From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from buildserver.ru.mvista.com (unknown [213.79.90.228]) by ozlabs.org (Postfix) with ESMTP id 2A62DDE2AD for ; Tue, 17 Mar 2009 08:14:02 +1100 (EST) Date: Tue, 17 Mar 2009 00:14:00 +0300 From: Anton Vorontsov To: Pierre Ossman Subject: [PATCH 08/11] sdhci: Add quirk for controllers that need small delays for PIO Message-ID: <20090316211400.GH9375@oksana.dev.rtsoft.ru> References: <20090316211306.GA1736@oksana.dev.rtsoft.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 In-Reply-To: <20090316211306.GA1736@oksana.dev.rtsoft.ru> Cc: Ben Dooks , Arnd Bergmann , Liu Dave , linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org, sdhci-devel@list.drzeus.cx List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 --- drivers/mmc/host/sdhci.c | 3 +++ drivers/mmc/host/sdhci.h | 2 ++ 2 files changed, 5 insertions(+), 0 deletions(-) diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index 75d0ecb..cd6dab3 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -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 diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h index b9bc622..c5ce9ee 100644 --- a/drivers/mmc/host/sdhci.h +++ b/drivers/mmc/host/sdhci.h @@ -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 */ -- 1.5.6.5