc/host.h>
 
-#include <asm/scatterlist.h>
-
 #include "sdhci.h"
 
 #define DRIVER_NAME "sdhci"
@@ -28,12 +26,22 @@
 
 static unsigned int debug_quirks = 0;
 
+/*
+ * Different quirks to handle when the hardware deviates from a strict
+ * interpretation of the SDHCI specification.
+ */
+
+/* Controller doesn't honor resets unless we touch the clock register */
 #define SDHCI_QUIRK_CLOCK_BEFORE_RESET                 (1<<0)
+/* Controller has bad caps bits, but really supports DMA */
 #define SDHCI_QUIRK_FORCE_DMA                          (1<<1)
 /* Controller doesn't like some resets when there is no card inserted. */
 #define SDHCI_QUIRK_NO_CARD_NO_RESET                   (1<<2)
+/* Controller doesn't like clearing the power reg before a change */
 #define SDHCI_QUIRK_SINGLE_POWER_WRITE                 (1<<3)
+/* Controller has flaky internal state so reset it on each ios change */
 #define SDHCI_QUIRK_RESET_CMD_DATA_ON_IOS              (1<<4)
+/* Controller has an unusable DMA engine */
 #define SDHCI_QUIRK_BROKEN_DMA                         (1<<5)
 
 static const struct pci_device_id pci_ids[] __devinitdata = {
@@ -1303,7 +1311,7 @@ static int __devinit sdhci_probe_slot(struct pci_dev *pdev, int slot)
 
        if ((chip->quirks & SDHCI_QUIRK_BROKEN_DMA) &&
                (host->flags & SDHCI_USE_DMA)) {
-               DBG("Disabling DMA as it is marked broken");
+               DBG("Disabling DMA as it is marked broken\n");
                host->flags &= ~SDHCI_USE_DMA;
        }