Commit 7f7a201a authored by Doug Brown's avatar Doug Brown Committed by Ulf Hansson
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mmc: sdhci-pxav2: add register workaround for PXA168 silicon bug 



The PXA168 has a documented silicon bug that results in a data abort
exception when accessing the SDHCI_HOST_VERSION register on SDH2 and
SDH4 through a 16-bit read. Implement the workaround described in the
errata, which performs a 32-bit read from a lower address instead. This
is safe to use on all four SDH peripherals.

Signed-off-by: default avatarDoug Brown <doug@schmorgal.com>
Acked-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20230116194401.20372-4-doug@schmorgal.com


Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent e7643950

drivers/mmc/host/sdhci-pxav2.c

+10 −0
Original line number Diff line number Diff line
@@ -80,6 +80,15 @@ static void pxav2_reset(struct sdhci_host *host, u8 mask) 
	}

}



static u16 pxav1_readw(struct sdhci_host *host, int reg)

{

	/* Workaround for data abort exception on SDH2 and SDH4 on PXA168 */

	if (reg == SDHCI_HOST_VERSION)

		return readl(host->ioaddr + SDHCI_HOST_VERSION - 2) >> 16;



	return readw(host->ioaddr + reg);

}



static void pxav2_mmc_set_bus_width(struct sdhci_host *host, int width)

{

	u8 ctrl;
@@ -107,6 +116,7 @@ struct sdhci_pxa_variant { 
};



static const struct sdhci_ops pxav1_sdhci_ops = {

	.read_w        = pxav1_readw,

	.set_clock     = sdhci_set_clock,

	.get_max_clock = sdhci_pltfm_clk_get_max_clock,

	.set_bus_width = pxav2_mmc_set_bus_width,