From: Alexander Shishkin Date: Tue, 11 May 2010 18:35:17 +0000 (-0700) Subject: omap: i2c: add a timeout to the busy waiting X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=e9f59b9c9bc5730152b6a94c47dd90b730a07e35;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git omap: i2c: add a timeout to the busy waiting The errata 1.153 workaround is busy waiting on XUDF bit in interrupt context, which may lead to kernel hangs. The problem can be reproduced by running the bus with wrong (too high) speed. Signed-off-by: Alexander Shishkin Signed-off-by: Tony Lindgren Signed-off-by: Ben Dooks --- diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c index ef73483efb84..00fd02ec1b65 100644 --- a/drivers/i2c/busses/i2c-omap.c +++ b/drivers/i2c/busses/i2c-omap.c @@ -763,17 +763,25 @@ omap_i2c_rev1_isr(int this_irq, void *dev_id) */ static int errata_omap3_1p153(struct omap_i2c_dev *dev, u16 *stat, int *err) { - while (!(*stat & OMAP_I2C_STAT_XUDF)) { + unsigned long timeout = 10000; + + while (--timeout && !(*stat & OMAP_I2C_STAT_XUDF)) { if (*stat & (OMAP_I2C_STAT_NACK | OMAP_I2C_STAT_AL)) { omap_i2c_ack_stat(dev, *stat & (OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR)); *err |= OMAP_I2C_STAT_XUDF; return -ETIMEDOUT; } + cpu_relax(); *stat = omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG); } + if (!timeout) { + dev_err(dev->dev, "timeout waiting on XUDF bit\n"); + return 0; + } + return 0; }