From: Jocelyn Bohr <b...@google.com>
The linux kernel driver for this module does not use a delay when
writing to the SDHCI_BUFFER register. This patch mimics that behavior
in order to speed up the mmc writes on the Raspberry Pi.
Signed-off-by: Alex Deymo <de...@google.com>
---
drivers/mmc/bcm2835_sdhci.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/mmc/bcm2835_sdhci.c b/drivers/mmc/bcm2835_sdhci.c
index 29c2a85812..20079bce48 100644
--- a/drivers/mmc/bcm2835_sdhci.c
+++ b/drivers/mmc/bcm2835_sdhci.c
@@ -44,6 +44,7 @@
/* 400KHz is max freq for card ID etc. Use that as min */
#define MIN_FREQ 400000
+#define SDHCI_BUFFER 0x20
struct bcm2835_sdhci_host {
struct sdhci_host host;
@@ -69,8 +70,11 @@ static inline void bcm2835_sdhci_raw_writel(struct
sdhci_host *host, u32 val,
* (Which is just as well - otherwise we'd have to nobble the DMA engine
* too)
*/
- while (timer_get_us() - bcm_host->last_write < bcm_host->twoticks_delay)
- ;
+ if (reg != SDHCI_BUFFER) {
+ while (timer_get_us() - bcm_host->last_write <
+ bcm_host->twoticks_delay)
+ ;
+ }
writel(val, host->ioaddr + reg);
bcm_host->last_write = timer_get_us();
--
2.12.2.564.g063fe858b8-goog
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