mmc: core: Add support for SDIO wakeup interrupt

If wakeup-source flag is set in host dts node, parse EAI information
from SDIO CCCR interrupt externsion segment for in-band wakeup. If
async interrupt is supported by SDIO card then enable it and set
enable_async_irq flag in sdio_cccr structure to 1. The parse flow is
implemented in sdio_read_cccr().

Reviewed-by: AngeloGioacchino Del Regno <[e-mail]>
Signed-off-by: Axe Yang <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Ulf Hansson <[e-mail]>

drivers/mmc/core/sdio.c

···
 				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;
+
+			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_irq = 1;
+			}
 		}
 
 		/* if no uhs mode ensure we check for high speed */

include/linux/mmc/card.h

···
 				wide_bus:1,
 				high_power:1,
 				high_speed:1,
-				disable_cd:1;
+				disable_cd:1,
+				enable_async_irq:1;
 };
 
 struct sdio_cis {
···
 static inline bool mmc_large_sector(struct mmc_card *card)
 {
 	return card->ext_csd.data_sector_size == 4096;
+}
+
+static inline int mmc_card_enable_async_irq(struct mmc_card *card)
+{
+	return card->cccr.enable_async_irq;
 }
 
 bool mmc_card_is_blockaddr(struct mmc_card *card);

include/linux/mmc/sdio.h

···
 #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)
  */