svn commit: r254427 - head/sys/dev/mmc

[Ian Lepore]

Author: ian
Date: Fri Aug 16 20:32:56 2013
New Revision: 254427
URL: http://svnweb.freebsd.org/changeset/base/254427

Log:
  During card identification, run the bus at 400KHz, not the minimum
  speed the bus claims to be capable of.  The 400KHz speed is dictated
  by the SD and MMC standards.

Modified:
  head/sys/dev/mmc/mmc.c

Modified: head/sys/dev/mmc/mmc.c
==============================================================================
--- head/sys/dev/mmc/mmc.c	Fri Aug 16 20:24:41 2013	(r254426)
+++ head/sys/dev/mmc/mmc.c	Fri Aug 16 20:32:56 2013	(r254427)
@@ -106,6 +106,8 @@ struct mmc_ivars {
 
 #define CMD_RETRIES	3
 
+#define	CARD_ID_FREQUENCY 400000 /* Spec requires 400KHz max during ID phase. */
+
 static SYSCTL_NODE(_hw, OID_AUTO, mmc, CTLFLAG_RD, NULL, "mmc driver");
 
 static int mmc_debug;
@@ -579,7 +581,7 @@ mmc_power_up(struct mmc_softc *sc)
 	mmcbr_update_ios(dev);
 	mmc_ms_delay(1);
 
-	mmcbr_set_clock(dev, mmcbr_get_f_min(sc->dev));
+	mmcbr_set_clock(dev, CARD_ID_FREQUENCY);
 	mmcbr_set_timing(dev, bus_timing_normal);
 	mmcbr_set_power_mode(dev, power_on);
 	mmcbr_update_ios(dev);
@@ -1534,7 +1536,7 @@ mmc_go_discovery(struct mmc_softc *sc)
 			mmc_idle_cards(sc);
 	} else {
 		mmcbr_set_bus_mode(dev, opendrain);
-		mmcbr_set_clock(dev, mmcbr_get_f_min(dev));
+		mmcbr_set_clock(dev, CARD_ID_FREQUENCY);
 		mmcbr_update_ios(dev);
 		/* XXX recompute vdd based on new cards? */
 	}
@@ -1572,11 +1574,10 @@ static int
 mmc_calculate_clock(struct mmc_softc *sc)
 {
 	int max_dtr, max_hs_dtr, max_timing;
-	int nkid, i, f_min, f_max;
+	int nkid, i, f_max;
 	device_t *kids;
 	struct mmc_ivars *ivar;
 	
-	f_min = mmcbr_get_f_min(sc->dev);
 	f_max = mmcbr_get_f_max(sc->dev);
 	max_dtr = max_hs_dtr = f_max;
 	if ((mmcbr_get_caps(sc->dev) & MMC_CAP_HSPEED))