From: Philipp Zabel <p.zabel@pengutronix.de>
To: barebox@lists.infradead.org
Subject: [PATCH] mmc: allow skipping SD card initialization
Date: Wed, 20 Sep 2017 17:50:44 +0200 [thread overview]
Message-ID: <20170920155044.1841-1-p.zabel@pengutronix.de> (raw)
This patch allows to skip SD card initialization for eMMCs by setting
the "no-sd" property in the host controller device tree node. Avoiding
two SD command timeouts speeds up detection time by well over 200 ms.
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
---
drivers/mci/mci-core.c | 12 ++++++++----
include/mci.h | 1 +
2 files changed, 9 insertions(+), 4 deletions(-)
diff --git a/drivers/mci/mci-core.c b/drivers/mci/mci-core.c
index 07911d43d..208b7666d 100644
--- a/drivers/mci/mci-core.c
+++ b/drivers/mci/mci-core.c
@@ -1682,10 +1682,13 @@ static int mci_card_probe(struct mci *mci)
}
/* Check if this card can handle the "SD Card Physical Layer Specification 2.0" */
- rc = sd_send_if_cond(mci);
- rc = sd_send_op_cond(mci);
- if (rc && rc == -ETIMEDOUT) {
- /* If the command timed out, we check for an MMC card */
+ if (!host->no_sd) {
+ rc = sd_send_if_cond(mci);
+ rc = sd_send_op_cond(mci);
+ }
+ if (host->no_sd || rc == -ETIMEDOUT) {
+ /* If SD card initialization was skipped or if it timed out,
+ * we check for an MMC card */
dev_dbg(&mci->dev, "Card seems to be a MultiMediaCard\n");
rc = mmc_send_op_cond(mci);
}
@@ -1904,6 +1907,7 @@ void mci_of_parse_node(struct mci_host *host,
}
host->non_removable = of_property_read_bool(np, "non-removable");
+ host->no_sd = of_property_read_bool(np, "no-sd");
}
void mci_of_parse(struct mci_host *host)
diff --git a/include/mci.h b/include/mci.h
index d3115e8cc..1f6533391 100644
--- a/include/mci.h
+++ b/include/mci.h
@@ -403,6 +403,7 @@ struct mci_host {
unsigned dsr_val; /**< optional dsr value */
int use_dsr; /**< optional dsr usage flag */
bool non_removable; /**< device is non removable */
+ bool no_sd; /**< do not send SD commands during initialization */
struct regulator *supply;
/** init the host interface */
--
2.11.0
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next reply other threads:[~2017-09-20 15:51 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-20 15:50 Philipp Zabel [this message]
2017-09-26 6:53 ` Sascha Hauer
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