sdhci: Add quirk for controllers that need small delays for PIO (3e3bf207) · Commits · 戴 / test

Small udelay is needed to make eSDHC work in PIO mode. Without the delay reading causes endless interrupt storm, and writing corrupts data. The first guess would be that we must wait for some bit in some register, but I didn't find any reliable bits that change before and after the delay. Signed-off-by:

Anton Vorontsov <avorontsov@ru.mvista.com> Signed-off-by:

Pierre Ossman <drzeus@drzeus.cx>

drivers/mmc/host/sdhci.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -336,6 +336,9 @@ static void sdhci_transfer_pio(struct sdhci_host *host)
		mask = ~0;

		while (sdhci_readl(host, SDHCI_PRESENT_STATE) & mask) {
		if (host->quirks & SDHCI_QUIRK_PIO_NEEDS_DELAY)
		udelay(100);

		if (host->data->flags & MMC_DATA_READ)
		sdhci_read_block_pio(host);
		else

drivers/mmc/host/sdhci.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -220,6 +220,8 @@ struct sdhci_host {
		#define SDHCI_QUIRK_INVERTED_WRITE_PROTECT (1<<16)
		/* Controller has nonstandard clock management */
		#define SDHCI_QUIRK_NONSTANDARD_CLOCK (1<<17)
		/* Controller does not like fast PIO transfers */
		#define SDHCI_QUIRK_PIO_NEEDS_DELAY (1<<18)

		int irq; /* Device IRQ */
		void __iomem * ioaddr; /* Mapped address */

Admin message