Author: kan
Date: Wed Dec 28 19:40:59 2016
New Revision: 310722
URL: https://svnweb.freebsd.org/changeset/base/310722

Log:
  Do not use read-modify-write on MSC control register.
  
  The register is write-only, so just write only bits we want.
  
  Submitted by: jmcneill

Modified:
  head/sys/mips/ingenic/jz4780_mmc.c

Modified: head/sys/mips/ingenic/jz4780_mmc.c
==============================================================================
--- head/sys/mips/ingenic/jz4780_mmc.c  Wed Dec 28 18:42:43 2016        
(r310721)
+++ head/sys/mips/ingenic/jz4780_mmc.c  Wed Dec 28 19:40:59 2016        
(r310722)
@@ -412,13 +412,9 @@ static int
 jz4780_mmc_reset(struct jz4780_mmc_softc *sc)
 {
        int timeout;
-       int reg;
 
        /* Stop the clock */
-       reg = JZ_MMC_READ_4(sc, JZ_MSC_CTRL);
-       reg &= ~(JZ_CLOCK_CTRL_M);
-       reg |= JZ_CLOCK_STOP;
-       JZ_MMC_WRITE_4(sc, JZ_MSC_CTRL, reg);
+       JZ_MMC_WRITE_4(sc, JZ_MSC_CTRL, JZ_CLOCK_STOP);
 
        timeout = 1000;
        while (--timeout > 0) {
@@ -432,9 +428,7 @@ jz4780_mmc_reset(struct jz4780_mmc_softc
        }
 
        /* Reset */
-       reg = JZ_MMC_READ_4(sc, JZ_MSC_CTRL);
-       reg |= JZ_RESET;
-       JZ_MMC_WRITE_4(sc, JZ_MSC_CTRL, reg);
+       JZ_MMC_WRITE_4(sc, JZ_MSC_CTRL, JZ_RESET);
 
        timeout = 10;
        while (--timeout > 0) {
@@ -647,7 +641,7 @@ jz4780_mmc_request(device_t bus, device_
 {
        struct jz4780_mmc_softc *sc;
        struct mmc_command *cmd;
-       uint32_t cmdat, ctrl, iwait;
+       uint32_t cmdat, iwait;
        int blksz;
 
        sc = device_get_softc(bus);
@@ -731,9 +725,7 @@ jz4780_mmc_request(device_t bus, device_
        JZ_MMC_WRITE_4(sc, JZ_MSC_CMD, cmd->opcode);
        JZ_MMC_WRITE_4(sc, JZ_MSC_CMDAT, cmdat);
 
-       ctrl = JZ_MMC_READ_4(sc, JZ_MSC_CTRL);
-       ctrl |= JZ_START_OP | JZ_CLOCK_START;
-       JZ_MMC_WRITE_4(sc, JZ_MSC_CTRL, ctrl);
+       JZ_MMC_WRITE_4(sc, JZ_MSC_CTRL, JZ_START_OP | JZ_CLOCK_START);
 
        callout_reset(&sc->sc_timeoutc, sc->sc_timeout * hz,
            jz4780_mmc_timeout, sc);
@@ -853,8 +845,7 @@ jz4780_mmc_disable_clock(struct jz4780_m
 {
        int timeout;
 
-       JZ_MMC_WRITE_4(sc, JZ_MSC_CTRL,
-           JZ_MMC_READ_4(sc, JZ_MSC_CTRL) | JZ_CLOCK_STOP);
+       JZ_MMC_WRITE_4(sc, JZ_MSC_CTRL, JZ_CLOCK_STOP);
 
        for (timeout = 1000; timeout > 0; timeout--)
                if ((JZ_MMC_READ_4(sc, JZ_MSC_STAT) & JZ_CLK_EN) == 0)
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