[PATCH v3 0/2] CQE support for cadence eMMC host controller

[PATCH v3 0/2] CQE support for cadence eMMC host controller

[Rohan Joshi via B4 Relay]

Hi,

This series adds CQE (Command Queue Engine) support for cadence
eMMC host controller. the driver enables CQE when both the
conditions mentioned below are met
        1. Hardware reports the presence of CQE
        2. DT provides a "cqhci" register space

The driver handles amd,pensando-elba platform separately
since it requires an additional byte-lane control
register space. The space is mapped via index "1".
The cqhci-core function "cqhci_pltfm_init" maps CQE
via a named resource "cqchi" and hence DT needs to define
the same if the CQE needs to be enabled

The patch adds three named resources to cater for the
above mentioned requirement. It creates the two possible
combinations for amd,pensando-elba platform,
        [hc, bctl] or [hc, bctl, cqhci]
and the other platforms,
        [hc] or [hc, cqhci]

Signed-off-by: Rohan Joshi <rohan1sj@cadence.com>
---
Changes in v3:
- Device Tree updates to account for multiple platforms supporting CQE
- Link to v2: https://patch.msgid.link/20260506-cdns_sdhci_cqe-support-v2-0-754fe4de8b65@cadence.com

Changes in v2:
- Use dev_err_probe() for error messages when in probe path
- Updated commit messages as per subsystem naming conventions
- Select MMC_CQHCI in Kconfig for MMC_SDHCI_CADENCE
- Drop new dt-binding example and corrected existing one
- Link to v1: https://patch.msgid.link/20260407-cdns_sdhci_cqe-support-v1-0-13efc0810631@cadence.com

---
Rohan Joshi (2):
      dt-bindings: mmc: cdns,sdhci: Add CQE support
      mmc: sdhci-cadence: add CQE support

 .../devicetree/bindings/mmc/cdns,sdhci.yaml        |  28 ++++-
 drivers/mmc/host/Kconfig                           |   1 +
 drivers/mmc/host/sdhci-cadence.c                   | 124 ++++++++++++++++++++-
 3 files changed, 146 insertions(+), 7 deletions(-)
---
base-commit: 1590cf0329716306e948a8fc29f1d3ee87d3989f
change-id: 20260721-cdns_sdhci_cqe-support-bf4e4dfcfe67

Best regards,
-- 
Rohan Joshi <rohan1sj@cadence.com>

[PATCH v3 1/2] dt-bindings: mmc: cdns,sdhci: Add CQE support

[Rohan Joshi via B4 Relay]

From: Rohan Joshi <rohan1sj@cadence.com>

Cadence host controller can optionally support CQE.
Add optional CQE register space to cdns sdhci bindings.

Signed-off-by: Rohan Joshi <rohan1sj@cadence.com>
---
 .../devicetree/bindings/mmc/cdns,sdhci.yaml        | 28 +++++++++++++++++++---
 1 file changed, 25 insertions(+), 3 deletions(-)

diff --git a/Documentation/devicetree/bindings/mmc/cdns,sdhci.yaml b/Documentation/devicetree/bindings/mmc/cdns,sdhci.yaml
index 6c7317d13aa6..10bc9ac2073a 100644
--- a/Documentation/devicetree/bindings/mmc/cdns,sdhci.yaml
+++ b/Documentation/devicetree/bindings/mmc/cdns,sdhci.yaml
@@ -22,7 +22,14 @@ properties:
 
   reg:
     minItems: 1
-    maxItems: 2
+    maxItems: 3
+
+  reg-names:
+    minItems: 1
+    items:
+      - const: hc
+      - enum: [bctl, cqhci]
+      - const: cqhci
 
   interrupts:
     maxItems: 1
@@ -131,13 +138,27 @@ allOf:
     then:
       properties:
         reg:
+          minItems: 2
           items:
             - description: Host controller registers
             - description: Elba byte-lane enable register for writes
+            - description: CQE (Command Queuing Engine) registers (optional)
+        reg-names:
+          minItems: 2
+          items:
+            - const: hc
+            - const: bctl
+            - const: cqhci
     else:
       properties:
         reg:
-          maxItems: 1
+          items:
+            - description: Host Controller registers
+            - description: CQE (Command Queuing Engine) registers (optional)
+        reg-names:
+          items:
+            - const: hc
+            - const: cqhci
 
 unevaluatedProperties: false
 
@@ -145,7 +166,8 @@ examples:
   - |
     emmc: mmc@5a000000 {
         compatible = "socionext,uniphier-sd4hc", "cdns,sd4hc";
-        reg = <0x5a000000 0x400>;
+        reg = <0x5a000000 0x400>, <0x5a000400 0x060>;
+        reg-names = "hc", "cqhci";
         interrupts = <0 78 4>;
         clocks = <&clk 4>;
         bus-width = <8>;

-- 
2.43.0

Re: [PATCH v3 1/2] dt-bindings: mmc: cdns,sdhci: Add CQE support

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] Missing `maxItems: 2` constraint in the `else` block allows invalid device tree configurations to pass validation.
--

--- Patch [1]: [PATCH v3 1/2] dt-bindings: mmc: cdns,sdhci: Add CQE support ---
commit deaf7bf4553d7883c61e62fdcaba11a90405564f
Author: Rohan Joshi <rohan1sj@cadence.com>

dt-bindings: mmc: cdns,sdhci: Add CQE support

This commit adds optional Command Queuing Engine (CQE) register space to the 
Cadence SDHCI bindings. It expands the top-level reg constraints to allow up
to 3 items and adjusts the allOf conditionals for Elba and non-Elba variants.

> diff --git a/Documentation/devicetree/bindings/mmc/cdns,sdhci.yaml b/Documentation/devicetree/bindings/mmc/cdns,sdhci.yaml
> index 6c7317d13aa6c..10bc9ac2073a6 100644
> --- a/Documentation/devicetree/bindings/mmc/cdns,sdhci.yaml
> +++ b/Documentation/devicetree/bindings/mmc/cdns,sdhci.yaml

[ ... ]

> @@ -131,13 +138,27 @@ allOf:
>      then:
>        properties:
>          reg:
> +          minItems: 2
>            items:
>              - description: Host controller registers
>              - description: Elba byte-lane enable register for writes
> +            - description: CQE (Command Queuing Engine) registers (optional)
> +        reg-names:
> +          minItems: 2
> +          items:
> +            - const: hc
> +            - const: bctl
> +            - const: cqhci
>      else:
>        properties:
>          reg:
> -          maxItems: 1
> +          items:
> +            - description: Host Controller registers
> +            - description: CQE (Command Queuing Engine) registers (optional)

[Severity: Low]
Does this else block need an explicit maxItems: 2 for reg and reg-names?

Since the top-level property now allows up to 3 items, and dtschema does
not automatically apply maxItems bounds from items lists inside
conditional blocks, could a non-Elba device tree incorrectly define 3
registers and still pass validation?

> +        reg-names:
> +          items:
> +            - const: hc
> +            - const: cqhci

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260722-cdns_sdhci_cqe-support-v3-0-4412856a4488@cadence.com?part=1

Re: [PATCH v3 1/2] dt-bindings: mmc: cdns,sdhci: Add CQE support

[Conor Dooley]

[-- Attachment #1: Type: text/plain, Size: 2553 bytes --]

On Wed, Jul 22, 2026 at 04:18:37PM +0530, Rohan Joshi via B4 Relay wrote:
> From: Rohan Joshi <rohan1sj@cadence.com>
> 
> Cadence host controller can optionally support CQE.
> Add optional CQE register space to cdns sdhci bindings.
> 
> Signed-off-by: Rohan Joshi <rohan1sj@cadence.com>
> ---
>  .../devicetree/bindings/mmc/cdns,sdhci.yaml        | 28 +++++++++++++++++++---
>  1 file changed, 25 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/mmc/cdns,sdhci.yaml b/Documentation/devicetree/bindings/mmc/cdns,sdhci.yaml
> index 6c7317d13aa6..10bc9ac2073a 100644
> --- a/Documentation/devicetree/bindings/mmc/cdns,sdhci.yaml
> +++ b/Documentation/devicetree/bindings/mmc/cdns,sdhci.yaml
> @@ -22,7 +22,14 @@ properties:
>  
>    reg:
>      minItems: 1
> -    maxItems: 2
> +    maxItems: 3
> +
> +  reg-names:
> +    minItems: 1
> +    items:
> +      - const: hc
> +      - enum: [bctl, cqhci]
> +      - const: cqhci
>  
>    interrupts:
>      maxItems: 1
> @@ -131,13 +138,27 @@ allOf:
>      then:
>        properties:
>          reg:
> +          minItems: 2
>            items:
>              - description: Host controller registers
>              - description: Elba byte-lane enable register for writes
> +            - description: CQE (Command Queuing Engine) registers (optional)

I see no explanation in your commit message for why the elba is being
modified.

This new reg entry should be restricted to only the device-specific
compatibles that actually support it.

pw-bot: changes-requested

Thanks,
Conor.

> +        reg-names:
> +          minItems: 2
> +          items:
> +            - const: hc
> +            - const: bctl
> +            - const: cqhci
>      else:
>        properties:
>          reg:
> -          maxItems: 1
> +          items:
> +            - description: Host Controller registers
> +            - description: CQE (Command Queuing Engine) registers (optional)
> +        reg-names:
> +          items:
> +            - const: hc
> +            - const: cqhci
>  
>  unevaluatedProperties: false
>  
> @@ -145,7 +166,8 @@ examples:
>    - |
>      emmc: mmc@5a000000 {
>          compatible = "socionext,uniphier-sd4hc", "cdns,sd4hc";
> -        reg = <0x5a000000 0x400>;
> +        reg = <0x5a000000 0x400>, <0x5a000400 0x060>;
> +        reg-names = "hc", "cqhci";
>          interrupts = <0 78 4>;
>          clocks = <&clk 4>;
>          bus-width = <8>;
> 
> -- 
> 2.43.0
> 
> 

[-- Attachment #2: signature.asc --]
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[PATCH v3 2/2] mmc: sdhci-cadence: add CQE support

[Rohan Joshi via B4 Relay]

From: Rohan Joshi <rohan1sj@cadence.com>

Cadence host controller has optional CQE (Command Queue Engine).
The presence of CQE is determined by an additional host capability
register. The same information is used to identify and support all
platforms that contain Command Queue Engine

Signed-off-by: Rohan Joshi <rohan1sj@cadence.com>
---
 drivers/mmc/host/Kconfig         |   1 +
 drivers/mmc/host/sdhci-cadence.c | 124 +++++++++++++++++++++++++++++++++++++--
 2 files changed, 121 insertions(+), 4 deletions(-)

diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
index 4f060d3e5636..2cc8133e8ef3 100644
--- a/drivers/mmc/host/Kconfig
+++ b/drivers/mmc/host/Kconfig
@@ -293,6 +293,7 @@ config MMC_SDHCI_CADENCE
 	depends on MMC_SDHCI_PLTFM
 	depends on OF
 	select MMC_SDHCI_IO_ACCESSORS
+	select MMC_CQHCI
 	help
 	  This selects the Cadence SD/SDIO/eMMC driver.
 
diff --git a/drivers/mmc/host/sdhci-cadence.c b/drivers/mmc/host/sdhci-cadence.c
index 435603c8c00b..f1ae7743ef5f 100644
--- a/drivers/mmc/host/sdhci-cadence.c
+++ b/drivers/mmc/host/sdhci-cadence.c
@@ -15,6 +15,8 @@
 #include <linux/reset.h>
 
 #include "sdhci-pltfm.h"
+#include "sdhci-cqhci.h"
+#include "cqhci.h"
 
 /* HRS - Host Register Set (specific to Cadence) */
 #define SDHCI_CDNS_HRS04		0x10		/* PHY access port */
@@ -36,6 +38,10 @@
 #define   SDHCI_CDNS_HRS06_MODE_MMC_HS400	0x5
 #define   SDHCI_CDNS_HRS06_MODE_MMC_HS400ES	0x6
 
+/* Host capabilities not covered by the standard capability registers (SRS16-SRS18) */
+#define SDHCI_CDNS_HRS30		0x78	/* Host capabilities */
+#define SDHCI_CDNS_HRS30_CQE_SUPPORTED	BIT(0)
+
 /* Read block gap */
 #define SDHCI_CDNS_HRS37		0x94	/* interface mode select */
 #define   SDHCI_CDNS_HRS37_MODE_DS		0x0
@@ -88,6 +94,7 @@ struct sdhci_cdns_priv {
 	void __iomem *ctl_addr;	/* write control */
 	spinlock_t wrlock;	/* write lock */
 	bool enhanced_strobe;
+	bool cqe_support;	/* Command Queuing Engine support */
 	void (*priv_writel)(struct sdhci_cdns_priv *priv, u32 val, void __iomem *reg);
 	struct reset_control *rst_hw;
 	unsigned int nr_phy_params;
@@ -385,6 +392,68 @@ static void sdhci_cdns_set_uhs_signaling(struct sdhci_host *host,
 		sdhci_set_uhs_signaling(host, timing);
 }
 
+static u32 sdhci_cdns_cqhci_irq(struct sdhci_host *host, u32 intmask)
+{
+	int cmd_err = 0;
+	int data_err = 0;
+
+	/* return original intmask to be handled by other handlers if it's not a CQE interrupt */
+	if (!sdhci_cqe_irq(host, intmask, &cmd_err, &data_err))
+		return intmask;
+
+	cqhci_irq(host->mmc, intmask, cmd_err, data_err);
+
+	return 0;
+}
+
+static const struct cqhci_host_ops sdhci_cdns_cqhci_ops = {
+	.enable		= sdhci_cqe_enable,
+	.disable	= sdhci_cqe_disable,
+};
+
+static int sdhci_cdns_cqe_add_host(struct sdhci_host *host, struct platform_device *pdev)
+{
+	struct cqhci_host *cq_host;
+	bool dma64;
+	int ret;
+
+	ret = sdhci_setup_host(host);
+	if (ret)
+		return ret;
+
+	cq_host = cqhci_pltfm_init(pdev);
+	if (IS_ERR(cq_host)) {
+		ret = PTR_ERR(cq_host);
+		dev_err_probe(&pdev->dev, ret, "cqhci platform init failed\n");
+		goto cleanup;
+	}
+
+	dma64 = host->flags & SDHCI_USE_64_BIT_DMA;
+	if (dma64)
+		cq_host->caps |= CQHCI_TASK_DESC_SZ_128;
+
+	cq_host->ops = &sdhci_cdns_cqhci_ops;
+
+	host->mmc->caps2 |= MMC_CAP2_CQE | MMC_CAP2_CQE_DCMD;
+
+	ret = cqhci_init(cq_host, host->mmc, dma64);
+	if (ret) {
+		dev_err_probe(&pdev->dev, ret, "cqhci init failed\n");
+		goto cleanup;
+	}
+
+	/* add host to MMC subsystem */
+	ret = __sdhci_add_host(host);
+	if (ret)
+		goto cleanup;
+
+	return 0;
+
+cleanup:
+	sdhci_cleanup_host(host);
+	return ret;
+}
+
 /* Elba control register bits [6:3] are byte-lane enables */
 #define ELBA_BYTE_ENABLE_MASK(x)	((x) << 3)
 
@@ -445,8 +514,9 @@ static const struct sdhci_ops sdhci_elba_ops = {
 	.set_clock = sdhci_set_clock,
 	.get_timeout_clock = sdhci_cdns_get_timeout_clock,
 	.set_bus_width = sdhci_set_bus_width,
-	.reset = sdhci_reset,
+	.reset = sdhci_and_cqhci_reset,
 	.set_uhs_signaling = sdhci_cdns_set_uhs_signaling,
+	.irq = sdhci_cdns_cqhci_irq,
 };
 
 static int elba_drv_init(struct platform_device *pdev)
@@ -474,9 +544,10 @@ static const struct sdhci_ops sdhci_cdns_ops = {
 	.set_clock = sdhci_set_clock,
 	.get_timeout_clock = sdhci_cdns_get_timeout_clock,
 	.set_bus_width = sdhci_set_bus_width,
-	.reset = sdhci_reset,
+	.reset = sdhci_and_cqhci_reset,
 	.platform_execute_tuning = sdhci_cdns_execute_tuning,
 	.set_uhs_signaling = sdhci_cdns_set_uhs_signaling,
+	.irq = sdhci_cdns_cqhci_irq,
 };
 
 static const struct sdhci_cdns_drv_data sdhci_cdns_uniphier_drv_data = {
@@ -553,6 +624,8 @@ static int sdhci_cdns_probe(struct platform_device *pdev)
 	int ret;
 	struct device *dev = &pdev->dev;
 	static const u16 version = SDHCI_SPEC_400 << SDHCI_SPEC_VER_SHIFT;
+	bool cqe_enabled;
+	u32 host_caps;
 
 	clk = devm_clk_get_enabled(dev, NULL);
 	if (IS_ERR(clk))
@@ -608,7 +681,43 @@ static int sdhci_cdns_probe(struct platform_device *pdev)
 			host->mmc_host_ops.card_hw_reset = sdhci_cdns_mmc_hw_reset;
 	}
 
-	return sdhci_add_host(host);
+	host_caps = readl(priv->hrs_addr + SDHCI_CDNS_HRS30);
+
+	/*
+	 * CQE is enabled only when both conditions are met:
+	 *   1. Hardware reports CQE support via HRS30[0].
+	 *   2. DT provides a named "cqhci" register space.
+	 */
+	cqe_enabled = (host_caps & SDHCI_CDNS_HRS30_CQE_SUPPORTED) &&
+		      !!platform_get_resource_byname(pdev, IORESOURCE_MEM, "cqhci");
+
+	if ((host_caps & SDHCI_CDNS_HRS30_CQE_SUPPORTED) && !cqe_enabled)
+		dev_dbg(dev, "CQE supported by hardware but no 'cqhci' register space in DT, disabling\n");
+
+	if (cqe_enabled) {
+		priv->cqe_support = true;
+		ret = sdhci_cdns_cqe_add_host(host, pdev);
+	} else {
+		ret = sdhci_add_host(host);
+	}
+
+	return ret;
+}
+
+static int sdhci_cdns_suspend(struct device *dev)
+{
+	struct sdhci_host *host = dev_get_drvdata(dev);
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct sdhci_cdns_priv *priv = sdhci_pltfm_priv(pltfm_host);
+	int ret;
+
+	if (priv->cqe_support) {
+		ret = cqhci_suspend(host->mmc);
+		if (ret)
+			return ret;
+	}
+
+	return sdhci_pltfm_suspend(dev);
 }
 
 static int sdhci_cdns_resume(struct device *dev)
@@ -630,6 +739,13 @@ static int sdhci_cdns_resume(struct device *dev)
 	if (ret)
 		goto disable_clk;
 
+	/* Resume CQE if enabled */
+	if (priv->cqe_support) {
+		ret = cqhci_resume(host->mmc);
+		if (ret)
+			goto disable_clk;
+	}
+
 	return 0;
 
 disable_clk:
@@ -638,7 +754,7 @@ static int sdhci_cdns_resume(struct device *dev)
 	return ret;
 }
 
-static DEFINE_SIMPLE_DEV_PM_OPS(sdhci_cdns_pm_ops, sdhci_pltfm_suspend, sdhci_cdns_resume);
+static DEFINE_SIMPLE_DEV_PM_OPS(sdhci_cdns_pm_ops, sdhci_cdns_suspend, sdhci_cdns_resume);
 
 static const struct of_device_id sdhci_cdns_match[] = {
 	{

-- 
2.43.0

Re: [PATCH v3 2/2] mmc: sdhci-cadence: add CQE support

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] In `sdhci_cdns_resume()`, if `cqhci_resume()` were to fail, the error path fails to roll back the already-resumed SDHCI host.
--

--- Patch [2]: [PATCH v3 2/2] mmc: sdhci-cadence: add CQE support ---
commit 3bdb7a0ff9ae82cc040dd069fa74bd0366328e92
Author: Rohan Joshi <rohan1sj@cadence.com>

mmc: sdhci-cadence: add CQE support

This commit adds optional Command Queue Engine (CQE) support to the Cadence
SDHCI host controller driver. The presence of CQE is determined by an
additional host capability register and integrated into the host setup.

> diff --git a/drivers/mmc/host/sdhci-cadence.c b/drivers/mmc/host/sdhci-cadence.c
> --- a/drivers/mmc/host/sdhci-cadence.c
> +++ b/drivers/mmc/host/sdhci-cadence.c

[ ... ]

> @@ -630,6 +739,13 @@ static int sdhci_cdns_resume(struct device *dev)
>  	ret = sdhci_resume_host(host);
>  	if (ret)
>  		goto disable_clk;
>  
> +	/* Resume CQE if enabled */
> +	if (priv->cqe_support) {
> +		ret = cqhci_resume(host->mmc);
> +		if (ret)
> +			goto disable_clk;
> +	}
> +
>  	return 0;
>  
>  disable_clk:
>  	clk_disable_unprepare(pltfm_host->clk);
>  
>  	return ret;
>  }

[Severity: Low]
If cqhci_resume() fails, the code jumps to disable_clk, which disables the
clock but leaves the SDHCI host in a resumed state since sdhci_resume_host()
was already called successfully. Is it intentional to skip rolling back the
host resume here?

While cqhci_resume() unconditionally returns 0 today, making this error
path structurally impossible to execute at the moment, should this perhaps
call sdhci_suspend_host() on error to keep the power management state
balanced in case cqhci_resume() behavior changes in the future?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260722-cdns_sdhci_cqe-support-v3-0-4412856a4488@cadence.com?part=2