Re: [PATCH] ARM: mmc: bcm281xx SDHCI driver

From: Stephen Warren
Date: Sat May 11 2013 - 00:28:47 EST


On 05/08/2013 11:55 PM, Christian Daudt wrote:
> Add SDHCI driver for the Broadcom 281xx SoCs. Also
> add bindings for it into bcm281xx dts files.
> Still missing:
> - power managemement

> diff --git a/drivers/mmc/host/sdhci-bcm-kona.c b/drivers/mmc/host/sdhci-bcm-kona.c

> + /*
> + * Back-to-Back register write needs a delay of 1ms at bootup (min 10uS)
> + * Back-to-Back writes to same register needs delay when SD bus clock
> + * is very low w.r.t AHB clock, mainly during boot-time and during card
> + * insert-removal.
> + */
> + udelay(1000);
> + sdhci_writel(host, val, KONA_SDHOST_CORECTRL);

This sounds very similar to the workaround in
drivers/mmc/host/sdhci-bcm2835.c. Is this the same IP block supported by
that driver? Perhaps not, since bcm2835 apparently needs other WARs such
as always using 32-bit IO and hence needing custom read/write w/b
functions to do read-modify-write which isn't here?
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