From b08bb35d1a5ee5426198eb3a2861008c2e9e6fc4 Mon Sep 17 00:00:00 2001 From: Sahitya Tummala Date: Wed, 8 Dec 2010 15:03:05 +0530 Subject: [PATCH] mmc: msm_sdcc: Reset SDCC in case of data transfer errors SDCC uses an asynchronous FIFOs for data synchronization (one for TX and one for RX). For any error when DPSM (Data path state machine) is involved the transfer is terminated with the remaining data stuck inside FIFOs. Reset the controller in case of data errors to ensure that any left over data in FIFOs is flushed out and DPSM is in good state. The following problems are observed without this reset functionality - 1. After the card is removed in an unsafe way (removed when there is an on going data transfer), the card will not be detected upon its next insertion. This is because the controller wouldn't respond to few initialization commands. 2. When an error occurs for a data transfer in non-DMA mode, sometimes we get spurious PIO interrupt after the request is processed. Signed-off-by: Sahitya Tummala Signed-off-by: David Brown --- drivers/mmc/host/msm_sdcc.c | 39 +++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) diff --git a/drivers/mmc/host/msm_sdcc.c b/drivers/mmc/host/msm_sdcc.c index 67f536ca31d3..81ed16fb42b5 100644 --- a/drivers/mmc/host/msm_sdcc.c +++ b/drivers/mmc/host/msm_sdcc.c @@ -44,6 +44,7 @@ #include #include #include +#include #include "msm_sdcc.h" @@ -126,6 +127,40 @@ static void msmsdcc_start_command(struct msmsdcc_host *host, struct mmc_command *cmd, u32 c); +static void msmsdcc_reset_and_restore(struct msmsdcc_host *host) +{ + u32 mci_clk = 0; + u32 mci_mask0 = 0; + int ret = 0; + + /* Save the controller state */ + mci_clk = readl(host->base + MMCICLOCK); + mci_mask0 = readl(host->base + MMCIMASK0); + + /* Reset the controller */ + ret = clk_reset(host->clk, CLK_RESET_ASSERT); + if (ret) + pr_err("%s: Clock assert failed at %u Hz with err %d\n", + mmc_hostname(host->mmc), host->clk_rate, ret); + + ret = clk_reset(host->clk, CLK_RESET_DEASSERT); + if (ret) + pr_err("%s: Clock deassert failed at %u Hz with err %d\n", + mmc_hostname(host->mmc), host->clk_rate, ret); + + pr_info("%s: Controller has been re-initialiazed\n", + mmc_hostname(host->mmc)); + + /* Restore the contoller state */ + writel(host->pwr, host->base + MMCIPOWER); + writel(mci_clk, host->base + MMCICLOCK); + writel(mci_mask0, host->base + MMCIMASK0); + ret = clk_set_rate(host->clk, host->clk_rate); + if (ret) + pr_err("%s: Failed to set clk rate %u Hz (%d)\n", + mmc_hostname(host->mmc), host->clk_rate, ret); +} + static void msmsdcc_request_end(struct msmsdcc_host *host, struct mmc_request *mrq) { @@ -223,6 +258,8 @@ msmsdcc_dma_complete_tlet(unsigned long data) pr_err("Flush data: %.8x %.8x %.8x %.8x %.8x %.8x\n", err.flush[0], err.flush[1], err.flush[2], err.flush[3], err.flush[4], err.flush[5]); + + msmsdcc_reset_and_restore(host); if (!mrq->data->error) mrq->data->error = -EIO; } @@ -723,6 +760,7 @@ static void msmsdcc_do_cmdirq(struct msmsdcc_host *host, uint32_t status) msm_dmov_stop_cmd(host->dma.channel, &host->dma.hdr, 0); else if (host->curr.data) { /* Non DMA */ + msmsdcc_reset_and_restore(host); msmsdcc_stop_data(host); msmsdcc_request_end(host, cmd->mrq); } else { /* host->data == NULL */ @@ -771,6 +809,7 @@ msmsdcc_handle_irq_data(struct msmsdcc_host *host, u32 status, msm_dmov_stop_cmd(host->dma.channel, &host->dma.hdr, 0); else { + msmsdcc_reset_and_restore(host); if (host->curr.data) msmsdcc_stop_data(host); if (!data->stop) -- 2.20.1