[PATCH v6 01/35] i2c: tegra: Make tegra_i2c_flush_fifos() usable in atomic transfer
From: Dmitry Osipenko <digetx@gmail.com>
Date: 2020-09-08 02:12:49
Also in:
linux-tegra, lkml
Subsystem:
i2c subsystem, i2c subsystem host drivers, tegra i2c driver, the rest · Maintainers:
Wolfram Sang, Andi Shyti, Laxman Dewangan, Linus Torvalds
The tegra_i2c_flush_fifos() shouldn't sleep in atomic transfer and jiffies are not updating if interrupts are disabled. Let's switch to use iopoll API helpers for register-polling. The iopoll API provides helpers for both atomic and non-atomic cases. Note that this patch doesn't fix any known problem because normally FIFO is flushed at the time of starting a new transfer. Reviewed-by: Michał Mirosław <mirq-linux@rere.qmqm.pl> Signed-off-by: Dmitry Osipenko <digetx@gmail.com> --- drivers/i2c/busses/i2c-tegra.c | 25 ++++++++++++++++--------- 1 file changed, 16 insertions(+), 9 deletions(-)
diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 00d3e4d7a01e..ab88cdd70376 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c@@ -470,9 +470,9 @@ static int tegra_i2c_init_dma(struct tegra_i2c_dev *i2c_dev) static int tegra_i2c_flush_fifos(struct tegra_i2c_dev *i2c_dev) { - unsigned long timeout = jiffies + HZ; - unsigned int offset; - u32 mask, val; + u32 mask, val, offset, reg_offset; + void __iomem *addr; + int err; if (i2c_dev->hw->has_mst_fifo) { mask = I2C_MST_FIFO_CONTROL_TX_FLUSH |
@@ -488,12 +488,19 @@ static int tegra_i2c_flush_fifos(struct tegra_i2c_dev *i2c_dev) val |= mask; i2c_writel(i2c_dev, val, offset); - while (i2c_readl(i2c_dev, offset) & mask) { - if (time_after(jiffies, timeout)) { - dev_warn(i2c_dev->dev, "timeout waiting for fifo flush\n"); - return -ETIMEDOUT; - } - usleep_range(1000, 2000); + reg_offset = tegra_i2c_reg_addr(i2c_dev, offset); + addr = i2c_dev->base + reg_offset; + + if (i2c_dev->is_curr_atomic_xfer) + err = readl_relaxed_poll_timeout_atomic(addr, val, !(val & mask), + 1000, 1000000); + else + err = readl_relaxed_poll_timeout(addr, val, !(val & mask), + 1000, 1000000); + + if (err) { + dev_err(i2c_dev->dev, "failed to flush FIFO\n"); + return err; } return 0; }
--
2.27.0