mmc: core: support HPI send command

HPI command is defined in eMMC4.41.
This feature is important for eMMC4.5 devices.

Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index de5900a..fb5bf01 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -448,6 +448,21 @@
 	}
 
 	if (card->ext_csd.rev >= 5) {
+		/* check whether the eMMC card supports HPI */
+		if (ext_csd[EXT_CSD_HPI_FEATURES] & 0x1) {
+			card->ext_csd.hpi = 1;
+			if (ext_csd[EXT_CSD_HPI_FEATURES] & 0x2)
+				card->ext_csd.hpi_cmd =	MMC_STOP_TRANSMISSION;
+			else
+				card->ext_csd.hpi_cmd = MMC_SEND_STATUS;
+			/*
+			 * Indicate the maximum timeout to close
+			 * a command interrupted by HPI
+			 */
+			card->ext_csd.out_of_int_time =
+				ext_csd[EXT_CSD_OUT_OF_INTERRUPT_TIME] * 10;
+		}
+
 		card->ext_csd.rel_param = ext_csd[EXT_CSD_WR_REL_PARAM];
 		card->ext_csd.rst_n_function = ext_csd[EXT_CSD_RST_N_FUNCTION];
 	}
@@ -896,6 +911,22 @@
 	}
 
 	/*
+	 * Enable HPI feature (if supported)
+	 */
+	if (card->ext_csd.hpi) {
+		err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+			EXT_CSD_HPI_MGMT, 1, 0);
+		if (err && err != -EBADMSG)
+			goto free_card;
+		if (err) {
+			pr_warning("%s: Enabling HPI failed\n",
+				   mmc_hostname(card->host));
+			err = 0;
+		} else
+			card->ext_csd.hpi_en = 1;
+	}
+
+	/*
 	 * Compute bus speed.
 	 */
 	max_dtr = (unsigned int)-1;