[PATCH v2 0/2] mmc: sdhci-of-dwcmshc: Add CQE support

[PATCH v2 0/2] mmc: sdhci-of-dwcmshc: Add CQE support

[Sergey Khimich]

Hello!

This is implementation of SDHCI CQE support for sdhci-of-dwcmshc driver.
For enabling CQE support just set 'supports-cqe' in your DevTree file
for appropriate mmc node.

Also, while implementing CQE support for the driver, I faced with a problem 
which I will describe below.
According to the IP block documentation CQE works only with "AMDA-2 only"
mode which is activated only with v4 mode enabled. I see in dwcmshc_probe()
function that v4 mode gets enabled only for 'sdhci_dwcmshc_bf3_pdata' platform data.

So my question is: is it correct to enable v4 mode for all platform data
if 'SDHCI_CAN_64BIT_V4' bit is set in hw?

Because I`m afraid that enabling v4 mode for some platforms could break
them down. On the other hand, if host controller says that it can do v4
(caps & SDHCI_CAN_64BIT_V4), lets do v4 or disable it manualy by some
quirk. Anyway - RFC.


v2:
 - Added dwcmshc specific cqe_disable hook to prevent losing
   in-flight cmd when an ioctl is issued and cqe_disable is called;

 - Added processing 128Mb boundary for the host memory data buffer size
   and the data buffer. For implementing this processing an extra
   callback is added to the struct 'sdhci_ops'.

 - Fixed typo.


Thanks in advance, Sergey.


Sergey Khimich (2):
  mmc: cqhci: Add cqhci_set_tran_desc() callback
  Implement SDHCI CQE support for DesignWare SDHCI.

 drivers/mmc/host/Kconfig            |   1 +
 drivers/mmc/host/cqhci-core.c       |   5 +
 drivers/mmc/host/cqhci.h            |   3 +
 drivers/mmc/host/sdhci-of-dwcmshc.c | 233 +++++++++++++++++++++++++++-
 4 files changed, 240 insertions(+), 2 deletions(-)

-- 
2.30.2

[PATCH v2 1/2] mmc: cqhci: Add cqhci_set_tran_desc() callback

[Sergey Khimich]

From: Sergey Khimich <serghox@gmail.com>

There are could be specific limitations for some mmc
controllers for preparing and setting cqhci transfer
descriptors. So add callback to allow implement
driver specific function.

Signed-off-by: Sergey Khimich <serghox@gmail.com>
---
 drivers/mmc/host/cqhci-core.c | 5 +++++
 drivers/mmc/host/cqhci.h      | 3 +++
 2 files changed, 8 insertions(+)

diff --git a/drivers/mmc/host/cqhci-core.c b/drivers/mmc/host/cqhci-core.c
index b3d7d6d8d654..22be6b0b32ca 100644
--- a/drivers/mmc/host/cqhci-core.c
+++ b/drivers/mmc/host/cqhci-core.c
@@ -516,6 +516,11 @@ static int cqhci_prep_tran_desc(struct mmc_request *mrq,
 
 	desc = get_trans_desc(cq_host, tag);
 
+	if (cq_host->ops->prep_tran_desc) {
+		cq_host->ops->prep_tran_desc(data, cq_host, desc, sg_count);
+		return 0;
+	}
+
 	for_each_sg(data->sg, sg, sg_count, i) {
 		addr = sg_dma_address(sg);
 		len = sg_dma_len(sg);
diff --git a/drivers/mmc/host/cqhci.h b/drivers/mmc/host/cqhci.h
index 1a12e40a02e6..c473d8994ca4 100644
--- a/drivers/mmc/host/cqhci.h
+++ b/drivers/mmc/host/cqhci.h
@@ -293,6 +293,9 @@ struct cqhci_host_ops {
 	int (*program_key)(struct cqhci_host *cq_host,
 			   const union cqhci_crypto_cfg_entry *cfg, int slot);
 #endif
+	void (*prep_tran_desc)(struct mmc_data *data, struct cqhci_host *cq_host,
+			       u8 *desc, int sg_count);
+
 };
 
 static inline void cqhci_writel(struct cqhci_host *host, u32 val, int reg)
-- 
2.30.2

[PATCH v2 2/2] Implement SDHCI CQE support for DesignWare SDHCI.

[Sergey Khimich]

From: Sergey Khimich <serghox@gmail.com>

For enabling CQE support just set 'supports-cqe' in your DevTree file
for appropriate mmc node.

Signed-off-by: Sergey Khimich <serghox@gmail.com>
---
 drivers/mmc/host/Kconfig            |   1 +
 drivers/mmc/host/sdhci-of-dwcmshc.c | 233 +++++++++++++++++++++++++++-
 2 files changed, 232 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
index 554e67103c1a..f3380b014ca9 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 3a3bae6948a8..7d43ae011811 100644
--- a/drivers/mmc/host/sdhci-of-dwcmshc.c
+++ b/drivers/mmc/host/sdhci-of-dwcmshc.c
@@ -20,6 +20,7 @@
 #include <linux/sizes.h>
 
 #include "sdhci-pltfm.h"
+#include "cqhci.h"
 
 #define SDHCI_DWCMSHC_ARG2_STUFF	GENMASK(31, 16)
 
@@ -36,6 +37,9 @@
 #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
@@ -75,6 +79,10 @@
 #define BOUNDARY_OK(addr, len) \
 	((addr | (SZ_128M - 1)) == ((addr + len - 1) | (SZ_128M - 1)))
 
+#define DWCMSHC_SDHCI_CQE_TRNS_MODE	(SDHCI_TRNS_MULTI | \
+					 SDHCI_TRNS_BLK_CNT_EN | \
+					 SDHCI_TRNS_DMA)
+
 enum dwcmshc_rk_type {
 	DWCMSHC_RK3568,
 	DWCMSHC_RK3588,
@@ -90,7 +98,8 @@ 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 */
 };
 
@@ -210,6 +219,147 @@ 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, DWCMSHC_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_sdhci_cqe_disable(struct mmc_host *mmc, bool recovery)
+{
+	/*
+	 * If an ioctl was issued, cqe_disable will be called.
+	 * For CQE of sdhci-of-dwcmshc, the previous in-flight cmd will be lost quietly.
+	 * So wait for mmc idle state.
+	 */
+	mmc->cqe_ops->cqe_wait_for_idle(mmc);
+
+	return sdhci_cqe_disable(mmc, recovery);
+}
+
+static void dwcmshc_cqhci_set_tran_desc(u8 *desc, dma_addr_t addr, int len, bool end,
+					bool dma64)
+{
+	__le32 *attr = (__le32 __force *)desc;
+
+	*attr = (CQHCI_VALID(1) |
+		 CQHCI_END(end ? 1 : 0) |
+		 CQHCI_INT(0) |
+		 CQHCI_ACT(0x4) |
+		 CQHCI_DAT_LENGTH(len));
+
+	if (dma64) {
+		__le64 *dataddr = (__le64 __force *)(desc + 4);
+
+		dataddr[0] = cpu_to_le64(addr);
+	} else {
+		__le32 *dataddr = (__le32 __force *)(desc + 4);
+
+		dataddr[0] = cpu_to_le32(addr);
+	}
+}
+
+static void dwcmshc_cqhci_prep_tran_desc(struct mmc_data *data,
+					 struct cqhci_host *cq_host,
+					 u8 *desc, int sg_count)
+{
+	int i, len, tmplen, offset;
+	bool end = false;
+	bool dma64 = cq_host->dma64;
+	dma_addr_t addr;
+	struct scatterlist *sg;
+
+	for_each_sg(data->sg, sg, sg_count, i) {
+		addr = sg_dma_address(sg);
+		len = sg_dma_len(sg);
+
+		/*
+		 * According to the "DesignWare Cores Mobile Storage Host Controller
+		 * DWC_mshc / DWC_mshc_lite Databook" the host memory data buffer size
+		 * and start address must not exceed 128 Mb. If it exceeds,
+		 * the data buffer must be split using two descritors.
+		 */
+
+		if (likely(BOUNDARY_OK(addr, len))) {
+			if ((i + 1) == sg_count)
+				end = true;
+			dwcmshc_cqhci_set_tran_desc(desc, addr, len, end, dma64);
+			desc += cq_host->trans_desc_len;
+		} else {
+			offset = addr & (SZ_128M - 1);
+			tmplen = SZ_128M - offset;
+			dwcmshc_cqhci_set_tran_desc(desc, addr, tmplen, end, dma64);
+			desc += cq_host->trans_desc_len;
+
+			if ((i + 1) == sg_count)
+				end = true;
+
+			addr += tmplen;
+			len -= tmplen;
+			dwcmshc_cqhci_set_tran_desc(desc, addr, len, end, dma64);
+			desc += cq_host->trans_desc_len;
+		}
+	}
+}
+
+static void dwcmshc_cqhci_dumpregs(struct mmc_host *mmc)
+{
+	sdhci_dumpregs(mmc_priv(mmc));
+}
+
 static void dwcmshc_rk3568_set_clock(struct sdhci_host *host, unsigned int clock)
 {
 	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
@@ -345,6 +495,7 @@ 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 = {
@@ -379,6 +530,70 @@ static const struct sdhci_pltfm_data sdhci_dwcmshc_rk35xx_pdata = {
 		   SDHCI_QUIRK2_CLOCK_DIV_ZERO_BROKEN,
 };
 
+static const struct cqhci_host_ops dwcmshc_cqhci_ops = {
+	.enable		= dwcmshc_sdhci_cqe_enable,
+	.disable	= dwcmshc_sdhci_cqe_disable,
+	.dumpregs	= dwcmshc_cqhci_dumpregs,
+	.prep_tran_desc	= dwcmshc_cqhci_prep_tran_desc,
+};
+
+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;
@@ -471,7 +686,7 @@ static int dwcmshc_probe(struct platform_device *pdev)
 	struct rk35xx_priv *rk_priv = NULL;
 	const struct sdhci_pltfm_data *pltfm_data;
 	int err;
-	u32 extra;
+	u32 extra, caps;
 
 	pltfm_data = device_get_match_data(&pdev->dev);
 	if (!pltfm_data) {
@@ -519,6 +734,8 @@ 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;
@@ -547,6 +764,10 @@ 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;
 
 	pm_runtime_get_noresume(dev);
@@ -557,6 +778,14 @@ static int dwcmshc_probe(struct platform_device *pdev)
 	if (err)
 		goto err_rpm;
 
+	/* 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);
 
-- 
2.30.2

Re: [PATCH v2 1/2] mmc: cqhci: Add cqhci_set_tran_desc() callback

[kernel test robot]

Hi Sergey,

kernel test robot noticed the following build warnings:

[auto build test WARNING on linus/master]
[also build test WARNING on ulf-hansson-mmc-mirror/next v6.6-rc3 next-20230926]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Sergey-Khimich/mmc-cqhci-Add-cqhci_set_tran_desc-callback/20230926-170331
base:   linus/master
patch link:    https://lore.kernel.org/r/20230926090242.105020-2-serghox%40gmail.com
patch subject: [PATCH v2 1/2] mmc: cqhci: Add cqhci_set_tran_desc() callback
config: alpha-allyesconfig (https://download.01.org/0day-ci/archive/20230927/202309270807.VoVn81m6-lkp@intel.com/config)
compiler: alpha-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20230927/202309270807.VoVn81m6-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202309270807.VoVn81m6-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from drivers/mmc/host/sdhci_am654.c:17:
>> drivers/mmc/host/cqhci.h:296:39: warning: 'struct mmc_data' declared inside parameter list will not be visible outside of this definition or declaration
     296 |         void (*prep_tran_desc)(struct mmc_data *data, struct cqhci_host *cq_host,
         |                                       ^~~~~~~~


vim +296 drivers/mmc/host/cqhci.h

   281	
   282	struct cqhci_host_ops {
   283		void (*dumpregs)(struct mmc_host *mmc);
   284		void (*write_l)(struct cqhci_host *host, u32 val, int reg);
   285		u32 (*read_l)(struct cqhci_host *host, int reg);
   286		void (*enable)(struct mmc_host *mmc);
   287		void (*disable)(struct mmc_host *mmc, bool recovery);
   288		void (*update_dcmd_desc)(struct mmc_host *mmc, struct mmc_request *mrq,
   289					 u64 *data);
   290		void (*pre_enable)(struct mmc_host *mmc);
   291		void (*post_disable)(struct mmc_host *mmc);
   292	#ifdef CONFIG_MMC_CRYPTO
   293		int (*program_key)(struct cqhci_host *cq_host,
   294				   const union cqhci_crypto_cfg_entry *cfg, int slot);
   295	#endif
 > 296		void (*prep_tran_desc)(struct mmc_data *data, struct cqhci_host *cq_host,
   297				       u8 *desc, int sg_count);
   298	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH v2 1/2] mmc: cqhci: Add cqhci_set_tran_desc() callback

[kernel test robot]

Hi Sergey,

kernel test robot noticed the following build warnings:

[auto build test WARNING on linus/master]
[also build test WARNING on ulf-hansson-mmc-mirror/next v6.6-rc3 next-20230929]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Sergey-Khimich/mmc-cqhci-Add-cqhci_set_tran_desc-callback/20230926-170331
base:   linus/master
patch link:    https://lore.kernel.org/r/20230926090242.105020-2-serghox%40gmail.com
patch subject: [PATCH v2 1/2] mmc: cqhci: Add cqhci_set_tran_desc() callback
config: hexagon-allyesconfig (https://download.01.org/0day-ci/archive/20230930/202309300806.dcR19kcE-lkp@intel.com/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project.git 4a5ac14ee968ff0ad5d2cc1ffa0299048db4c88a)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20230930/202309300806.dcR19kcE-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202309300806.dcR19kcE-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from drivers/mmc/host/sdhci_am654.c:9:
   In file included from include/linux/iopoll.h:14:
   In file included from include/linux/io.h:13:
   In file included from arch/hexagon/include/asm/io.h:337:
   include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     547 |         val = __raw_readb(PCI_IOBASE + addr);
         |                           ~~~~~~~~~~ ^
   include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     560 |         val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu'
      37 | #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
         |                                                   ^
   In file included from drivers/mmc/host/sdhci_am654.c:9:
   In file included from include/linux/iopoll.h:14:
   In file included from include/linux/io.h:13:
   In file included from arch/hexagon/include/asm/io.h:337:
   include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     573 |         val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu'
      35 | #define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
         |                                                   ^
   In file included from drivers/mmc/host/sdhci_am654.c:9:
   In file included from include/linux/iopoll.h:14:
   In file included from include/linux/io.h:13:
   In file included from arch/hexagon/include/asm/io.h:337:
   include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     584 |         __raw_writeb(value, PCI_IOBASE + addr);
         |                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     594 |         __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     604 |         __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   In file included from drivers/mmc/host/sdhci_am654.c:17:
>> drivers/mmc/host/cqhci.h:296:32: warning: declaration of 'struct mmc_data' will not be visible outside of this function [-Wvisibility]
     296 |         void (*prep_tran_desc)(struct mmc_data *data, struct cqhci_host *cq_host,
         |                                       ^
   7 warnings generated.


vim +296 drivers/mmc/host/cqhci.h

   281	
   282	struct cqhci_host_ops {
   283		void (*dumpregs)(struct mmc_host *mmc);
   284		void (*write_l)(struct cqhci_host *host, u32 val, int reg);
   285		u32 (*read_l)(struct cqhci_host *host, int reg);
   286		void (*enable)(struct mmc_host *mmc);
   287		void (*disable)(struct mmc_host *mmc, bool recovery);
   288		void (*update_dcmd_desc)(struct mmc_host *mmc, struct mmc_request *mrq,
   289					 u64 *data);
   290		void (*pre_enable)(struct mmc_host *mmc);
   291		void (*post_disable)(struct mmc_host *mmc);
   292	#ifdef CONFIG_MMC_CRYPTO
   293		int (*program_key)(struct cqhci_host *cq_host,
   294				   const union cqhci_crypto_cfg_entry *cfg, int slot);
   295	#endif
 > 296		void (*prep_tran_desc)(struct mmc_data *data, struct cqhci_host *cq_host,
   297				       u8 *desc, int sg_count);
   298	

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