diff options
Diffstat (limited to 'target/linux/brcm2708/patches-4.14/950-0166-mmc-bcm2835-sdhost-Support-underclocking.patch')
| -rw-r--r-- | target/linux/brcm2708/patches-4.14/950-0166-mmc-bcm2835-sdhost-Support-underclocking.patch | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.14/950-0166-mmc-bcm2835-sdhost-Support-underclocking.patch b/target/linux/brcm2708/patches-4.14/950-0166-mmc-bcm2835-sdhost-Support-underclocking.patch new file mode 100644 index 0000000000..feca38df3a --- /dev/null +++ b/target/linux/brcm2708/patches-4.14/950-0166-mmc-bcm2835-sdhost-Support-underclocking.patch @@ -0,0 +1,43 @@ +From c03a6b0585e7c469c199d349405b3967bcf18672 Mon Sep 17 00:00:00 2001 +From: Phil Elwell <phil@raspberrypi.org> +Date: Mon, 22 Jan 2018 12:17:27 +0000 +Subject: [PATCH 166/454] mmc: bcm2835-sdhost: Support underclocking + +Support underclocking of the SD bus in two ways: +1. using the max-frequency DT property (which currently has no DT + parameter), and +2. using the exiting sd_overclock parameter. + +The two methods differ slightly - in the former the MMC subsystem is +aware of the underclocking, while in the latter it isn't - but the +end results should be the same. + +See: https://github.com/raspberrypi/linux/issues/2350 + +Signed-off-by: Phil Elwell <phil@raspberrypi.org> +--- + drivers/mmc/host/bcm2835-sdhost.c | 6 +++--- + 1 file changed, 3 insertions(+), 3 deletions(-) + +--- a/drivers/mmc/host/bcm2835-sdhost.c ++++ b/drivers/mmc/host/bcm2835-sdhost.c +@@ -1519,8 +1519,7 @@ void bcm2835_sdhost_set_clock(struct bcm + if (host->debug) + pr_info("%s: set_clock(%d)\n", mmc_hostname(host->mmc), clock); + +- if ((host->overclock_50 > 50) && +- (clock == 50*MHZ)) ++ if (host->overclock_50 && (clock == 50*MHZ)) + clock = host->overclock_50 * MHZ + (MHZ - 1); + + /* The SDCDIV register has 11 bits, and holds (div - 2). +@@ -1894,7 +1893,8 @@ int bcm2835_sdhost_add_host(struct bcm28 + + mmc = host->mmc; + +- mmc->f_max = host->max_clk; ++ if (!mmc->f_max || mmc->f_max > host->max_clk) ++ mmc->f_max = host->max_clk; + mmc->f_min = host->max_clk / SDCDIV_MAX_CDIV; + + mmc->max_busy_timeout = (~(unsigned int)0)/(mmc->f_max/1000); |