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

Joachim Eastwood
2015-08-07T21:32:11Z

Hi Shawn,

On 6 August 2015 at 08:44, 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.
>
> Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>

> @@ -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) {

Doing:
if (host->use_dma != TRANS_MODE_IDMAC)
return IRQ_HANDLED;

Could save you the extra level of identation you add below.

> + /* 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;
> }

> @@ -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;

I think it would be nice if you could add some defines for 16 and 0x03
or add a macro like SDMMC_GET_FCNT() that is in dw_mmc.h.

> + 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;

I'll try to get this patch tested on my lpc18xx platform soon.
btw, the HCON reg on lpc18xx reads as 0x00e42cc1 (address 0x40004070).

regard,
Joachim Eastwood