This patch adds the compile time configuration option for the
atmel-mci driver to reset the Atmel MCI controller before every
command.
This is sometimes needed for the Atmel controller / board to function
properly. In the case of the at91sam9g20-ek this is needed.
Please read the whole set, try it out, and comment.
Thank you,
Rob Emanuele
---
drivers/mmc/host/Kconfig | 10 ++++++++++
drivers/mmc/host/atmel-mci.c | 11 ++++++++++-
2 files changed, 20 insertions(+), 1 deletions(-)
diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
index 6e2f52b..9e24029 100644
--- a/drivers/mmc/host/Kconfig
+++ b/drivers/mmc/host/Kconfig
@@ -150,6 +150,16 @@ config MMC_ATMELMCI
endchoice
+config MMC_ATMELMCI_ALWAYS_RESET
+ bool "Reset before every request. Sometimes needed for buggy chips."
+ depends on MMC_ATMELMCI
+ help
+ There are reports that some buggy controllers work better
+ with a reset before every command. This may improve your
+ controller's reliability.
+
+ If unsure, say N.
+
config MMC_ATMELMCI_DMA
bool "Atmel MCI DMA support (EXPERIMENTAL)"
depends on MMC_ATMELMCI && AVR32 && DMA_ENGINE && EXPERIMENTAL
diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
index 497dd51..b133baa 100644
--- a/drivers/mmc/host/atmel-mci.c
+++ b/drivers/mmc/host/atmel-mci.c
@@ -65,6 +65,15 @@ struct atmel_mci_dma {
#endif
};
+/*
+ * Configuration options from the kernel config
+ */
+#ifdef CONFIG_MMC_ATMELMCI_ALWAYS_RESET
+#define MMC_ALWAYS_RESET 1
+#else
+#define MMC_ALWAYS_RESET 0
+#endif
+
/**
* struct atmel_mci - MMC controller state shared between all slots
* @lock: Spinlock protecting the queue and associated data.
@@ -714,7 +723,7 @@ static void atmci_start_request(struct atmel_mci *host,
host->completed_events = 0;
host->data_status = 0;
- if (host->need_reset) {
+ if (host->need_reset || MMC_ALWAYS_RESET) {
mci_writel(host, CR, MCI_CR_SWRST);
mci_writel(host, CR, MCI_CR_MCIEN);
mci_writel(host, MR, host->mode_reg);
--
1.6.0.4