patch "usb: renesas_usbhs: fix clearing the {BRDY,BEMP}STS condition" added to usb-linus

This is a note to let you know that I've just added the patch titled

usb: renesas_usbhs: fix clearing the {BRDY,BEMP}STS condition

to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From: Yoshihiro Shimoda <[email protected]>
Date: Mon, 29 Aug 2016 18:00:38 +0900
Subject: usb: renesas_usbhs: fix clearing the {BRDY,BEMP}STS condition

The previous driver is possible to stop the transfer wrongly. For example:
1) An interrupt happens, but not BRDY interruption.
2) Read INTSTS0. And than state->intsts0 is not set to BRDY.
3) BRDY is set to 1 here.
4) Read BRDYSTS.
5) Clear the BRDYSTS. And then. the BRDY is cleared wrongly.

Remarks:
- The INTSTS0.BRDY is read only.
- If any bits of BRDYSTS are set to 1, the BRDY is set to 1.
- If BRDYSTS is 0, the BRDY is set to 0.

So, this patch adds condition to avoid such situation. (And about NRDYSTS, this is not used for now. But, avoiding any side effects, this patch doesn't touch it.)

---
 drivers/usb/renesas_usbhs/mod.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

index d4be5d594896..28965ef4f824 100644
@@ -282,9 +282,16 @@ static irqreturn_t usbhs_interrupt(int irq, void *data)
 	if (usbhs_mod_is_host(priv))
 		usbhs_write(priv, INTSTS1, ~irq_state.intsts1 & INTSTS1_MAGIC);
 
-	usbhs_write(priv, BRDYSTS, ~irq_state.brdysts);
+	/*
+	 * The driver should not clear the xxxSTS after the line of
+	 * "call irq callback functions" because each "if" statement is
+	 * possible to call the callback function for avoiding any side effects.
+	 */
+	if (irq_state.intsts0 & BRDY)
+		usbhs_write(priv, BRDYSTS, ~irq_state.brdysts);
 	usbhs_write(priv, NRDYSTS, ~irq_state.nrdysts);
-	usbhs_write(priv, BEMPSTS, ~irq_state.bempsts);
+	if (irq_state.intsts0 & BEMP)
+		usbhs_write(priv, BEMPSTS, ~irq_state.bempsts);
 
 	/*
 	 * call irq callback functions

2.9.3