From: Biju Das <biju.das.jz@bp.renesas.com>

As per the RZ/{G2L,G3E} HW manual SD_BUF0 can be accessed by 16/32/64
bits. Most of the data transfer in SD/SDIO/eMMC mode is more than 8 bytes.
During testing it is found that, if the DMA buffer is not aligned to 128
bit it fallback to PIO mode. In such cases, 64-bit access is much more
efficient than the current 16-bit.

Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
---
RFT->v2:
 * Collected tags
 * Fixed the buid error reported by the bot by guarding the code with
   CONFIG_64BIT.
---
 drivers/mmc/host/tmio_mmc.h        | 14 +++++++++++++
 drivers/mmc/host/tmio_mmc_core.c   | 33 ++++++++++++++++++++++++++++++
 include/linux/platform_data/tmio.h |  3 +++
 3 files changed, 50 insertions(+)

diff --git a/drivers/mmc/host/tmio_mmc.h b/drivers/mmc/host/tmio_mmc.h
index d730b7633ae1..8cf9be9833b2 100644
--- a/drivers/mmc/host/tmio_mmc.h
+++ b/drivers/mmc/host/tmio_mmc.h
@@ -242,6 +242,20 @@ static inline void sd_ctrl_read32_rep(struct tmio_mmc_host *host, int addr,
 	ioread32_rep(host->ctl + (addr << host->bus_shift), buf, count);
 }
 
+#ifdef CONFIG_64BIT
+static inline void sd_ctrl_read64_rep(struct tmio_mmc_host *host, int addr,
+				      u64 *buf, int count)
+{
+	ioread64_rep(host->ctl + (addr << host->bus_shift), buf, count);
+}
+
+static inline void sd_ctrl_write64_rep(struct tmio_mmc_host *host, int addr,
+				       const u64 *buf, int count)
+{
+	iowrite64_rep(host->ctl + (addr << host->bus_shift), buf, count);
+}
+#endif
+
 static inline void sd_ctrl_write16(struct tmio_mmc_host *host, int addr,
 				   u16 val)
 {
diff --git a/drivers/mmc/host/tmio_mmc_core.c b/drivers/mmc/host/tmio_mmc_core.c
index 21c2f9095bac..775e0d9353d5 100644
--- a/drivers/mmc/host/tmio_mmc_core.c
+++ b/drivers/mmc/host/tmio_mmc_core.c
@@ -349,6 +349,39 @@ static void tmio_mmc_transfer_data(struct tmio_mmc_host *host,
 	/*
 	 * Transfer the data
 	 */
+#ifdef CONFIG_64BIT
+	if (host->pdata->flags & TMIO_MMC_64BIT_DATA_PORT) {
+		u64 *buf64 = (u64 *)buf;
+		u64 data = 0;
+
+		if (count >= 8) {
+			if (is_read)
+				sd_ctrl_read64_rep(host, CTL_SD_DATA_PORT,
+						   buf64, count >> 3);
+			else
+				sd_ctrl_write64_rep(host, CTL_SD_DATA_PORT,
+						    buf64, count >> 3);
+		}
+
+		/* if count was multiple of 8 */
+		if (!(count & 0x7))
+			return;
+
+		buf64 += count >> 3;
+		count %= 8;
+
+		if (is_read) {
+			sd_ctrl_read64_rep(host, CTL_SD_DATA_PORT, &data, 1);
+			memcpy(buf64, &data, count);
+		} else {
+			memcpy(&data, buf64, count);
+			sd_ctrl_write64_rep(host, CTL_SD_DATA_PORT, &data, 1);
+		}
+
+		return;
+	}
+#endif
+
 	if (host->pdata->flags & TMIO_MMC_32BIT_DATA_PORT) {
 		u32 data = 0;
 		u32 *buf32 = (u32 *)buf;
diff --git a/include/linux/platform_data/tmio.h b/include/linux/platform_data/tmio.h
index b060124ba1ae..426291713b83 100644
--- a/include/linux/platform_data/tmio.h
+++ b/include/linux/platform_data/tmio.h
@@ -47,6 +47,9 @@
 /* Some controllers have a CBSY bit */
 #define TMIO_MMC_HAVE_CBSY		BIT(11)
 
+/* Some controllers have a 64-bit wide data port register */
+#define TMIO_MMC_64BIT_DATA_PORT	BIT(12)
+
 struct tmio_mmc_data {
 	void				*chan_priv_tx;
 	void				*chan_priv_rx;
-- 
2.43.0

Hi Biju,

kernel test robot noticed the following build errors:

[auto build test ERROR on linus/master]
[also build test ERROR on ulf-hansson-mmc-mirror/next v6.16 next-20250729]
[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/Biju/mmc-tmio-Add-64-bit-read-write-support-for-SD_BUF0-in-polling-mode/20250728-001022
base:   linus/master
patch link:    https://lore.kernel.org/r/20250727160731.106312-2-biju.das.jz%40bp.renesas.com
patch subject: [PATCH v2 1/2] mmc: tmio: Add 64-bit read/write support for SD_BUF0 in polling mode
config: powerpc64-randconfig-001-20250730 (https://download.01.org/0day-ci/archive/20250730/202507301421.AmWhOZBk-lkp@intel.com/config)
compiler: clang version 22.0.0git (https://github.com/llvm/llvm-project 78c460bbe8f1fc17e2e66b37edf419ccecbfecba)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250730/202507301421.AmWhOZBk-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/202507301421.AmWhOZBk-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from drivers/mmc/host/uniphier-sd.c:21:
>> drivers/mmc/host/tmio_mmc.h:249:2: error: call to undeclared function 'ioread64_rep'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     249 |         ioread64_rep(host->ctl + (addr << host->bus_shift), buf, count);
         |         ^
>> drivers/mmc/host/tmio_mmc.h:255:2: error: call to undeclared function 'iowrite64_rep'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     255 |         iowrite64_rep(host->ctl + (addr << host->bus_shift), buf, count);
         |         ^
   2 errors generated.


vim +/ioread64_rep +249 drivers/mmc/host/tmio_mmc.h

   244	
   245	#ifdef CONFIG_64BIT
   246	static inline void sd_ctrl_read64_rep(struct tmio_mmc_host *host, int addr,
   247					      u64 *buf, int count)
   248	{
 > 249		ioread64_rep(host->ctl + (addr << host->bus_shift), buf, count);
   250	}
   251	
   252	static inline void sd_ctrl_write64_rep(struct tmio_mmc_host *host, int addr,
   253					       const u64 *buf, int count)
   254	{
 > 255		iowrite64_rep(host->ctl + (addr << host->bus_shift), buf, count);
   256	}
   257	#endif
   258	

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

>    In file included from drivers/mmc/host/uniphier-sd.c:21:
> >> drivers/mmc/host/tmio_mmc.h:249:2: error: call to undeclared function 'ioread64_rep'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
>      249 |         ioread64_rep(host->ctl + (addr << host->bus_shift), buf, count);
>          |         ^
> >> drivers/mmc/host/tmio_mmc.h:255:2: error: call to undeclared function 'iowrite64_rep'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
>      255 |         iowrite64_rep(host->ctl + (addr << host->bus_shift), buf, count);
>          |         ^

Sigh, then the guard seems to be ARM64 after all :(

Hi Wolfram,

On Wed, 30 Jul 2025 at 11:17, Wolfram Sang <wsa-dev@sang-engineering.com> wrote:
> >    In file included from drivers/mmc/host/uniphier-sd.c:21:
> > >> drivers/mmc/host/tmio_mmc.h:249:2: error: call to undeclared function 'ioread64_rep'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
> >      249 |         ioread64_rep(host->ctl + (addr << host->bus_shift), buf, count);
> >          |         ^
> > >> drivers/mmc/host/tmio_mmc.h:255:2: error: call to undeclared function 'iowrite64_rep'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
> >      255 |         iowrite64_rep(host->ctl + (addr << host->bus_shift), buf, count);
> >          |         ^
>
> Sigh, then the guard seems to be ARM64 after all :(

ioread64_rep() is defined in include/asm-generic/io.h, and powerpc does
include that.

Perhaps drivers/mmc/host/tmio_mmc.h should just include <linux/io.h>?

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds