Commit 24552ccb authored by Doug Brown's avatar Doug Brown Committed by Ulf Hansson
Browse files

mmc: sdhci-pxav2: add SDIO card IRQ workaround for PXA168 V1 controller 



The PXA168 has a documented silicon bug that causes SDIO card IRQs to be
missed. Implement the first half of the suggested workaround, which
involves resetting the data port logic and issuing a dummy CMD0 to
restart the clock.

Signed-off-by: default avatarDoug Brown <doug@schmorgal.com>
Acked-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20230116194401.20372-7-doug@schmorgal.com


Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent e41c48b4

drivers/mmc/host/sdhci-pxav2.c

+55 −1
Original line number Diff line number Diff line
@@ -20,6 +20,8 @@ 
#include <linux/slab.h>

#include <linux/of.h>

#include <linux/of_device.h>

#include <linux/mmc/sdio.h>

#include <linux/mmc/mmc.h>



#include "sdhci.h"

#include "sdhci-pltfm.h"
@@ -41,6 +43,10 @@ 
#define MMC_CARD		0x1000

#define MMC_WIDTH		0x0100



struct sdhci_pxav2_host {

	struct mmc_request *sdio_mrq;

};



static void pxav2_reset(struct sdhci_host *host, u8 mask)

{

	struct platform_device *pdev = to_platform_device(mmc_dev(host->mmc));
@@ -89,6 +95,52 @@ static u16 pxav1_readw(struct sdhci_host *host, int reg) 
	return readw(host->ioaddr + reg);

}



static u32 pxav1_irq(struct sdhci_host *host, u32 intmask)

{

	struct sdhci_pxav2_host *pxav2_host = sdhci_pltfm_priv(sdhci_priv(host));

	struct mmc_request *sdio_mrq;



	if (pxav2_host->sdio_mrq && (intmask & SDHCI_INT_CMD_MASK)) {

		/* The dummy CMD0 for the SDIO workaround just completed */

		sdhci_writel(host, intmask & SDHCI_INT_CMD_MASK, SDHCI_INT_STATUS);

		intmask &= ~SDHCI_INT_CMD_MASK;

		sdio_mrq = pxav2_host->sdio_mrq;

		pxav2_host->sdio_mrq = NULL;

		mmc_request_done(host->mmc, sdio_mrq);

	}



	return intmask;

}



static void pxav1_request_done(struct sdhci_host *host, struct mmc_request *mrq)

{

	u16 tmp;

	struct sdhci_pxav2_host *pxav2_host;



	/* If this is an SDIO command, perform errata workaround for silicon bug */

	if (mrq->cmd && !mrq->cmd->error &&

	    (mrq->cmd->opcode == SD_IO_RW_DIRECT ||

	     mrq->cmd->opcode == SD_IO_RW_EXTENDED)) {

		/* Reset data port */

		tmp = readw(host->ioaddr + SDHCI_TIMEOUT_CONTROL);

		tmp |= 0x400;

		writew(tmp, host->ioaddr + SDHCI_TIMEOUT_CONTROL);



		/* Clock is now stopped, so restart it by sending a dummy CMD0 */

		pxav2_host = sdhci_pltfm_priv(sdhci_priv(host));

		pxav2_host->sdio_mrq = mrq;

		sdhci_writel(host, 0, SDHCI_ARGUMENT);

		sdhci_writew(host, 0, SDHCI_TRANSFER_MODE);

		sdhci_writew(host, SDHCI_MAKE_CMD(MMC_GO_IDLE_STATE, SDHCI_CMD_RESP_NONE),

			     SDHCI_COMMAND);



		/* Don't finish this request until the dummy CMD0 finishes */

		return;

	}



	mmc_request_done(host->mmc, mrq);

}



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

{

	u8 ctrl;
@@ -118,10 +170,12 @@ struct sdhci_pxa_variant { 
static const struct sdhci_ops pxav1_sdhci_ops = {

	.read_w        = pxav1_readw,

	.set_clock     = sdhci_set_clock,

	.irq           = pxav1_irq,

	.get_max_clock = sdhci_pltfm_clk_get_max_clock,

	.set_bus_width = pxav2_mmc_set_bus_width,

	.reset         = pxav2_reset,

	.set_uhs_signaling = sdhci_set_uhs_signaling,

	.request_done  = pxav1_request_done,

};



static const struct sdhci_pxa_variant __maybe_unused pxav1_variant = {
@@ -193,7 +247,7 @@ static int sdhci_pxav2_probe(struct platform_device *pdev) 
	int ret;

	struct clk *clk, *clk_core;



	host = sdhci_pltfm_init(pdev, NULL, 0);

	host = sdhci_pltfm_init(pdev, NULL, sizeof(struct sdhci_pxav2_host));

	if (IS_ERR(host))

		return PTR_ERR(host);