mmc: core: Add helper function for EXT_CSD support

The helper function mmc_can_ext_csd() will return a positive value if
the card supports the EXT_CSD register. Start using it at relavant
places in the mmc core.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/core/mmc.c

@@ -190,7 +190,7 @@ static int mmc_get_ext_csd(struct mmc_card *card, u8 **new_ext_csd)
 
 	*new_ext_csd = NULL;
 
-	if (card->csd.mmca_vsn < CSD_SPEC_VER_4)
+	if (!mmc_can_ext_csd(card))
 		return 0;
 
 	/*
@@ -852,7 +852,7 @@ static int mmc_select_powerclass(struct mmc_card *card)
 	int err, ddr;
 
 	/* Power class selection is supported for versions >= 4.0 */
-	if (card->csd.mmca_vsn < CSD_SPEC_VER_4)
+	if (!mmc_can_ext_csd(card))
 		return 0;
 
 	bus_width = host->ios.bus_width;
@@ -913,7 +913,7 @@ static int mmc_select_bus_width(struct mmc_card *card)
 	unsigned idx, bus_width = 0;
 	int err = 0;
 
-	if ((card->csd.mmca_vsn < CSD_SPEC_VER_4) &&
+	if (!mmc_can_ext_csd(card) &&
 	    !(host->caps & (MMC_CAP_4_BIT_DATA | MMC_CAP_8_BIT_DATA)))
 		return 0;
 
@@ -1154,7 +1154,7 @@ static int mmc_select_timing(struct mmc_card *card)
 {
 	int err = 0;
 
-	if (card->csd.mmca_vsn < CSD_SPEC_VER_4)
+	if (!mmc_can_ext_csd(card))
 		goto bus_speed;
 
 	if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200)

drivers/mmc/core/mmc_ops.c

@@ -675,3 +675,8 @@ int mmc_send_hpi_cmd(struct mmc_card *card, u32 *status)
 
 	return 0;
 }
+
+int mmc_can_ext_csd(struct mmc_card *card)
+{
+	return (card && card->csd.mmca_vsn > CSD_SPEC_VER_3);
+}

drivers/mmc/core/mmc_ops.h

@@ -26,6 +26,7 @@ int mmc_spi_read_ocr(struct mmc_host *host, int highcap, u32 *ocrp);
 int mmc_spi_set_crc(struct mmc_host *host, int use_crc);
 int mmc_bus_test(struct mmc_card *card, u8 bus_width);
 int mmc_send_hpi_cmd(struct mmc_card *card, u32 *status);
+int mmc_can_ext_csd(struct mmc_card *card);
 
 #endif