Re: [PATCH 1/3] MMC compatibility fix - GO_IDLE

[Russell King]

On Sat, Sep 18, 2004 at 11:56:42AM +0200, Pierre Ossman wrote:
> This patch adds a GO_IDLE before sending a new SEND_OP_COND (as required 
> by MMC standard).

Thanks; I haven't completely vanished off the face of the planet.

We already have a function using MMC_GO_IDLE_STATE, so I suggest we
separate this out.  If you need a 1ms delay after sending this, maybe
the other case also needs this delay as well?

How about this patch?

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 PCMCIA      - http://pcmcia.arm.linux.org.uk/
                 2.6 Serial core
diff -u linux-2.6-mmc/drivers/mmc/mmc.c linux/drivers/mmc/mmc.c
--- linux-2.6-mmc/drivers/mmc/mmc.c	Mon Sep 20 10:23:16 2004
+++ linux/drivers/mmc/mmc.c	Wed Sep 22 15:14:00 2004
@@ -451,11 +451,26 @@
 }
 
 /*
+ * Tell attached cards to go to IDLE state
+ */
+static void mmc_idle_cards(struct mmc_host *host)
+{
+	struct mmc_command cmd;
+
+	cmd.opcode = MMC_GO_IDLE_STATE;
+	cmd.arg = 0;
+	cmd.flags = MMC_RSP_NONE;
+
+	mmc_wait_for_cmd(host, &cmd, 0);
+
+	mmc_delay(1);
+}
+
+/*
  * Apply power to the MMC stack.
  */
 static void mmc_power_up(struct mmc_host *host)
 {
-	struct mmc_command cmd;
 	int bit = fls(host->ocr_avail) - 1;
 
 	host->ios.vdd = bit;
@@ -470,12 +485,6 @@
 	host->ops->set_ios(host, &host->ios);
 
 	mmc_delay(2);
-
-	cmd.opcode = MMC_GO_IDLE_STATE;
-	cmd.arg = 0;
-	cmd.flags = MMC_RSP_NONE;
-
-	mmc_wait_for_cmd(host, &cmd, 0);
 }
 
 static void mmc_power_off(struct mmc_host *host)
@@ -647,12 +656,22 @@
 		u32 ocr;
 
 		mmc_power_up(host);
+		mmc_idle_cards(host);
 
 		err = mmc_send_op_cond(host, 0, &ocr);
 		if (err != MMC_ERR_NONE)
 			return;
 
 		host->ocr = mmc_select_voltage(host, ocr);
+
+		/*
+		 * Since we're changing the OCR value, we seem to
+		 * need to tell some cards to go back to the idle
+		 * state.  We wait 1ms to give cards time to
+		 * respond.
+		 */
+		if (host->ocr)
+			mmc_idle_cards(host);
 	} else {
 		host->ios.bus_mode = MMC_BUSMODE_OPENDRAIN;
 		host->ios.clock = host->f_min;