[src/trunk]: src/sys/dev/sdmmc Add support for SDHCI 3.0 bus clock generation...

[jakllsch <jakllsch%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/c0810438588c
branches:  trunk
changeset: 783447:c0810438588c
user:      jakllsch <jakllsch%NetBSD.org@localhost>
date:      Sat Dec 22 03:56:58 2012 +0000

description:
Add support for SDHCI 3.0 bus clock generation, which unlike 1.0 and 2.0
has support for non-power-of-two divisors from 1 to 1023. Additionally
restore finding the correct power-of-two divisor for standard-compliant
pre-3.0 SDHCI parts.  Also, calculate minimum divided clock for the
clkmsk-quirk parts correctly.

XXX Will future standard-compliant SDHCI versions have a SDHCI 3.0
backwards-compatible clock generator, or just SDHCI 1.0/2.0?

diffstat:

 sys/dev/sdmmc/sdhc.c |  50 +++++++++++++++++++++++++++++++++++++++-----------
 1 files changed, 39 insertions(+), 11 deletions(-)

diffs (82 lines):

diff -r 3499321f82c0 -r c0810438588c sys/dev/sdmmc/sdhc.c
--- a/sys/dev/sdmmc/sdhc.c      Fri Dec 21 19:39:48 2012 +0000
+++ b/sys/dev/sdmmc/sdhc.c      Sat Dec 22 03:56:58 2012 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: sdhc.c,v 1.37 2012/12/20 22:56:38 jakllsch Exp $       */
+/*     $NetBSD: sdhc.c,v 1.38 2012/12/22 03:56:58 jakllsch Exp $       */
 /*     $OpenBSD: sdhc.c,v 1.25 2009/01/13 19:44:20 grange Exp $        */
 
 /*
@@ -23,7 +23,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: sdhc.c,v 1.37 2012/12/20 22:56:38 jakllsch Exp $");
+__KERNEL_RCSID(0, "$NetBSD: sdhc.c,v 1.38 2012/12/22 03:56:58 jakllsch Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_sdmmc.h"
@@ -398,12 +398,18 @@
        saa.saa_sct = &sdhc_functions;
        saa.saa_sch = hp;
        saa.saa_dmat = hp->dmat;
-       saa.saa_clkmin = hp->clkbase / 256;
        saa.saa_clkmax = hp->clkbase;
        if (ISSET(sc->sc_flags, SDHC_FLAG_HAVE_CGM))
-               saa.saa_clkmin /= 2046;
+               saa.saa_clkmin = hp->clkbase / 256 / 2046;
        else if (ISSET(sc->sc_flags, SDHC_FLAG_HAVE_DVS))
-               saa.saa_clkmin /= 16;
+               saa.saa_clkmin = hp->clkbase / 256 / 16;
+       else if (hp->sc->sc_clkmsk != 0)
+               saa.saa_clkmin = hp->clkbase / (hp->sc->sc_clkmsk >>
+                   (ffs(hp->sc->sc_clkmsk) - 1));
+       else if (hp->specver == SDHC_SPEC_VERS_300)
+               saa.saa_clkmin = hp->clkbase / 0x3ff;
+       else
+               saa.saa_clkmin = hp->clkbase / 256;
        saa.saa_caps = SMC_CAPS_4BIT_MODE|SMC_CAPS_AUTO_STOP;
        if (ISSET(sc->sc_flags, SDHC_FLAG_8BIT_MODE))
                saa.saa_caps |= SMC_CAPS_8BIT_MODE;
@@ -795,13 +801,35 @@
                }
                /* No divisor found. */
                return false;
+       }
+       if (hp->sc->sc_clkmsk != 0) {
+               div = howmany(hp->clkbase, freq);
+               if (div > (hp->sc->sc_clkmsk >> (ffs(hp->sc->sc_clkmsk) - 1)))
+                       return false;
+               *divp = div << (ffs(hp->sc->sc_clkmsk) - 1);
+               //freq = hp->clkbase / div;
+               return true;
+       }
+       if (hp->specver == SDHC_SPEC_VERS_300) {
+               div = howmany(hp->clkbase, freq);
+               if (div > 0x3ff)
+                       return false;
+               *divp = (((div >> 8) & SDHC_SDCLK_XDIV_MASK)
+                        << SDHC_SDCLK_XDIV_SHIFT) |
+                       (((div >> 0) & SDHC_SDCLK_DIV_MASK)
+                        << SDHC_SDCLK_DIV_SHIFT);
+               //freq = hp->clkbase / div;
+               return true;
        } else {
-               if (hp->sc->sc_clkmsk != 0)
-                       *divp = (hp->clkbase / freq) <<
-                           (ffs(hp->sc->sc_clkmsk) - 1);
-               else
-                       *divp = (hp->clkbase / freq) << SDHC_SDCLK_DIV_SHIFT;
-               return true;
+               for (div = 1; div <= 256; div *= 2) {
+                       if ((hp->clkbase / div) <= freq) {
+                               *divp = (div / 2) << SDHC_SDCLK_DIV_SHIFT;
+                               //freq = hp->clkbase / div;
+                               return true;
+                       }
+               }
+               /* No divisor found. */
+               return false;
        }
        /* No divisor found. */
        return false;