From eaba68785c2d24ebf1f0d46c24e11b79cc2f94c7 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 16 Oct 2018 12:01:49 +0900 Subject: [PATCH] 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 Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-uniphier-f.c | 11 ++++++----- 1 file 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 @@ static irqreturn_t uniphier_fi2c_interrupt(int irq, void *dev_id) } 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 */ -- GitLab