diff options
| author | ian <ian@FreeBSD.org> | 2015-12-18 01:25:30 +0000 |
|---|---|---|
| committer | ian <ian@FreeBSD.org> | 2015-12-18 01:25:30 +0000 |
| commit | 7292e552617fd10f13dffc4202d64eeddbc14bcb (patch) | |
| tree | 794fb3c66e06ba5d74a78006e507f274158065a0 /sys/arm/freescale/imx/imx_sdhci.c | |
| parent | a12e9d2b9f45e8ba9e4392031bda53e5d047180d (diff) | |
| download | FreeBSD-src-7292e552617fd10f13dffc4202d64eeddbc14bcb.zip FreeBSD-src-7292e552617fd10f13dffc4202d64eeddbc14bcb.tar.gz | |
Fix the clock divisor calc for imx6 sdcard bus speed.
I don't know what alternate universe I was inhabiting when I wrote it
originally, but apparently the basic workings of mathematics were different
than in this universe. I also can't explain how it ever worked, except "by
accident", because completely bogus values were being written into the
divisor register.
Diffstat (limited to 'sys/arm/freescale/imx/imx_sdhci.c')
| -rw-r--r-- | sys/arm/freescale/imx/imx_sdhci.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/sys/arm/freescale/imx/imx_sdhci.c b/sys/arm/freescale/imx/imx_sdhci.c index 6acc86e..17edf07 100644 --- a/sys/arm/freescale/imx/imx_sdhci.c +++ b/sys/arm/freescale/imx/imx_sdhci.c @@ -522,12 +522,19 @@ imx_sdhc_set_clock(struct imx_sdhci_softc *sc, int enable) else freq = sc->baseclk_hz / (2 * divisor); - for (prescale = 2; prescale < freq / prescale / 16;) + for (prescale = 2; freq < sc->baseclk_hz / (prescale * 16);) prescale <<= 1; - for (divisor = 1; freq < freq / prescale / divisor;) + for (divisor = 1; freq < sc->baseclk_hz / (prescale * divisor);) ++divisor; +#ifdef DEBUG + device_printf(sc->dev, + "desired SD freq: %d, actual: %d; base %d prescale %d divisor %d\n", + freq, sc->baseclk_hz / (prescale * divisor), sc->baseclk_hz, + prescale, divisor); +#endif + prescale >>= 1; divisor -= 1; |
