linux-kernel - [PATCH] phy: renesas: rcar-gen3-usb2: fix SError happen if DEBUG

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Date:   Thu,  9 Jul 2020 19:36:18 +0900
From:   Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
To:     kishon@...com, vkoul@...nel.org
Cc:     wsa+renesas@...g-engineering.com, geert+renesas@...der.be,
        linux-renesas-soc@...r.kernel.org, linux-kernel@...r.kernel.org,
        Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
Subject: [PATCH] phy: renesas: rcar-gen3-usb2: fix SError happen if DEBUG_SHIRQ is enabled

If CONFIG_DEBUG_SHIRQ was enabled, r8a77951-salvator-xs could boot
correctly. If we appended "earlycon keep_bootcon" to the kernel
command like, we could get kernel log like below.

    SError Interrupt on CPU0, code 0xbf000002 -- SError
    CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.8.0-rc3-salvator-x-00505-g6c843129e6faaf01 #785
    Hardware name: Renesas Salvator-X 2nd version board based on r8a77951 (DT)
    pstate: 60400085 (nZCv daIf +PAN -UAO BTYPE=--)
    pc : rcar_gen3_phy_usb2_irq+0x14/0x54
    lr : free_irq+0xf4/0x27c

This means free_irq() calls the interrupt handler while PM runtime
is not getting if DEBUG_SHIRQ is enabled and rcar_gen3_phy_usb2_probe()
failed. To fix the issue, add a condition into the interrupt
handler to avoid register access if any phys are not initialized.

Note that rcar_gen3_is_any_rphy_initialized() was introduced on v5.2.
So, if we backports this patch to v5.1 or less, we need to make
other way.

Reported-by: Wolfram Sang <wsa+renesas@...g-engineering.com>
Reported-by: Geert Uytterhoeven <geert+renesas@...der.be>
Fixes: 9f391c574efc ("phy: rcar-gen3-usb2: add runtime ID/VBUS pin detection")
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
---
 drivers/phy/renesas/phy-rcar-gen3-usb2.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/phy/renesas/phy-rcar-gen3-usb2.c b/drivers/phy/renesas/phy-rcar-gen3-usb2.c
index bfb22f8..91c732d 100644
--- a/drivers/phy/renesas/phy-rcar-gen3-usb2.c
+++ b/drivers/phy/renesas/phy-rcar-gen3-usb2.c
@@ -507,9 +507,13 @@ static irqreturn_t rcar_gen3_phy_usb2_irq(int irq, void *_ch)
 {
 	struct rcar_gen3_chan *ch = _ch;
 	void __iomem *usb2_base = ch->base;
-	u32 status = readl(usb2_base + USB2_OBINTSTA);
+	u32 status;
 	irqreturn_t ret = IRQ_NONE;
 
+	if (!rcar_gen3_is_any_rphy_initialized(ch))
+		return ret;
+
+	status = readl(usb2_base + USB2_OBINTSTA);
 	if (status & USB2_OBINT_BITS) {
 		dev_vdbg(ch->dev, "%s: %08x\n", __func__, status);
 		writel(USB2_OBINT_BITS, usb2_base + USB2_OBINTSTA);
-- 
2.7.4