[rt2x00-users] [PATCH] Fix 'Error - MCU request failed' during initialization

[Jakub Kicinski]

Hello!

I post my humble attempt to get rid of notorious Error - MCU request
failed ;)

I tried to fully mimic legacy driver, which should explain some obscure
moves like putting device to sleep and waking it up immediately.

Also during the work I earned some understanding of MCU requests and
found some info on arguments. Would you like me to share it or perhaps
add some documentation to header files?

The rt2800pci_set_state function got somehow lost during development
and I decided not to recreate it since it feels a little confusing to
me. Although note that behaviour for STATE_DEEP_SLEEP and STATE_STANDBY
will change. Previously transitions to those states were forwarded to
rt2800pci_set_state and ignored there. Now they will be treated the
same as STATE_SLEEP. In practice though, it shouldn't change behaviour
since mentioned states are not used in rt2800.

I have tested this on my only PCI device (rt: 2860, rf: 0001, rev:
0102). Please post your comments and possibly give it more testing on
your devices.

---
Bring MCU operations during device initialization to sync with legacy
driver.

This should fix following error:
phy0 -> rt2800pci_mcu_status: Error - MCU request failed, no response
from hardware

Signed-off-by: Jakub Kicinski <kubakici at wp.pl>
---
 drivers/net/wireless/rt2x00/rt2800.h    |    4 ++-
 drivers/net/wireless/rt2x00/rt2800pci.c |   50 +++++++++++++++----------------
 2 files changed, 27 insertions(+), 27 deletions(-)

diff --git a/drivers/net/wireless/rt2x00/rt2800.h b/drivers/net/wireless/rt2x00/rt2800.h
index 2571a2f..2a37373 100644
--- a/drivers/net/wireless/rt2x00/rt2800.h
+++ b/drivers/net/wireless/rt2x00/rt2800.h
@@ -2279,7 +2279,9 @@ struct mac_iveiv_entry {
 /*
  * MCU mailbox tokens
  */
-#define TOKEN_WAKUP			3
+#define TOKEN_SLEEP			1
+#define TOKEN_RADIO_OFF			2
+#define TOKEN_WAKEUP			3
 
 /*
  * DMA descriptor defines.
diff --git a/drivers/net/wireless/rt2x00/rt2800pci.c b/drivers/net/wireless/rt2x00/rt2800pci.c
index 4941a1a..8ceda61 100644
--- a/drivers/net/wireless/rt2x00/rt2800pci.c
+++ b/drivers/net/wireless/rt2x00/rt2800pci.c
@@ -529,23 +529,6 @@ static void rt2800pci_disable_radio(struct rt2x00_dev *rt2x00dev)
 	}
 }
 
-static int rt2800pci_set_state(struct rt2x00_dev *rt2x00dev,
-			       enum dev_state state)
-{
-	if (state == STATE_AWAKE) {
-		rt2800_mcu_request(rt2x00dev, MCU_WAKEUP, TOKEN_WAKUP, 0, 0x02);
-		rt2800pci_mcu_status(rt2x00dev, TOKEN_WAKUP);
-	} else if (state == STATE_SLEEP) {
-		rt2x00pci_register_write(rt2x00dev, H2M_MAILBOX_STATUS,
-					 0xffffffff);
-		rt2x00pci_register_write(rt2x00dev, H2M_MAILBOX_CID,
-					 0xffffffff);
-		rt2800_mcu_request(rt2x00dev, MCU_SLEEP, 0x01, 0xff, 0x01);
-	}
-
-	return 0;
-}
-
 static int rt2800pci_set_device_state(struct rt2x00_dev *rt2x00dev,
 				      enum dev_state state)
 {
@@ -553,14 +536,20 @@ static int rt2800pci_set_device_state(struct rt2x00_dev *rt2x00dev,
 
 	switch (state) {
 	case STATE_RADIO_ON:
-		/*
-		 * Before the radio can be enabled, the device first has
-		 * to be woken up. After that it needs a bit of time
-		 * to be fully awake and then the radio can be enabled.
-		 */
-		rt2800pci_set_state(rt2x00dev, STATE_AWAKE);
-		msleep(1);
+		/* Initialise all registers and send MCU_BOOT_SIGNAL. */
 		retval = rt2800pci_enable_radio(rt2x00dev);
+
+		/* After resume MCU_BOOT_SIGNAL will trash those. */
+		rt2x00pci_register_write(rt2x00dev, H2M_MAILBOX_STATUS, ~0);
+		rt2x00pci_register_write(rt2x00dev, H2M_MAILBOX_CID, ~0);
+
+		/* Finish initialization procedure. */
+		rt2800_mcu_request(rt2x00dev, MCU_SLEEP, TOKEN_RADIO_OFF,
+				   0xff, 0x02);
+		rt2800pci_mcu_status(rt2x00dev, TOKEN_RADIO_OFF);
+
+		rt2800_mcu_request(rt2x00dev, MCU_WAKEUP, TOKEN_WAKEUP, 0, 0);
+		rt2800pci_mcu_status(rt2x00dev, TOKEN_WAKEUP);
 		break;
 	case STATE_RADIO_OFF:
 		/*
@@ -568,7 +557,7 @@ static int rt2800pci_set_device_state(struct rt2x00_dev *rt2x00dev,
 		 * be put to sleep for powersaving.
 		 */
 		rt2800pci_disable_radio(rt2x00dev);
-		rt2800pci_set_state(rt2x00dev, STATE_SLEEP);
+		rt2800pci_set_device_state(rt2x00dev, STATE_SLEEP);
 		break;
 	case STATE_RADIO_IRQ_ON:
 	case STATE_RADIO_IRQ_OFF:
@@ -577,8 +566,17 @@ static int rt2800pci_set_device_state(struct rt2x00_dev *rt2x00dev,
 	case STATE_DEEP_SLEEP:
 	case STATE_SLEEP:
 	case STATE_STANDBY:
+		/* PCIe devices won't report status after SLEEP request. */
+		rt2x00pci_register_write(rt2x00dev, H2M_MAILBOX_STATUS, ~0);
+		rt2x00pci_register_write(rt2x00dev, H2M_MAILBOX_CID, ~0);
+		rt2800_mcu_request(rt2x00dev, MCU_SLEEP, TOKEN_SLEEP,
+				   0xff, 0x01);
+		break;
 	case STATE_AWAKE:
-		retval = rt2800pci_set_state(rt2x00dev, state);
+		/* Autowakeup configuration should be cleared by the caller. */
+		rt2800_mcu_request(rt2x00dev, MCU_WAKEUP, TOKEN_WAKEUP,
+				   0, 0x02);
+		rt2800pci_mcu_status(rt2x00dev, TOKEN_WAKEUP);
 		break;
 	default:
 		retval = -ENOTSUPP;