From: Kyle Roeschley <kyle.roeschley@xxxxxx>
On some SD host controllers, 1.8V signaling is required for reliable
operation of the part. Add a capability which says that we must switch
to 1.8V signaling during card initialization.
Signed-off-by: Kyle Roeschley <kyle.roeschley@xxxxxx>
Signed-off-by: Jennifer Dahm <jennifer.dahm@xxxxxx>
---
drivers/mmc/core/sd.c | 7 +++++++
include/linux/mmc/host.h | 1 +
2 files changed, 8 insertions(+)
diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index baf3d5d..b259671 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -782,6 +782,13 @@ int mmc_sd_get_cid(struct mmc_host *host, u32 ocr, u32 *cid, u32 *rocr)
}
}
+ if (host->caps2 & MMC_CAP2_REQUIRE_1_8V &&
+ host->ios.signal_voltage != MMC_SIGNAL_VOLTAGE_180) {
+ pr_err("%s: Host requires UHS-capable card\n",
+ mmc_hostname(host));
+ return -EINVAL;
+ }
+
err = mmc_send_cid(host, cid);
return err;
}
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 8514623..4d58c10 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -354,6 +354,7 @@ struct mmc_host {
#define MMC_CAP2_NO_MMC (1 << 22) /* Do not send (e)MMC commands during initialization */
#define MMC_CAP2_CQE (1 << 23) /* Has eMMC command queue engine */
#define MMC_CAP2_CQE_DCMD (1 << 24) /* CQE can issue a direct command */
+#define MMC_CAP2_REQUIRE_1_8V (1 << 25) /* Host requires 1.8V signalling */
int fixed_drv_type; /* fixed driver type for non-removable media */
--
2.7.4
--
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