[PATCH 1/3] MMC compatibility fix - GO_IDLE

[PATCH 1/3] MMC compatibility fix - GO_IDLE

[Pierre Ossman]

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This patch adds a GO_IDLE before sending a new SEND_OP_COND (as required 
by MMC standard).

[-- Attachment #2: mmc-goidle.patch --]
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Index: linux-wbsd/drivers/mmc/mmc.c
===================================================================
--- linux-wbsd/drivers/mmc/mmc.c	(revision 57)
+++ linux-wbsd/drivers/mmc/mmc.c	(revision 58)
@@ -579,6 +579,8 @@
 
 static void mmc_setup(struct mmc_host *host)
 {
+	struct mmc_command cmd;
+	
 	if (host->ios.power_mode != MMC_POWER_ON) {
 		int err;
 		u32 ocr;
@@ -613,6 +615,16 @@
 	if (host->ocr == 0)
 		return;
 
+	/* Put cards in idle before sending new OCR */
+
+	cmd.opcode = MMC_GO_IDLE_STATE;
+	cmd.arg = 0;
+	cmd.flags = MMC_RSP_NONE;
+	
+	mmc_wait_for_cmd(host, &cmd, 0);
+
+	mmc_delay(1);
+	
 	/*
 	 * Send the selected OCR multiple times... until the cards
 	 * all get the idea that they should be ready for CMD2.

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

[Russell King]

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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

[-- Attachment #2: mmc-idlecards.diff --]
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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;

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

[Pierre Ossman]

Russell King wrote:

>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.
>  
>
Good to know. You've seemed a bit busy :)

>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?
>
>  
>
The delay was added just in case. The cards I have here work fine 
without it. I just thought adding a small delay might avoid problematic 
cards later on. Seems to be a few of those.

>How about this patch?
>
>  
>
Looks ok. You sure we don't need to put all cards into an idle state 
before issuing a new SEND_OP_COND? I haven't studied how the MMC layer 
is called in detail. Can a rescan be done while a card is in a selected 
state?

Rgds
Pierre

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

[Russell King]

On Wed, Sep 22, 2004 at 07:45:35PM +0200, Pierre Ossman wrote:
> Russell King wrote:
> >How about this patch?
>
> Looks ok. You sure we don't need to put all cards into an idle state 
> before issuing a new SEND_OP_COND?

We aren't sending that to the existing cards - they are still in
whatever state they were when they were previously detected.  In
addition, we aren't actually changing or detecting the operational
conditions, we're merely informing the new cards about the existing
setup.

> Can a rescan be done while a card is in a selected state?

Yes - any cards not already in idle state will ignore the command
as intended.

-- 
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