From 907d2e7cc7ebba4ab398422a7f0435e1802be65b Mon Sep 17 00:00:00 2001 From: Adrian Hunter Date: Wed, 29 Feb 2012 09:17:21 +0200 Subject: mmc: start removing enable / disable API Most parts of the enable / disable API are no longer used and can be removed. Signed-off-by: Adrian Hunter Tested-by: Venkatraman S Tested-by: Jaehoon Chung Signed-off-by: Chris Ball --- drivers/mmc/host/davinci_mmc.c | 4 ---- 1 file changed, 4 deletions(-) (limited to 'drivers/mmc/host/davinci_mmc.c') diff --git a/drivers/mmc/host/davinci_mmc.c b/drivers/mmc/host/davinci_mmc.c index 64a8325a4a8a..8de9c9bdba0b 100644 --- a/drivers/mmc/host/davinci_mmc.c +++ b/drivers/mmc/host/davinci_mmc.c @@ -1418,17 +1418,14 @@ static int davinci_mmcsd_suspend(struct device *dev) struct mmc_davinci_host *host = platform_get_drvdata(pdev); int ret; - mmc_host_enable(host->mmc); ret = mmc_suspend_host(host->mmc); if (!ret) { writel(0, host->base + DAVINCI_MMCIM); mmc_davinci_reset_ctrl(host, 1); - mmc_host_disable(host->mmc); clk_disable(host->clk); host->suspended = 1; } else { host->suspended = 0; - mmc_host_disable(host->mmc); } return ret; @@ -1444,7 +1441,6 @@ static int davinci_mmcsd_resume(struct device *dev) return 0; clk_enable(host->clk); - mmc_host_enable(host->mmc); mmc_davinci_reset_ctrl(host, 0); ret = mmc_resume_host(host->mmc); -- cgit v1.2.3 From be7b5622e608189894c2c440c3fb0138f122071f Mon Sep 17 00:00:00 2001 From: Ido Yariv Date: Sun, 11 Mar 2012 23:39:58 +0200 Subject: mmc: davinci: Eliminate spurious interrupts The davinci mmc interrupt handler fills the fifo, as long as the DXRDY or DRRDY bits are set in the status register. If interrupts fire during this loop, they will be handled by the handler, but the interrupt controller will still buffer these. As a result, the handler will be called again to serve these needlessly. In order to avoid these spurious interrupts, keep interrupts masked while filling the fifo. Signed-off-by: Ido Yariv Tested-by: Rajashekhara, Sudhakar Signed-off-by: Chris Ball --- drivers/mmc/host/davinci_mmc.c | 33 +++++++++++++++++++++++++++------ 1 file changed, 27 insertions(+), 6 deletions(-) (limited to 'drivers/mmc/host/davinci_mmc.c') diff --git a/drivers/mmc/host/davinci_mmc.c b/drivers/mmc/host/davinci_mmc.c index 8de9c9bdba0b..1e076fb06ac3 100644 --- a/drivers/mmc/host/davinci_mmc.c +++ b/drivers/mmc/host/davinci_mmc.c @@ -1009,12 +1009,33 @@ static irqreturn_t mmc_davinci_irq(int irq, void *dev_id) * by read. So, it is not unbouned loop even in the case of * non-dma. */ - while (host->bytes_left && (status & (MMCST0_DXRDY | MMCST0_DRRDY))) { - davinci_fifo_data_trans(host, rw_threshold); - status = readl(host->base + DAVINCI_MMCST0); - if (!status) - break; - qstatus |= status; + if (host->bytes_left && (status & (MMCST0_DXRDY | MMCST0_DRRDY))) { + unsigned long im_val; + + /* + * If interrupts fire during the following loop, they will be + * handled by the handler, but the PIC will still buffer these. + * As a result, the handler will be called again to serve these + * needlessly. In order to avoid these spurious interrupts, + * keep interrupts masked during the loop. + */ + im_val = readl(host->base + DAVINCI_MMCIM); + writel(0, host->base + DAVINCI_MMCIM); + + do { + davinci_fifo_data_trans(host, rw_threshold); + status = readl(host->base + DAVINCI_MMCST0); + qstatus |= status; + } while (host->bytes_left && + (status & (MMCST0_DXRDY | MMCST0_DRRDY))); + + /* + * If an interrupt is pending, it is assumed it will fire when + * it is unmasked. This assumption is also taken when the MMCIM + * is first set. Otherwise, writing to MMCIM after reading the + * status is race-prone. + */ + writel(im_val, host->base + DAVINCI_MMCIM); } if (qstatus & MMCST0_DATDNE) { -- cgit v1.2.3 From ee698f503442741ca394d55c77b61c9080537686 Mon Sep 17 00:00:00 2001 From: Ido Yariv Date: Sun, 11 Mar 2012 23:39:59 +0200 Subject: mmc: davinci: Poll status for small size transfers For small size non-dma sdio transactions, it is sometimes better to poll the mmc host and avoid interrupts altogether. Polling lowers the number of interrupts and context switches. Tests have shown that for small transactions, only a few polling iterations are needed, so this is worth while. Signed-off-by: Ido Yariv Tested-by: Rajashekhara, Sudhakar Signed-off-by: Chris Ball --- drivers/mmc/host/davinci_mmc.c | 29 ++++++++++++++++++++++++++++- 1 file changed, 28 insertions(+), 1 deletion(-) (limited to 'drivers/mmc/host/davinci_mmc.c') diff --git a/drivers/mmc/host/davinci_mmc.c b/drivers/mmc/host/davinci_mmc.c index 1e076fb06ac3..c1f3673ae1ef 100644 --- a/drivers/mmc/host/davinci_mmc.c +++ b/drivers/mmc/host/davinci_mmc.c @@ -160,6 +160,16 @@ module_param(rw_threshold, uint, S_IRUGO); MODULE_PARM_DESC(rw_threshold, "Read/Write threshold. Default = 32"); +static unsigned poll_threshold = 128; +module_param(poll_threshold, uint, S_IRUGO); +MODULE_PARM_DESC(poll_threshold, + "Polling transaction size threshold. Default = 128"); + +static unsigned poll_loopcount = 32; +module_param(poll_loopcount, uint, S_IRUGO); +MODULE_PARM_DESC(poll_loopcount, + "Maximum polling loop count. Default = 32"); + static unsigned __initdata use_dma = 1; module_param(use_dma, uint, 0); MODULE_PARM_DESC(use_dma, "Whether to use DMA or not. Default = 1"); @@ -193,6 +203,7 @@ struct mmc_davinci_host { bool use_dma; bool do_dma; bool sdio_int; + bool active_request; /* Scatterlist DMA uses one or more parameter RAM entries: * the main one (associated with rxdma or txdma) plus zero or @@ -219,6 +230,7 @@ struct mmc_davinci_host { #endif }; +static irqreturn_t mmc_davinci_irq(int irq, void *dev_id); /* PIO only */ static void mmc_davinci_sg_to_buf(struct mmc_davinci_host *host) @@ -376,7 +388,20 @@ static void mmc_davinci_start_command(struct mmc_davinci_host *host, writel(cmd->arg, host->base + DAVINCI_MMCARGHL); writel(cmd_reg, host->base + DAVINCI_MMCCMD); - writel(im_val, host->base + DAVINCI_MMCIM); + + host->active_request = true; + + if (!host->do_dma && host->bytes_left <= poll_threshold) { + u32 count = poll_loopcount; + + while (host->active_request && count--) { + mmc_davinci_irq(0, host); + cpu_relax(); + } + } + + if (host->active_request) + writel(im_val, host->base + DAVINCI_MMCIM); } /*----------------------------------------------------------------------*/ @@ -915,6 +940,7 @@ mmc_davinci_xfer_done(struct mmc_davinci_host *host, struct mmc_data *data) if (!data->stop || (host->cmd && host->cmd->error)) { mmc_request_done(host->mmc, data->mrq); writel(0, host->base + DAVINCI_MMCIM); + host->active_request = false; } else mmc_davinci_start_command(host, data->stop); } @@ -942,6 +968,7 @@ static void mmc_davinci_cmd_done(struct mmc_davinci_host *host, cmd->mrq->cmd->retries = 0; mmc_request_done(host->mmc, cmd->mrq); writel(0, host->base + DAVINCI_MMCIM); + host->active_request = false; } } -- cgit v1.2.3