From: "Michał Mirosław" <mirq-linux@rere.qmqm.pl>
To: Adrian Hunter <adrian.hunter@intel.com>,
Ulf Hansson <ulf.hansson@linaro.org>
Cc: linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2] mmc: sdhci: fix minimum clock rate for v3 controller
Date: Wed, 15 Jan 2020 09:32:16 +0100 [thread overview]
Message-ID: <36180c2b31b154b482892d6c7a3c6d5f386a6a73.1579077085.git.mirq-linux@rere.qmqm.pl> (raw)
For SDHCIv3+ with programmable clock mode, minimal clock frequency is
still base clock / max(divider). Minimal programmable clock frequency is
always greater than minimal divided clock frequency. Without this patch,
SDHCI uses out-of-spec initial frequency when multiplier is big enough:
mmc1: mmc_rescan_try_freq: trying to init card at 468750 Hz
[for 480 MHz source clock divided by 1024]
The code in sdhci_calc_clk() already chooses a correct SDCLK clock source.
Cc: stable@vger.kernel.org
Fixes: c3ed3877625f ("mmc: sdhci: add support for programmable clock mode")
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
---
v2: extend commitmsg and add comment
---
drivers/mmc/host/sdhci.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 96609c961465..fde510c55c89 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -3903,11 +3903,11 @@ int sdhci_setup_host(struct sdhci_host *host)
if (host->ops->get_min_clock)
mmc->f_min = host->ops->get_min_clock(host);
else if (host->version >= SDHCI_SPEC_300) {
- if (host->clk_mul) {
- mmc->f_min = (host->max_clk * host->clk_mul) / 1024;
+ if (host->clk_mul)
max_clk = host->max_clk * host->clk_mul;
- } else
- mmc->f_min = host->max_clk / SDHCI_MAX_DIV_SPEC_300;
+ /* minimal divided clock rate is always less than minimal
+ * programmable clock rate */
+ mmc->f_min = host->max_clk / SDHCI_MAX_DIV_SPEC_300;
} else
mmc->f_min = host->max_clk / SDHCI_MAX_DIV_SPEC_200;
--
2.20.1
next reply other threads:[~2020-01-15 8:32 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-15 8:32 Michał Mirosław [this message]
2020-01-15 8:55 ` [PATCH v2] mmc: sdhci: fix minimum clock rate for v3 controller Adrian Hunter
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=36180c2b31b154b482892d6c7a3c6d5f386a6a73.1579077085.git.mirq-linux@rere.qmqm.pl \
--to=mirq-linux@rere.qmqm.pl \
--cc=adrian.hunter@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mmc@vger.kernel.org \
--cc=ulf.hansson@linaro.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).