| Message ID | 20190527124307.32075-3-narmstrong@baylibre.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | mmc: meson-gx: add dram-access-quirk support | expand |
On Mon, 27 May 2019 at 14:43, Neil Armstrong <narmstrong@baylibre.com> wrote: > > On the Amlogic G12A SoC family, (only) the SDIO controller fails to access > the data from DRAM, leading to a broken controller. > > But each MMC controller has 1,5KiB of SRAM after the registers, that can > be used as bounce buffer to avoid direct DRAM access from the integrated > DMAs (this SRAM may be used by the boot ROM when DRAM is not yet initialized). > > The quirk is to disable the chained descriptor for this controller, and > use this SRAM memory zone as buffer for the bounce buffer fallback mode. > > The performance hit hasn't been evaluated, but the fix has been tested > using a WiFi AP6398S SDIO module, and the iperf3 Bandwidth measurement gave > 55.2 Mbits/sec over a 63 Hours long test, with the SDIO ios set as High-Speed > at 50MHz clock. It gave 170 Mbits/sec as SDR104 and 200MHz clock. > > Reviewed-by: Kevin Hilman <khilman@baylibre.com> > Tested-by: Guillaume La Roque <glaroque@baylibre.com> > Signed-off-by: Neil Armstrong <narmstrong@baylibre.com> Applied for next, thanks! Kind regards Uffe > --- > drivers/mmc/host/meson-gx-mmc.c | 70 ++++++++++++++++++++++++++------- > 1 file changed, 55 insertions(+), 15 deletions(-) > > diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c > index c5a8af4ca76b..bcf1789d26b6 100644 > --- a/drivers/mmc/host/meson-gx-mmc.c > +++ b/drivers/mmc/host/meson-gx-mmc.c > @@ -129,6 +129,9 @@ > #define SD_EMMC_TXD 0x94 > #define SD_EMMC_LAST_REG SD_EMMC_TXD > > +#define SD_EMMC_SRAM_DATA_BUF_LEN 1536 > +#define SD_EMMC_SRAM_DATA_BUF_OFF 0x200 > + > #define SD_EMMC_CFG_BLK_SIZE 512 /* internal buffer max: 512 bytes */ > #define SD_EMMC_CFG_RESP_TIMEOUT 256 /* in clock cycles */ > #define SD_EMMC_CMD_TIMEOUT 1024 /* in ms */ > @@ -168,6 +171,8 @@ struct meson_host { > unsigned long req_rate; > bool ddr; > > + bool dram_access_quirk; > + > struct pinctrl *pinctrl; > struct pinctrl_state *pins_default; > struct pinctrl_state *pins_clk_gate; > @@ -232,11 +237,20 @@ static struct mmc_command *meson_mmc_get_next_command(struct mmc_command *cmd) > static void meson_mmc_get_transfer_mode(struct mmc_host *mmc, > struct mmc_request *mrq) > { > + struct meson_host *host = mmc_priv(mmc); > struct mmc_data *data = mrq->data; > struct scatterlist *sg; > int i; > bool use_desc_chain_mode = true; > > + /* > + * When Controller DMA cannot directly access DDR memory, disable > + * support for Chain Mode to directly use the internal SRAM using > + * the bounce buffer mode. > + */ > + if (host->dram_access_quirk) > + return; > + > /* > * Broken SDIO with AP6255-based WiFi on Khadas VIM Pro has been > * reported. For some strange reason this occurs in descriptor > @@ -1049,6 +1063,10 @@ static int meson_mmc_probe(struct platform_device *pdev) > host->dev = &pdev->dev; > dev_set_drvdata(&pdev->dev, host); > > + /* The G12A SDIO Controller needs an SRAM bounce buffer */ > + host->dram_access_quirk = device_property_read_bool(&pdev->dev, > + "amlogic,dram-access-quirk"); > + > /* Get regulators and the supported OCR mask */ > host->vqmmc_enabled = false; > ret = mmc_regulator_get_supply(mmc); > @@ -1146,9 +1164,16 @@ static int meson_mmc_probe(struct platform_device *pdev) > goto err_init_clk; > > mmc->caps |= MMC_CAP_CMD23; > - mmc->max_blk_count = CMD_CFG_LENGTH_MASK; > + if (host->dram_access_quirk) { > + /* Limit to the available sram memory */ > + mmc->max_segs = SD_EMMC_SRAM_DATA_BUF_LEN / mmc->max_blk_size; > + mmc->max_blk_count = mmc->max_segs; > + } else { > + mmc->max_blk_count = CMD_CFG_LENGTH_MASK; > + mmc->max_segs = SD_EMMC_DESC_BUF_LEN / > + sizeof(struct sd_emmc_desc); > + } > mmc->max_req_size = mmc->max_blk_count * mmc->max_blk_size; > - mmc->max_segs = SD_EMMC_DESC_BUF_LEN / sizeof(struct sd_emmc_desc); > mmc->max_seg_size = mmc->max_req_size; > > /* > @@ -1158,15 +1183,27 @@ static int meson_mmc_probe(struct platform_device *pdev) > */ > mmc->caps2 &= ~MMC_CAP2_HS400; > > - /* data bounce buffer */ > - host->bounce_buf_size = mmc->max_req_size; > - host->bounce_buf = > - dma_alloc_coherent(host->dev, host->bounce_buf_size, > - &host->bounce_dma_addr, GFP_KERNEL); > - if (host->bounce_buf == NULL) { > - dev_err(host->dev, "Unable to map allocate DMA bounce buffer.\n"); > - ret = -ENOMEM; > - goto err_free_irq; > + if (host->dram_access_quirk) { > + /* > + * The MMC Controller embeds 1,5KiB of internal SRAM > + * that can be used to be used as bounce buffer. > + * In the case of the G12A SDIO controller, use these > + * instead of the DDR memory > + */ > + host->bounce_buf_size = SD_EMMC_SRAM_DATA_BUF_LEN; > + host->bounce_buf = host->regs + SD_EMMC_SRAM_DATA_BUF_OFF; > + host->bounce_dma_addr = res->start + SD_EMMC_SRAM_DATA_BUF_OFF; > + } else { > + /* data bounce buffer */ > + host->bounce_buf_size = mmc->max_req_size; > + host->bounce_buf = > + dma_alloc_coherent(host->dev, host->bounce_buf_size, > + &host->bounce_dma_addr, GFP_KERNEL); > + if (host->bounce_buf == NULL) { > + dev_err(host->dev, "Unable to map allocate DMA bounce buffer.\n"); > + ret = -ENOMEM; > + goto err_free_irq; > + } > } > > host->descs = dma_alloc_coherent(host->dev, SD_EMMC_DESC_BUF_LEN, > @@ -1183,8 +1220,9 @@ static int meson_mmc_probe(struct platform_device *pdev) > return 0; > > err_bounce_buf: > - dma_free_coherent(host->dev, host->bounce_buf_size, > - host->bounce_buf, host->bounce_dma_addr); > + if (!host->dram_access_quirk) > + dma_free_coherent(host->dev, host->bounce_buf_size, > + host->bounce_buf, host->bounce_dma_addr); > err_free_irq: > free_irq(host->irq, host); > err_init_clk: > @@ -1208,8 +1246,10 @@ static int meson_mmc_remove(struct platform_device *pdev) > > dma_free_coherent(host->dev, SD_EMMC_DESC_BUF_LEN, > host->descs, host->descs_dma_addr); > - dma_free_coherent(host->dev, host->bounce_buf_size, > - host->bounce_buf, host->bounce_dma_addr); > + > + if (!host->dram_access_quirk) > + dma_free_coherent(host->dev, host->bounce_buf_size, > + host->bounce_buf, host->bounce_dma_addr); > > clk_disable_unprepare(host->mmc_clk); > clk_disable_unprepare(host->core_clk); > -- > 2.21.0 >
diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c index c5a8af4ca76b..bcf1789d26b6 100644 --- a/drivers/mmc/host/meson-gx-mmc.c +++ b/drivers/mmc/host/meson-gx-mmc.c @@ -129,6 +129,9 @@ #define SD_EMMC_TXD 0x94 #define SD_EMMC_LAST_REG SD_EMMC_TXD +#define SD_EMMC_SRAM_DATA_BUF_LEN 1536 +#define SD_EMMC_SRAM_DATA_BUF_OFF 0x200 + #define SD_EMMC_CFG_BLK_SIZE 512 /* internal buffer max: 512 bytes */ #define SD_EMMC_CFG_RESP_TIMEOUT 256 /* in clock cycles */ #define SD_EMMC_CMD_TIMEOUT 1024 /* in ms */ @@ -168,6 +171,8 @@ struct meson_host { unsigned long req_rate; bool ddr; + bool dram_access_quirk; + struct pinctrl *pinctrl; struct pinctrl_state *pins_default; struct pinctrl_state *pins_clk_gate; @@ -232,11 +237,20 @@ static struct mmc_command *meson_mmc_get_next_command(struct mmc_command *cmd) static void meson_mmc_get_transfer_mode(struct mmc_host *mmc, struct mmc_request *mrq) { + struct meson_host *host = mmc_priv(mmc); struct mmc_data *data = mrq->data; struct scatterlist *sg; int i; bool use_desc_chain_mode = true; + /* + * When Controller DMA cannot directly access DDR memory, disable + * support for Chain Mode to directly use the internal SRAM using + * the bounce buffer mode. + */ + if (host->dram_access_quirk) + return; + /* * Broken SDIO with AP6255-based WiFi on Khadas VIM Pro has been * reported. For some strange reason this occurs in descriptor @@ -1049,6 +1063,10 @@ static int meson_mmc_probe(struct platform_device *pdev) host->dev = &pdev->dev; dev_set_drvdata(&pdev->dev, host); + /* The G12A SDIO Controller needs an SRAM bounce buffer */ + host->dram_access_quirk = device_property_read_bool(&pdev->dev, + "amlogic,dram-access-quirk"); + /* Get regulators and the supported OCR mask */ host->vqmmc_enabled = false; ret = mmc_regulator_get_supply(mmc); @@ -1146,9 +1164,16 @@ static int meson_mmc_probe(struct platform_device *pdev) goto err_init_clk; mmc->caps |= MMC_CAP_CMD23; - mmc->max_blk_count = CMD_CFG_LENGTH_MASK; + if (host->dram_access_quirk) { + /* Limit to the available sram memory */ + mmc->max_segs = SD_EMMC_SRAM_DATA_BUF_LEN / mmc->max_blk_size; + mmc->max_blk_count = mmc->max_segs; + } else { + mmc->max_blk_count = CMD_CFG_LENGTH_MASK; + mmc->max_segs = SD_EMMC_DESC_BUF_LEN / + sizeof(struct sd_emmc_desc); + } mmc->max_req_size = mmc->max_blk_count * mmc->max_blk_size; - mmc->max_segs = SD_EMMC_DESC_BUF_LEN / sizeof(struct sd_emmc_desc); mmc->max_seg_size = mmc->max_req_size; /* @@ -1158,15 +1183,27 @@ static int meson_mmc_probe(struct platform_device *pdev) */ mmc->caps2 &= ~MMC_CAP2_HS400; - /* data bounce buffer */ - host->bounce_buf_size = mmc->max_req_size; - host->bounce_buf = - dma_alloc_coherent(host->dev, host->bounce_buf_size, - &host->bounce_dma_addr, GFP_KERNEL); - if (host->bounce_buf == NULL) { - dev_err(host->dev, "Unable to map allocate DMA bounce buffer.\n"); - ret = -ENOMEM; - goto err_free_irq; + if (host->dram_access_quirk) { + /* + * The MMC Controller embeds 1,5KiB of internal SRAM + * that can be used to be used as bounce buffer. + * In the case of the G12A SDIO controller, use these + * instead of the DDR memory + */ + host->bounce_buf_size = SD_EMMC_SRAM_DATA_BUF_LEN; + host->bounce_buf = host->regs + SD_EMMC_SRAM_DATA_BUF_OFF; + host->bounce_dma_addr = res->start + SD_EMMC_SRAM_DATA_BUF_OFF; + } else { + /* data bounce buffer */ + host->bounce_buf_size = mmc->max_req_size; + host->bounce_buf = + dma_alloc_coherent(host->dev, host->bounce_buf_size, + &host->bounce_dma_addr, GFP_KERNEL); + if (host->bounce_buf == NULL) { + dev_err(host->dev, "Unable to map allocate DMA bounce buffer.\n"); + ret = -ENOMEM; + goto err_free_irq; + } } host->descs = dma_alloc_coherent(host->dev, SD_EMMC_DESC_BUF_LEN, @@ -1183,8 +1220,9 @@ static int meson_mmc_probe(struct platform_device *pdev) return 0; err_bounce_buf: - dma_free_coherent(host->dev, host->bounce_buf_size, - host->bounce_buf, host->bounce_dma_addr); + if (!host->dram_access_quirk) + dma_free_coherent(host->dev, host->bounce_buf_size, + host->bounce_buf, host->bounce_dma_addr); err_free_irq: free_irq(host->irq, host); err_init_clk: @@ -1208,8 +1246,10 @@ static int meson_mmc_remove(struct platform_device *pdev) dma_free_coherent(host->dev, SD_EMMC_DESC_BUF_LEN, host->descs, host->descs_dma_addr); - dma_free_coherent(host->dev, host->bounce_buf_size, - host->bounce_buf, host->bounce_dma_addr); + + if (!host->dram_access_quirk) + dma_free_coherent(host->dev, host->bounce_buf_size, + host->bounce_buf, host->bounce_dma_addr); clk_disable_unprepare(host->mmc_clk); clk_disable_unprepare(host->core_clk);