s3cmci: Kconfig selection for PIO/DMA/Both

Add a selection for the data transfer mode of the s3cmci driver, allowing
for either a configuration or rumtime selection of the use of the DMA or
PIO transfer code.

The PIO only mode is 476 bytes smaller than the driver with both methods
compiled in.

Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/arm/plat-s3c24xx/include/plat/mci.h b/arch/arm/plat-s3c24xx/include/plat/mci.h
index 2d0852ac3b272d57a66271ce4edee234ccb53e96..f1bd6d4198d4d547c20d305dcff840976a89349e 100644 (file)
--- a/arch/arm/plat-s3c24xx/include/plat/mci.h
+++ b/arch/arm/plat-s3c24xx/include/plat/mci.h
@@ -4,6 +4,7 @@
 struct s3c24xx_mci_pdata {
        unsigned int    wprotect_invert : 1;
        unsigned int    detect_invert : 1;   /* set => detect active high. */
+       unsigned int    use_dma : 1;
 
        unsigned int    gpio_detect;
        unsigned int    gpio_wprotect;

diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
index 7cb057f3f883837e1fc05e459eef0f3b8219201f..cf6a6545240b7e3f63aabef9cd79209447ee0d84 100644 (file)
--- a/drivers/mmc/host/Kconfig
+++ b/drivers/mmc/host/Kconfig
@@ -276,6 +276,40 @@ config MMC_S3C
 
          If unsure, say N.
 
+choice
+       prompt "Samsung S3C SD/MMC transfer code"
+       depends on MMC_S3C
+
+config MMC_S3C_PIO
+       bool "Use PIO transfers only"
+       help
+         Use PIO to transfer data between memory and the hardware.
+
+         PIO is slower than DMA as it requires CPU instructions to
+         move the data. This has been the traditional default for
+         the S3C MCI driver.
+
+config MMC_S3C_DMA
+       bool "Use DMA transfers only (EXPERIMENTAL)"
+       depends on EXPERIMENTAL
+       help
+         Use DMA to transfer data between memory and the hardare.
+
+         Currently, the DMA support in this driver seems to not be
+         working properly and needs to be debugged before this
+         option is useful.
+
+config MMC_S3C_PIODMA
+       bool "Support for both PIO and DMA (EXPERIMENTAL)"
+       help
+         Compile both the PIO and DMA transfer routines into the
+         driver and let the platform select at run-time which one
+         is best.
+
+         See notes for the DMA option.
+
+endchoice
+
 config MMC_SDRICOH_CS
        tristate "MMC/SD driver for Ricoh Bay1Controllers (EXPERIMENTAL)"
        depends on EXPERIMENTAL && PCI && PCMCIA

diff --git a/drivers/mmc/host/s3cmci.c b/drivers/mmc/host/s3cmci.c
index 7660ac4572e505a83ab5c4da6a748bac03c46cff..0adf31895f2a81842bcf3c238a94d0efa274effd 100644 (file)
--- a/drivers/mmc/host/s3cmci.c
+++ b/drivers/mmc/host/s3cmci.c
@@ -164,6 +164,25 @@ static void dbg_dumpregs(struct s3cmci_host *host, char *prefix) { }
 
 #endif /* CONFIG_MMC_DEBUG */
 
+/**
+ * s3cmci_host_usedma - return whether the host is using dma or pio
+ * @host: The host state
+ *
+ * Return true if the host is using DMA to transfer data, else false
+ * to use PIO mode. Will return static data depending on the driver
+ * configuration.
+ */
+static inline bool s3cmci_host_usedma(struct s3cmci_host *host)
+{
+#ifdef CONFIG_MMC_S3C_PIO
+       return false;
+#elif defined(CONFIG_MMC_S3C_DMA)
+       return true;
+#else
+       return host->dodma;
+#endif
+}
+
 static inline u32 enable_imask(struct s3cmci_host *host, u32 imask)
 {
        u32 newmask;
@@ -560,7 +579,7 @@ static irqreturn_t s3cmci_irq(int irq, void *dev_id)
                goto irq_out;
        }
 
-       if (!host->dodma) {
+       if (!s3cmci_host_usedma(host)) {
                if ((host->pio_active == XFER_WRITE) &&
                    (mci_fsta & S3C2410_SDIFSTA_TFDET)) {
 
@@ -796,7 +815,7 @@ static void finalize_request(struct s3cmci_host *host)
 
        if (cmd->data && (cmd->error == 0) &&
            (cmd->data->error == 0)) {
-               if (host->dodma && (!host->dma_complete)) {
+               if (s3cmci_host_usedma(host) && (!host->dma_complete)) {
                        dbg(host, dbg_dma, "DMA Missing!\n");
                        return;
                }
@@ -848,7 +867,7 @@ static void finalize_request(struct s3cmci_host *host)
        /* If we had an error while transfering data we flush the
         * DMA channel and the fifo to clear out any garbage. */
        if (mrq->data->error != 0) {
-               if (host->dodma)
+               if (s3cmci_host_usedma(host))
                        s3c2410_dma_ctrl(host->dma, S3C2410_DMAOP_FLUSH);
 
                if (host->is2440) {
@@ -968,7 +987,7 @@ static int s3cmci_setup_data(struct s3cmci_host *host, struct mmc_data *data)
 
        dcon  = data->blocks & S3C2410_SDIDCON_BLKNUM_MASK;
 
-       if (host->dodma)
+       if (s3cmci_host_usedma(host))
                dcon |= S3C2410_SDIDCON_DMAEN;
 
        if (host->bus_width == MMC_BUS_WIDTH_4)
@@ -1114,7 +1133,7 @@ static void s3cmci_send_request(struct mmc_host *mmc)
                        return;
                }
 
-               if (host->dodma)
+               if (s3cmci_host_usedma(host))
                        res = s3cmci_prepare_dma(host, cmd->data);
                else
                        res = s3cmci_prepare_pio(host, cmd->data);
@@ -1398,7 +1417,7 @@ static int s3cmci_state_show(struct seq_file *seq, void *v)
        seq_printf(seq, "IRQ disabled = %d\n", host->irq_disabled);
        seq_printf(seq, "IRQ state = %d\n", host->irq_state);
        seq_printf(seq, "CD IRQ = %d\n", host->irq_cd);
-       seq_printf(seq, "Do DMA = %d\n", host->dodma);
+       seq_printf(seq, "Do DMA = %d\n", s3cmci_host_usedma(host));
        seq_printf(seq, "SDIIMSK at %d\n", host->sdiimsk);
        seq_printf(seq, "SDIDATA at %d\n", host->sdidata);
 
@@ -1559,12 +1578,15 @@ static int __devinit s3cmci_probe(struct platform_device *pdev)
                host->clk_div   = 2;
        }
 
-       host->dodma             = 0;
        host->complete_what     = COMPLETION_NONE;
        host->pio_active        = XFER_NONE;
 
        host->dma               = S3CMCI_DMA;
 
+#ifdef CONFIG_MMC_S3C_PIODMA
+       host->dodma             = host->pdata->dma;
+#endif
+
        host->mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!host->mem) {
                dev_err(&pdev->dev,
@@ -1702,7 +1724,8 @@ static int __devinit s3cmci_probe(struct platform_device *pdev)
        s3cmci_debugfs_attach(host);
 
        platform_set_drvdata(pdev, mmc);
-       dev_info(&pdev->dev, "initialisation done.\n");
+       dev_info(&pdev->dev, "%s - using %s\n", mmc_hostname(mmc),
+                s3cmci_host_usedma(host) ? "dma" : "pio");
 
        return 0;