Re: [PATCH v1 1/1] mmc: sdhci-of-dwcmshc: Add CQE support

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Hi

On 2023/8/28 18:34, Sergey Khimich wrote:
Hi Shawn

Thanks for the quick response!

It seems that the patch implemented by  Jyan Chou and my patch are not the same work.There are what we have for both cases:


Yes, however the CEQ part for dw_mmc and for sdhci-of-dwcmshc part is
nearlly the same when I was looking into the databooks of both. 128MB
dma boundary is both stated in the databook, so you need a fix too.

And another issue was found when Rockchip added CQE support for
sdhci-of-dwcmshc internally, is that if a ioctl was issued, cqe_disable
will be called. For CQE of sdhci-of-dwcmshc, the previous in-flight cmd
will be lost quietly. So a mmc->cqe_ops->cqe_wait_for_idle(mmc) should
be added before sdhci_cqe_disable(), so you need a dwcmshc specified
cqe_disable hook in sdhci-of-dwcmshc.

Hope this's helpful for you.

CMDQ implementation by Jyan Chou is for the following sources: drivers/mmc/host/dw_mmc.c and drivers/mmc/host/dw_mmc-pltfm.c. While my patch is for drivers/mmc/host/sdhci-of-dwcmshc.c. And I believe these drivers are not the same. Here what we have in
drivers/mmc/host/dw_mmc-pltfm.c. header:

/*
  * Synopsys DesignWare Multimedia Card Interface driver
  *
  * Copyright (C) 2009 NXP Semiconductors
  * Copyright (C) 2009, 2010 Imagination Technologies Ltd.
  */
and there are "compatible":
         { .compatible = "snps,dw-mshc", },
        { .compatible = "altr,socfpga-dw-mshc", .data = &socfpga_drv_data, },
         { .compatible = "img,pistachio-dw-mshc", },


On the other hand in  drivers/mmc/host/sdhci-of-dwcmshc.c header we have:
/*
  * Driver for Synopsys DesignWare Cores Mobile Storage Host Controller
  *
  * Copyright (C) 2018 Synaptics Incorporated
  *
  * Author: Jisheng Zhang <jszhang@xxxxxxxxxx>
  */

and appropriate "compatible" fields:
         {
                 .compatible = "rockchip,rk3588-dwcmshc",
                 .data = &sdhci_dwcmshc_rk35xx_pdata,
         },
         {
                 .compatible = "rockchip,rk3568-dwcmshc",
                 .data = &sdhci_dwcmshc_rk35xx_pdata,
         },
         {
                 .compatible = "snps,dwcmshc-sdhci",
                 .data = &sdhci_dwcmshc_pdata,
         },


Also thanks for the 128MB DMA boundary issue. But before I start fixing this, could you let me know if there is any point in doing this? Because if I'm wrong in my statement about the difference between Jyan Chou 's patch and my patch and my work is just a duplicate,
then I'd rather not waste my time.

On 28.08.2023 10:48, Shawn Lin wrote:
+Jyan Chou

On 2023/8/25 22:35, Sergey Khimich wrote:
Implement SDHCI CQE support for DesignWare SDHCI.
For enabling CQE support just set 'supports-cqe' in your DevTree file
for appropriate mmc node.


Hi Sergey

Jyan had pushed a version to support it:
https://patchwork.kernel.org/project/linux-mmc/patch/20230616063731.17591-1-jyanchou@xxxxxxxxxxx/

And obviously there are some special limitations from IP vendor
you need to address such as 128MB DMA boundary.

Signed-off-by: Sergey Khimich <serghox@xxxxxxxxx>
---
  drivers/mmc/host/Kconfig            |   1 +
  drivers/mmc/host/sdhci-of-dwcmshc.c | 154 +++++++++++++++++++++++++++-
  2 files changed, 154 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
index 159a3e9490ae..c9fc790d7dba 100644
--- a/drivers/mmc/host/Kconfig
+++ b/drivers/mmc/host/Kconfig
@@ -233,6 +233,7 @@ config MMC_SDHCI_OF_DWCMSHC
      depends on MMC_SDHCI_PLTFM
      depends on OF
      depends on COMMON_CLK
+    select MMC_CQHCI
      help
        This selects Synopsys DesignWare Cores Mobile Storage Controller
        support.
diff --git a/drivers/mmc/host/sdhci-of-dwcmshc.c b/drivers/mmc/host/sdhci-of-dwcmshc.c
index e68cd87998c8..5ee8954a8f5a 100644
--- a/drivers/mmc/host/sdhci-of-dwcmshc.c
+++ b/drivers/mmc/host/sdhci-of-dwcmshc.c
@@ -19,6 +19,7 @@
  #include <linux/sizes.h>
    #include "sdhci-pltfm.h"
+#include "cqhci.h"
    #define SDHCI_DWCMSHC_ARG2_STUFF    GENMASK(31, 16)
  @@ -35,6 +36,9 @@
  #define DWCMSHC_ENHANCED_STROBE        BIT(8)
  #define DWCMSHC_EMMC_ATCTRL        0x40
  +/* DWC IP vendor area 2 pointer */
+#define DWCMSHC_P_VENDOR_AREA2        0xea
+
  /* Rockchip specific Registers */
  #define DWCMSHC_EMMC_DLL_CTRL        0x800
  #define DWCMSHC_EMMC_DLL_RXCLK        0x804
@@ -74,6 +78,10 @@
  #define BOUNDARY_OK(addr, len) \
      ((addr | (SZ_128M - 1)) == ((addr + len - 1) | (SZ_128M - 1)))
  +#define DWCMCHC_SDHCI_CQE_TRNS_MODE    (SDHCI_TRNS_MULTI | \
+                     SDHCI_TRNS_BLK_CNT_EN | \
+                     SDHCI_TRNS_DMA)
+
  enum dwcmshc_rk_type {
      DWCMSHC_RK3568,
      DWCMSHC_RK3588,
@@ -89,7 +97,8 @@ struct rk35xx_priv {
    struct dwcmshc_priv {
      struct clk    *bus_clk;
-    int vendor_specific_area1; /* P_VENDOR_SPECIFIC_AREA reg */
+    int vendor_specific_area1; /* P_VENDOR_SPECIFIC_AREA1 reg */
+    int vendor_specific_area2; /* P_VENDOR_SPECIFIC_AREA2 reg */
      void *priv; /* pointer to SoC private stuff */
  };
  @@ -209,6 +218,65 @@ static void dwcmshc_hs400_enhanced_strobe(struct mmc_host *mmc,
      sdhci_writel(host, vendor, reg);
  }
  +static u32 dwcmshc_cqe_irq_handler(struct sdhci_host *host, u32 intmask)
+{
+    int cmd_error = 0;
+    int data_error = 0;
+
+    if (!sdhci_cqe_irq(host, intmask, &cmd_error, &data_error))
+        return intmask;
+
+    cqhci_irq(host->mmc, intmask, cmd_error, data_error);
+
+    return 0;
+}
+
+static void dwcmshc_sdhci_cqe_enable(struct mmc_host *mmc)
+{
+    struct sdhci_host *host = mmc_priv(mmc);
+    u32 pstate;
+    u8 ctrl;
+    int count = 10;
+
+    /*
+     * CQE gets stuck if it sees Buffer Read Enable bit set, which can be
+     * the case after tuning, so ensure the buffer is drained.
+     */
+    pstate = sdhci_readl(host, SDHCI_PRESENT_STATE);
+    while (pstate & SDHCI_DATA_AVAILABLE) {
+        sdhci_readl(host, SDHCI_BUFFER);
+        pstate = sdhci_readl(host, SDHCI_PRESENT_STATE);
+        if (count-- == 0) {
+            dev_warn(mmc_dev(host->mmc),
+                 "CQE may get stuck because the Buffer Read Enable bit is set\n");
+            break;
+        }
+        mdelay(1);
+    }
+
+    sdhci_writew(host, DWCMCHC_SDHCI_CQE_TRNS_MODE, SDHCI_TRANSFER_MODE);
+
+    sdhci_cqe_enable(mmc);
+
+    /*
+     * The "DesignWare Cores Mobile Storage Host Controller
+     * DWC_mshc / DWC_mshc_lite Databook" says:
+     * when Host Version 4 Enable" is 1 in Host Control 2 register,
+     * SDHCI_CTRL_ADMA32 bit means ADMA2 is selected.
+     * Selection of 32-bit/64-bit System Addressing:
+     * either 32-bit or 64-bit system addressing is selected by
+     * 64-bit Addressing bit in Host Control 2 register.
+     *
+     * On the other hand the "DesignWare Cores Mobile Storage Host
+     * Controller DWC_mshc / DWC_mshc_lite User Guide" says, that we have to
+     * set DMA_SEL to ADMA2 _only_ mode in the Host Control 2 register.
+     */
+    ctrl = sdhci_readb(host, SDHCI_HOST_CONTROL);
+    ctrl &= ~SDHCI_CTRL_DMA_MASK;
+    ctrl |= SDHCI_CTRL_ADMA32;
+    sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
+}
+
  static void dwcmshc_rk3568_set_clock(struct sdhci_host *host, unsigned int clock)
  {
      struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
@@ -344,6 +412,7 @@ static const struct sdhci_ops sdhci_dwcmshc_ops = {
      .get_max_clock        = dwcmshc_get_max_clock,
      .reset            = sdhci_reset,
      .adma_write_desc    = dwcmshc_adma_write_desc,
+    .irq            = dwcmshc_cqe_irq_handler,
  };
    static const struct sdhci_ops sdhci_dwcmshc_rk35xx_ops = {
@@ -378,6 +447,74 @@ static const struct sdhci_pltfm_data sdhci_dwcmshc_rk35xx_pdata = {
             SDHCI_QUIRK2_CLOCK_DIV_ZERO_BROKEN,
  };
  +static void dwcmshc_cqhci_dumpregs(struct mmc_host *mmc)
+{
+    sdhci_dumpregs(mmc_priv(mmc));
+}
+
+static const struct cqhci_host_ops dwcmshc_cqhci_ops = {
+    .enable        = dwcmshc_sdhci_cqe_enable,
+    .disable    = sdhci_cqe_disable,
+    .dumpregs    = dwcmshc_cqhci_dumpregs,
+};
+
+static void dwcmshc_cqhci_init(struct sdhci_host *host, struct platform_device *pdev)
+{
+    struct cqhci_host *cq_host;
+    struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+    struct dwcmshc_priv *priv = sdhci_pltfm_priv(pltfm_host);
+    bool dma64 = false;
+    u16 clk;
+    int err;
+
+    host->mmc->caps2 |= MMC_CAP2_CQE | MMC_CAP2_CQE_DCMD;
+    cq_host = devm_kzalloc(&pdev->dev, sizeof(*cq_host), GFP_KERNEL);
+    if (!cq_host) {
+        dev_err(mmc_dev(host->mmc), "Unable to setup CQE: not enough memory\n");
+        return;
+    }
+
+    /*
+     * For dwcmshc host controller we have to enable internal clock
+     * before access to some registers from Vendor Specific Aria 2.
+     */
+    clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
+    clk |= SDHCI_CLOCK_INT_EN;
+    sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
+    clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
+    if (!(clk & SDHCI_CLOCK_INT_EN)) {
+        dev_err(mmc_dev(host->mmc), "Unable to setup CQE: internal clock enable error\n");
+        goto free_cq_host;
+    }
+
+    cq_host->mmio = host->ioaddr + priv->vendor_specific_area2;
+    cq_host->ops = &dwcmshc_cqhci_ops;
+
+    /* Enable using of 128-bit task descriptors */
+    dma64 = host->flags & SDHCI_USE_64_BIT_DMA;
+    if (dma64) {
+        dev_dbg(mmc_dev(host->mmc), "128-bit task descriptors\n");
+        cq_host->caps |= CQHCI_TASK_DESC_SZ_128;
+    }
+    err = cqhci_init(cq_host, host->mmc, dma64);
+    if (err) {
+        dev_err(mmc_dev(host->mmc), "Unable to setup CQE: error %d\n", err);
+        goto int_clok_disable;
+    }
+
+    dev_dbg(mmc_dev(host->mmc), "CQE init done\n");
+
+    return;
+
+int_clok_disable:
+    clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
+    clk &= ~SDHCI_CLOCK_INT_EN;
+    sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
+
+free_cq_host:
+    devm_kfree(&pdev->dev, cq_host);
+}
+
  static int dwcmshc_rk35xx_init(struct sdhci_host *host, struct dwcmshc_priv *dwc_priv)
  {
      int err;
@@ -471,6 +608,7 @@ static int dwcmshc_probe(struct platform_device *pdev)
      const struct sdhci_pltfm_data *pltfm_data;
      int err;
      u32 extra;
+    u32 caps;
        pltfm_data = device_get_match_data(&pdev->dev);
      if (!pltfm_data) {
@@ -518,6 +656,8 @@ static int dwcmshc_probe(struct platform_device *pdev)
        priv->vendor_specific_area1 =
          sdhci_readl(host, DWCMSHC_P_VENDOR_AREA1) & DWCMSHC_AREA1_MASK;
+    priv->vendor_specific_area2 =
+        sdhci_readw(host, DWCMSHC_P_VENDOR_AREA2);
        host->mmc_host_ops.request = dwcmshc_request;
      host->mmc_host_ops.hs400_enhanced_strobe = dwcmshc_hs400_enhanced_strobe; @@ -546,12 +686,24 @@ static int dwcmshc_probe(struct platform_device *pdev)
          sdhci_enable_v4_mode(host);
  #endif
  +    caps = sdhci_readl(host, SDHCI_CAPABILITIES);
+    if (caps & SDHCI_CAN_64BIT_V4)
+        sdhci_enable_v4_mode(host);
+
      host->mmc->caps |= MMC_CAP_WAIT_WHILE_BUSY;
        err = sdhci_setup_host(host);
      if (err)
          goto err_clk;
  +    /* Setup Command Queue Engine if enabled */
+    if (device_property_read_bool(&pdev->dev, "supports-cqe")) {
+        if (caps & SDHCI_CAN_64BIT_V4)
+            dwcmshc_cqhci_init(host, pdev);
+        else
+            dev_warn(dev, "Cannot enable CQE without V4 mode support\n");
+    }
+
      if (rk_priv)
          dwcmshc_rk35xx_postinit(host, priv);



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