Re: [RFC PATCH v4 1/9] mmc: dw_mmc: Add external dma interface support

Alim Akhtar
2015-08-10T18:04:05Z

Hi Shawn

On Thu, Aug 6, 2015 at 12:14 PM, Shawn Lin <shawn.lin@rock-chips.com> wrote:
> DesignWare MMC Controller can supports two types of DMA
> mode: external dma and internal dma. We get a RK312x platform
> integrated dw_mmc and ARM pl330 dma controller. This patch add
> edmac ops to support these platforms. I've tested it on RK312x
> platform with edmac mode and RK3288 platform with idmac mode.
>
Just curious to know if their are any performance (read/write)
difference with Idmac and edmac?

> Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
>
> ---
>
> Changes in v4:
> - remove "host->trans_mode" and use "host->use_dma" to indicate
> transfer mode.
> - remove all bt-bindings' changes since we don't need new properities.
> - check transfer mode at runtime by reading HCON reg
> - spilt defconfig changes for each sub-architecture
> - fix the title of cover letter
> - reuse some code for reducing code size
>
> Changes in v3:
> - choose transfer mode at runtime
> - remove all CONFIG_MMC_DW_IDMAC config option
> - add supports-idmac property for some platforms
>
> Changes in v2:
> - Fix typo of dev_info msg
> - remove unused dmach from declaration of dw_mci_dma_slave
>
> drivers/mmc/host/Kconfig | 11 +-
> drivers/mmc/host/dw_mmc-pltfm.c | 2 +
> drivers/mmc/host/dw_mmc.c | 258 ++++++++++++++++++++++++++++++++--------
> include/linux/mmc/dw_mmc.h | 27 ++++-
> 4 files changed, 232 insertions(+), 66 deletions(-)
>
> diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
> index 6a0f9c7..a86c0eb 100644
> --- a/drivers/mmc/host/Kconfig
> +++ b/drivers/mmc/host/Kconfig
> @@ -607,15 +607,7 @@ config MMC_DW
> help
> This selects support for the Synopsys DesignWare Mobile Storage IP
> block, this provides host support for SD and MMC interfaces, in both
> - PIO and external DMA modes.
> -
> -config MMC_DW_IDMAC
> - bool "Internal DMAC interface"
> - depends on MMC_DW
> - help
> - This selects support for the internal DMAC block within the Synopsys
> - Designware Mobile Storage IP block. This disables the external DMA
> - interface.
> + PIO, internal DMA mode and external DMA modes.
>
> config MMC_DW_PLTFM
> tristate "Synopsys Designware MCI Support as platform device"
> @@ -644,7 +636,6 @@ config MMC_DW_K3
> tristate "K3 specific extensions for Synopsys DW Memory Card Interface"
> depends on MMC_DW
> select MMC_DW_PLTFM
> - select MMC_DW_IDMAC
> help
> This selects support for Hisilicon K3 SoC specific extensions to the
> Synopsys DesignWare Memory Card Interface driver. Select this option
> diff --git a/drivers/mmc/host/dw_mmc-pltfm.c b/drivers/mmc/host/dw_mmc-pltfm.c
> index ec6dbcd..7e1d13b 100644
> --- a/drivers/mmc/host/dw_mmc-pltfm.c
> +++ b/drivers/mmc/host/dw_mmc-pltfm.c
> @@ -59,6 +59,8 @@ int dw_mci_pltfm_register(struct platform_device *pdev,
> host->pdata = pdev->dev.platform_data;
>
> regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + /* Get registers' physical base address */
> + host->phy_regs = (void *)(regs->start);
> host->regs = devm_ioremap_resource(&pdev->dev, regs);
> if (IS_ERR(host->regs))
> return PTR_ERR(host->regs);
> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> index 40e9d8e..5d6cdff 100644
> --- a/drivers/mmc/host/dw_mmc.c
> +++ b/drivers/mmc/host/dw_mmc.c
> @@ -56,7 +56,7 @@
> #define DW_MCI_FREQ_MAX 200000000 /* unit: HZ */
> #define DW_MCI_FREQ_MIN 400000 /* unit: HZ */
>
> -#ifdef CONFIG_MMC_DW_IDMAC
> +
> #define IDMAC_INT_CLR (SDMMC_IDMAC_INT_AI | SDMMC_IDMAC_INT_NI | \
> SDMMC_IDMAC_INT_CES | SDMMC_IDMAC_INT_DU | \
> SDMMC_IDMAC_INT_FBE | SDMMC_IDMAC_INT_RI | \
> @@ -99,7 +99,6 @@ struct idmac_desc {
>
> __le32 des3; /* buffer 2 physical address */
> };
> -#endif /* CONFIG_MMC_DW_IDMAC */
>
> static bool dw_mci_reset(struct dw_mci *host);
> static bool dw_mci_ctrl_reset(struct dw_mci *host, u32 reset);
> @@ -403,7 +402,6 @@ static int dw_mci_get_dma_dir(struct mmc_data *data)
> return DMA_FROM_DEVICE;
> }
>
> -#ifdef CONFIG_MMC_DW_IDMAC
> static void dw_mci_dma_cleanup(struct dw_mci *host)
> {
> struct mmc_data *data = host->data;
> @@ -441,12 +439,21 @@ static void dw_mci_idmac_stop_dma(struct dw_mci *host)
> mci_writel(host, BMOD, temp);
> }
>
> -static void dw_mci_idmac_complete_dma(struct dw_mci *host)
> +static void dw_mci_dmac_complete_dma(void *arg)
> {
> + struct dw_mci *host = arg;
> struct mmc_data *data = host->data;
>
> dev_vdbg(host->dev, "DMA complete\n");
>
> + if (host->use_dma == TRANS_MODE_EDMAC)
> + if (data && (data->flags & MMC_DATA_READ))
> + /* Invalidate cache after read */
> + dma_sync_sg_for_cpu(mmc_dev(host->cur_slot->mmc),
> + data->sg,
> + data->sg_len,
> + DMA_FROM_DEVICE);
> +
> host->dma_ops->cleanup(host);
>
> /*
> @@ -527,7 +534,7 @@ static void dw_mci_translate_sglist(struct dw_mci *host, struct mmc_data *data,
> wmb();
> }
>
> -static void dw_mci_idmac_start_dma(struct dw_mci *host, unsigned int sg_len)
> +static int dw_mci_idmac_start_dma(struct dw_mci *host, unsigned int sg_len)
> {
> u32 temp;
>
> @@ -551,6 +558,8 @@ static void dw_mci_idmac_start_dma(struct dw_mci *host, unsigned int sg_len)
>
> /* Start it running */
> mci_writel(host, PLDMND, 1);
> +
> + return 0;
> }
>
> static int dw_mci_idmac_init(struct dw_mci *host)
> @@ -629,10 +638,112 @@ static const struct dw_mci_dma_ops dw_mci_idmac_ops = {
> .init = dw_mci_idmac_init,
> .start = dw_mci_idmac_start_dma,
> .stop = dw_mci_idmac_stop_dma,
> - .complete = dw_mci_idmac_complete_dma,
> + .complete = dw_mci_dmac_complete_dma,
> + .cleanup = dw_mci_dma_cleanup,
> +};
> +
> +static void dw_mci_edmac_stop_dma(struct dw_mci *host)
> +{
> + dmaengine_terminate_all(host->dms->ch);
> +}
> +
> +static int dw_mci_edmac_start_dma(struct dw_mci *host,
> + unsigned int sg_len)
> +{
> + struct dma_slave_config cfg;
> + struct dma_async_tx_descriptor *desc = NULL;
> + struct scatterlist *sgl = host->data->sg;
> + const u32 mszs[] = {1, 4, 8, 16, 32, 64, 128, 256};
> + u32 sg_elems = host->data->sg_len;
> + u32 fifoth_val;
> + u32 fifo_offset = host->fifo_reg - host->regs;
> + int ret = 0;
> +
> + /* Set external dma config: burst size, burst width */
> + cfg.dst_addr = (dma_addr_t)(host->phy_regs + fifo_offset);
> + cfg.src_addr = cfg.dst_addr;
> + cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
> + cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
> +
> + /* Match burst msize with external dma config */
> + fifoth_val = mci_readl(host, FIFOTH);
> + cfg.dst_maxburst = mszs[(fifoth_val >> 28) & 0x7];
> + cfg.src_maxburst = cfg.dst_maxburst;
> +
> + if (host->data->flags & MMC_DATA_WRITE)
> + cfg.direction = DMA_MEM_TO_DEV;
> + else /* MMC_DATA_READ */
> + cfg.direction = DMA_DEV_TO_MEM;
> +
> + ret = dmaengine_slave_config(host->dms->ch, &cfg);
> + if (ret) {
> + dev_err(host->dev, "Failed to config edmac.\n");
> + return -EBUSY;
> + }
> +
> + desc = dmaengine_prep_slave_sg(host->dms->ch, sgl,
> + sg_len, cfg.direction,
> + DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
> + if (!desc) {
> + dev_err(host->dev, "Can't prepare slave sg.\n");
> + return -EBUSY;
> + }
> +
> + /* Set dw_mci_edmac_complete_dma as callback */
> + desc->callback = dw_mci_dmac_complete_dma;
> + desc->callback_param = (void *)host;
> + dmaengine_submit(desc);
> +
> + /* Flush cache before write */
> + if (host->data->flags & MMC_DATA_WRITE)
> + dma_sync_sg_for_device(mmc_dev(host->cur_slot->mmc), sgl,
> + sg_elems, DMA_TO_DEVICE);
> +
> + dma_async_issue_pending(host->dms->ch);
> +
> + return 0;
> +}
> +
> +static int dw_mci_edmac_init(struct dw_mci *host)
> +{
> + /* Request external dma channel */
> + host->dms = kzalloc(sizeof(struct dw_mci_dma_slave), GFP_KERNEL);
> + if (!host->dms)
> + return -ENOMEM;
> +
> + host->dms->ch = dma_request_slave_channel(host->dev, "rx-tx");
> + if (!host->dms->ch) {
> + dev_err(host->dev,
> + "Failed to get external DMA channel %d\n",
> + host->dms->ch->chan_id);
> + kfree(host->dms);
> + host->dms = NULL;
> + return -ENXIO;
> + }
> +
> + return 0;
> +}
> +
> +static void dw_mci_edmac_exit(struct dw_mci *host)
> +{
> + if (host->dms) {
> + if (host->dms->ch) {
> + dma_release_channel(host->dms->ch);
> + host->dms->ch = NULL;
> + }
> + kfree(host->dms);
> + host->dms = NULL;
> + }
> +}
> +
> +static const struct dw_mci_dma_ops dw_mci_edmac_ops = {
> + .init = dw_mci_edmac_init,
> + .exit = dw_mci_edmac_exit,
> + .start = dw_mci_edmac_start_dma,
> + .stop = dw_mci_edmac_stop_dma,
> + .complete = dw_mci_dmac_complete_dma,
> .cleanup = dw_mci_dma_cleanup,
> };
> -#endif /* CONFIG_MMC_DW_IDMAC */
>
> static int dw_mci_pre_dma_transfer(struct dw_mci *host,
> struct mmc_data *data,
> @@ -712,7 +823,6 @@ static void dw_mci_post_req(struct mmc_host *mmc,
>
> static void dw_mci_adjust_fifoth(struct dw_mci *host, struct mmc_data *data)
> {
> -#ifdef CONFIG_MMC_DW_IDMAC
> unsigned int blksz = data->blksz;
> const u32 mszs[] = {1, 4, 8, 16, 32, 64, 128, 256};
> u32 fifo_width = 1 << host->data_shift;
> @@ -720,6 +830,10 @@ static void dw_mci_adjust_fifoth(struct dw_mci *host, struct mmc_data *data)
> u32 msize = 0, rx_wmark = 1, tx_wmark, tx_wmark_invers;
> int idx = (sizeof(mszs) / sizeof(mszs[0])) - 1;
>
> + /* pio should ship this scenario */
> + if (!host->use_dma)
> + return;
> +
> tx_wmark = (host->fifo_depth) / 2;
> tx_wmark_invers = host->fifo_depth - tx_wmark;
>
> @@ -748,7 +862,6 @@ static void dw_mci_adjust_fifoth(struct dw_mci *host, struct mmc_data *data)
> done:
> fifoth_val = SDMMC_SET_FIFOTH(msize, rx_wmark, tx_wmark);
> mci_writel(host, FIFOTH, fifoth_val);
> -#endif
> }
>
> static void dw_mci_ctrl_rd_thld(struct dw_mci *host, struct mmc_data *data)
> @@ -835,7 +948,11 @@ static int dw_mci_submit_data_dma(struct dw_mci *host, struct mmc_data *data)
> mci_writel(host, INTMASK, temp);
> spin_unlock_irqrestore(&host->irq_lock, irqflags);
>
> - host->dma_ops->start(host, sg_len);
> + if (host->dma_ops->start(host, sg_len)) {
> + /* We can't do DMA */
> + dev_err(host->dev, "%s: failed to start DMA.\n", __func__);
> + return -ENODEV;
> + }
>
> return 0;
> }
> @@ -2256,26 +2373,30 @@ static irqreturn_t dw_mci_interrupt(int irq, void *dev_id)
>
> }
>
> -#ifdef CONFIG_MMC_DW_IDMAC
> - /* Handle DMA interrupts */
> - if (host->dma_64bit_address == 1) {
> - pending = mci_readl(host, IDSTS64);
> - if (pending & (SDMMC_IDMAC_INT_TI | SDMMC_IDMAC_INT_RI)) {
> - mci_writel(host, IDSTS64, SDMMC_IDMAC_INT_TI |
> - SDMMC_IDMAC_INT_RI);
> - mci_writel(host, IDSTS64, SDMMC_IDMAC_INT_NI);
> - host->dma_ops->complete(host);
> - }
> - } else {
> - pending = mci_readl(host, IDSTS);
> - if (pending & (SDMMC_IDMAC_INT_TI | SDMMC_IDMAC_INT_RI)) {
> - mci_writel(host, IDSTS, SDMMC_IDMAC_INT_TI |
> - SDMMC_IDMAC_INT_RI);
> - mci_writel(host, IDSTS, SDMMC_IDMAC_INT_NI);
> - host->dma_ops->complete(host);
> + if (host->use_dma == TRANS_MODE_IDMAC) {
> + /* Handle DMA interrupts */
> + if (host->dma_64bit_address == 1) {
> + pending = mci_readl(host, IDSTS64);
> + if (pending & (SDMMC_IDMAC_INT_TI |
> + SDMMC_IDMAC_INT_RI)) {
> + mci_writel(host, IDSTS64,
> + SDMMC_IDMAC_INT_TI |
> + SDMMC_IDMAC_INT_RI);
> + mci_writel(host, IDSTS64, SDMMC_IDMAC_INT_NI);
> + host->dma_ops->complete((void *)host);
> + }
> + } else {
> + pending = mci_readl(host, IDSTS);
> + if (pending & (SDMMC_IDMAC_INT_TI |
> + SDMMC_IDMAC_INT_RI)) {
> + mci_writel(host, IDSTS,
> + SDMMC_IDMAC_INT_TI |
> + SDMMC_IDMAC_INT_RI);
> + mci_writel(host, IDSTS, SDMMC_IDMAC_INT_NI);
> + host->dma_ops->complete((void *)host);
> + }
> }
> }
> -#endif
>
> return IRQ_HANDLED;
> }
> @@ -2391,19 +2512,28 @@ static int dw_mci_init_slot(struct dw_mci *host, unsigned int id)
> mmc->max_seg_size = host->pdata->blk_settings->max_seg_size;
> } else {
> /* Useful defaults if platform data is unset. */
> -#ifdef CONFIG_MMC_DW_IDMAC
> - mmc->max_segs = host->ring_size;
> - mmc->max_blk_size = 65536;
> - mmc->max_seg_size = 0x1000;
> - mmc->max_req_size = mmc->max_seg_size * host->ring_size;
> - mmc->max_blk_count = mmc->max_req_size / 512;
> -#else
> - mmc->max_segs = 64;
> - mmc->max_blk_size = 65536; /* BLKSIZ is 16 bits */
> - mmc->max_blk_count = 512;
> - mmc->max_req_size = mmc->max_blk_size * mmc->max_blk_count;
> - mmc->max_seg_size = mmc->max_req_size;
> -#endif /* CONFIG_MMC_DW_IDMAC */
> + if (host->use_dma == TRANS_MODE_IDMAC) {
> + mmc->max_segs = host->ring_size;
> + mmc->max_blk_size = 65536;
> + mmc->max_seg_size = 0x1000;
> + mmc->max_req_size = mmc->max_seg_size * host->ring_size;
> + mmc->max_blk_count = mmc->max_req_size / 512;
> + } else if (host->use_dma == TRANS_MODE_EDMAC) {
> + mmc->max_segs = 64;
> + mmc->max_blk_size = 65536;
> + mmc->max_blk_count = 65535;
> + mmc->max_req_size =
> + mmc->max_blk_size * mmc->max_blk_count;
> + mmc->max_seg_size = mmc->max_req_size;
> + } else {
> + /* TRANS_MODE_PIO */
> + mmc->max_segs = 64;
> + mmc->max_blk_size = 65536; /* BLKSIZ is 16 bits */
> + mmc->max_blk_count = 512;
> + mmc->max_req_size =
> + mmc->max_blk_size * mmc->max_blk_count;
> + mmc->max_seg_size = mmc->max_req_size;
> + }
> }
>
> if (dw_mci_get_cd(mmc))
> @@ -2437,6 +2567,21 @@ static void dw_mci_cleanup_slot(struct dw_mci_slot *slot, unsigned int id)
> static void dw_mci_init_dma(struct dw_mci *host)
> {
> int addr_config;
> + int trans_mode;
> + struct device *dev = host->dev;
> + struct device_node *np = dev->of_node;
> +
> + /* Check tansfer mode */
> + trans_mode = (mci_readl(host, HCON) >> 16) & 0x3;
> + if (trans_mode == 0) {
> + trans_mode = TRANS_MODE_IDMAC;
> + } else if (trans_mode == 1 || trans_mode == 2) {
> + trans_mode = TRANS_MODE_EDMAC;
> + } else {
> + trans_mode = TRANS_MODE_PIO;
> + goto no_dma;
> + }
> +
> /* Check ADDR_CONFIG bit in HCON to find IDMAC address bus width */
> addr_config = (mci_readl(host, HCON) >> 27) & 0x01;
>
> @@ -2462,10 +2607,19 @@ static void dw_mci_init_dma(struct dw_mci *host)
> }
>
> /* Determine which DMA interface to use */
> -#ifdef CONFIG_MMC_DW_IDMAC
> - host->dma_ops = &dw_mci_idmac_ops;
> - dev_info(host->dev, "Using internal DMA controller.\n");
> -#endif
> + if (trans_mode == TRANS_MODE_IDMAC) {
> + host->dma_ops = &dw_mci_idmac_ops;
> + dev_info(host->dev, "Using internal DMA controller.\n");
> + } else {
> + /* TRANS_MODE_EDMAC: check dma bindings again */
> + if ((of_property_count_strings(np, "dma-names") < 0) ||
> + (!of_find_property(np, "dmas", NULL))) {
> + trans_mode = TRANS_MODE_PIO;
> + goto no_dma;
> + }
> + host->dma_ops = &dw_mci_edmac_ops;
> + dev_info(host->dev, "Using external DMA controller.\n");
> + }
>
> if (!host->dma_ops)
> goto no_dma;
> @@ -2482,12 +2636,12 @@ static void dw_mci_init_dma(struct dw_mci *host)
> goto no_dma;
> }
>
> - host->use_dma = 1;
> + host->use_dma = trans_mode;
> return;
>
> no_dma:
> dev_info(host->dev, "Using PIO mode.\n");
> - host->use_dma = 0;
> + host->use_dma = trans_mode;
> return;
> }
>
> @@ -2570,10 +2724,9 @@ static bool dw_mci_reset(struct dw_mci *host)
> }
> }
>
> -#if IS_ENABLED(CONFIG_MMC_DW_IDMAC)
> - /* It is also recommended that we reset and reprogram idmac */
> - dw_mci_idmac_reset(host);
> -#endif
> + if (host->use_dma == TRANS_MODE_IDMAC)
> + /* It is also recommended that we reset and reprogram idmac */
> + dw_mci_idmac_reset(host);
>
> ret = true;
>
> @@ -2958,6 +3111,9 @@ EXPORT_SYMBOL(dw_mci_remove);
> */
> int dw_mci_suspend(struct dw_mci *host)
> {
> + if (host->use_dma && host->dma_ops->exit)
> + host->dma_ops->exit(host);
> +
> return 0;
> }
> EXPORT_SYMBOL(dw_mci_suspend);
> diff --git a/include/linux/mmc/dw_mmc.h b/include/linux/mmc/dw_mmc.h
> index 5be9767..9ed6257 100644
> --- a/include/linux/mmc/dw_mmc.h
> +++ b/include/linux/mmc/dw_mmc.h
> @@ -16,6 +16,7 @@
>
> #include <linux/scatterlist.h>
> #include <linux/mmc/core.h>
> +#include <linux/dmaengine.h>
>
> #define MAX_MCI_SLOTS 2
>
> @@ -40,6 +41,17 @@ enum {
>
> struct mmc_data;
>
> +enum {
> + TRANS_MODE_PIO = 0,
> + TRANS_MODE_IDMAC,
> + TRANS_MODE_EDMAC
> +};
> +
> +struct dw_mci_dma_slave {
> + struct dma_chan *ch;
> + enum dma_transfer_direction direction;
> +};
> +
> /**
> * struct dw_mci - MMC controller state shared between all slots
> * @lock: Spinlock protecting the queue and associated data.
> @@ -153,11 +165,16 @@ struct dw_mci {
> dma_addr_t sg_dma;
> void *sg_cpu;
> const struct dw_mci_dma_ops *dma_ops;
> -#ifdef CONFIG_MMC_DW_IDMAC
> + /* For idmac */
> unsigned int ring_size;
> -#else
> +
> + /* For edmac */
> + struct dw_mci_dma_slave *dms;
> + /* Registers's physical base address */
> + void *phy_regs;
> +
> struct dw_mci_dma_data *dma_data;
> -#endif
> +
> u32 cmd_status;
> u32 data_status;
> u32 stop_cmdr;
> @@ -210,8 +227,8 @@ struct dw_mci {
> struct dw_mci_dma_ops {
> /* DMA Ops */
> int (*init)(struct dw_mci *host);
> - void (*start)(struct dw_mci *host, unsigned int sg_len);
> - void (*complete)(struct dw_mci *host);
> + int (*start)(struct dw_mci *host, unsigned int sg_len);
> + void (*complete)(void *host);
> void (*stop)(struct dw_mci *host);
> void (*cleanup)(struct dw_mci *host);
> void (*exit)(struct dw_mci *host);
> --
> 2.3.7
>
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html

--
Regards,
Alim