[PATCH v1 2/3] mmc: core: Add support for SDIO async interrupt

[Axe Yang]

If cap-sdio-async-int flag is set in host dts node, parse EAI
information from SDIO CCCR interrupt externsion segment. If async
interrupt is supported by SDIO card then send command to card to
enable it and set enable_async_int flag in sdio_cccr structure to 1.
The parse flow is implemented in sdio_read_cccr().

Signed-off-by: Axe Yang <axe.yang at mediatek.com>
---
 drivers/mmc/core/host.c  |  2 ++
 drivers/mmc/core/sdio.c  | 17 +++++++++++++++++
 include/linux/mmc/card.h |  3 ++-
 include/linux/mmc/host.h |  1 +
 include/linux/mmc/sdio.h |  5 +++++
 5 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index d4683b1d263f..7ad60fab099a 100644
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -401,6 +401,8 @@ int mmc_of_parse(struct mmc_host *host)
 	if (device_property_read_bool(dev, "no-mmc-hs400"))
 		host->caps2 &= ~(MMC_CAP2_HS400_1_8V | MMC_CAP2_HS400_1_2V |
 				 MMC_CAP2_HS400_ES);
+	if (device_property_read_bool(dev, "cap-sdio-async-int"))
+		host->caps2 |= MMC_CAP2_SDIO_ASYNC_INT;
 
 	/* Must be after "non-removable" check */
 	if (device_property_read_u32(dev, "fixed-emmc-driver-type", &drv_type) == 0) {
diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
index 68edf7a615be..335e4ada733a 100644
--- a/drivers/mmc/core/sdio.c
+++ b/drivers/mmc/core/sdio.c
@@ -225,6 +225,23 @@ static int sdio_read_cccr(struct mmc_card *card, u32 ocr)
 				card->sw_caps.sd3_drv_type |= SD_DRIVER_TYPE_C;
 			if (data & SDIO_DRIVE_SDTD)
 				card->sw_caps.sd3_drv_type |= SD_DRIVER_TYPE_D;
+
+			if (card->host->caps2 & MMC_CAP2_SDIO_ASYNC_INT) {
+				ret = mmc_io_rw_direct(card, 0, 0, SDIO_CCCR_INTERRUPT_EXT, 0,
+						       &data);
+				if (ret)
+					goto out;
+
+				if (data & SDIO_INTERRUPT_EXT_SAI) {
+					data |= SDIO_INTERRUPT_EXT_EAI;
+					ret = mmc_io_rw_direct(card, 1, 0, SDIO_CCCR_INTERRUPT_EXT,
+							       data, NULL);
+					if (ret)
+						goto out;
+
+					card->cccr.enable_async_int = 1;
+				}
+			}
 		}
 
 		/* if no uhs mode ensure we check for high speed */
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index 37f975875102..b0deb8ca8eeb 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -219,7 +219,8 @@ struct sdio_cccr {
 				wide_bus:1,
 				high_power:1,
 				high_speed:1,
-				disable_cd:1;
+				disable_cd:1,
+				enable_async_int:1;
 };
 
 struct sdio_cis {
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 0c0c9a0fdf57..60c8ebe1a5e8 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -399,6 +399,7 @@ struct mmc_host {
 #define MMC_CAP2_CRYPTO		0
 #endif
 #define MMC_CAP2_ALT_GPT_TEGRA	(1 << 28)	/* Host with eMMC that has GPT entry at a non-standard location */
+#define MMC_CAP2_SDIO_ASYNC_INT	(1 << 29)	/* SDIO host supports asynchronous interrupt */
 
 	int			fixed_drv_type;	/* fixed driver type for non-removable media */
 
diff --git a/include/linux/mmc/sdio.h b/include/linux/mmc/sdio.h
index 2a05d1ac4f0e..1ef400f28642 100644
--- a/include/linux/mmc/sdio.h
+++ b/include/linux/mmc/sdio.h
@@ -159,6 +159,11 @@
 #define  SDIO_DTSx_SET_TYPE_A	(1 << SDIO_DRIVE_DTSx_SHIFT)
 #define  SDIO_DTSx_SET_TYPE_C	(2 << SDIO_DRIVE_DTSx_SHIFT)
 #define  SDIO_DTSx_SET_TYPE_D	(3 << SDIO_DRIVE_DTSx_SHIFT)
+
+#define SDIO_CCCR_INTERRUPT_EXT	0x16
+#define SDIO_INTERRUPT_EXT_SAI	(1 << 0)
+#define SDIO_INTERRUPT_EXT_EAI	(1 << 1)
+
 /*
  * Function Basic Registers (FBR)
  */
-- 
2.25.1