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mmc: bcm2835_sdhci: Speed up mmc writes.

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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 <deymo@google.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
This commit is contained in:
Jocelyn Bohr 2017-04-02 01:24:33 -07:00 committed by Jaehoon Chung
parent c86c0155dc
commit 4db2b61fcf
1 changed files with 6 additions and 2 deletions
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8
drivers/mmc/bcm2835_sdhci.c
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@ -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();