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authorMasahiro Yamada <yamada.masahiro@socionext.com>2018-10-16 12:01:49 +0900
committerWolfram Sang <wsa@the-dreams.de>2018-10-29 18:53:37 +0000
commiteaba68785c2d24ebf1f0d46c24e11b79cc2f94c7 (patch)
tree934fcac325c5fcac927b0c5b1ded7965a02a859f
parent39226aaa85f002d695e3cafade3309e12ffdaecd (diff)
download96b-common-eaba68785c2d24ebf1f0d46c24e11b79cc2f94c7.tar.gz
i2c: uniphier-f: fix race condition when IRQ is cleared
The current IRQ handler clears all the IRQ status bits when it bails out. This is dangerous because it might clear away the status bits that have just been set while processing the current handler. If this happens, the IRQ event for the latest transfer is lost forever. The IRQ status bits must be cleared *before* the next transfer is kicked. Fixes: 6a62974b667f ("i2c: uniphier_f: add UniPhier FIFO-builtin I2C driver") Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
-rw-r--r--drivers/i2c/busses/i2c-uniphier-f.c11
1 files changed, 6 insertions, 5 deletions
diff --git a/drivers/i2c/busses/i2c-uniphier-f.c b/drivers/i2c/busses/i2c-uniphier-f.c
index 067715305976..dd384743dbbd 100644
--- a/drivers/i2c/busses/i2c-uniphier-f.c
+++ b/drivers/i2c/busses/i2c-uniphier-f.c
@@ -143,9 +143,10 @@ static void uniphier_fi2c_set_irqs(struct uniphier_fi2c_priv *priv)
writel(priv->enabled_irqs, priv->membase + UNIPHIER_FI2C_IE);
}
-static void uniphier_fi2c_clear_irqs(struct uniphier_fi2c_priv *priv)
+static void uniphier_fi2c_clear_irqs(struct uniphier_fi2c_priv *priv,
+ u32 mask)
{
- writel(-1, priv->membase + UNIPHIER_FI2C_IC);
+ writel(mask, priv->membase + UNIPHIER_FI2C_IC);
}
static void uniphier_fi2c_stop(struct uniphier_fi2c_priv *priv)
@@ -172,6 +173,8 @@ static irqreturn_t uniphier_fi2c_interrupt(int irq, void *dev_id)
"interrupt: enabled_irqs=%04x, irq_status=%04x\n",
priv->enabled_irqs, irq_status);
+ uniphier_fi2c_clear_irqs(priv, irq_status);
+
if (irq_status & UNIPHIER_FI2C_INT_STOP)
goto complete;
@@ -250,8 +253,6 @@ complete:
}
handled:
- uniphier_fi2c_clear_irqs(priv);
-
spin_unlock(&priv->lock);
return IRQ_HANDLED;
@@ -340,7 +341,7 @@ static int uniphier_fi2c_master_xfer_one(struct i2c_adapter *adap,
priv->flags |= UNIPHIER_FI2C_STOP;
reinit_completion(&priv->comp);
- uniphier_fi2c_clear_irqs(priv);
+ uniphier_fi2c_clear_irqs(priv, U32_MAX);
writel(UNIPHIER_FI2C_RST_TBRST | UNIPHIER_FI2C_RST_RBRST,
priv->membase + UNIPHIER_FI2C_RST); /* reset TX/RX FIFO */