| Date | Thu, 17 Sep 2020 13:10:57 +0200 | From | Thierry Reding <> | Subject | Re: [PATCH v7 01/34] i2c: tegra: Make tegra_i2c_flush_fifos() usable in atomic transfer |
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On Wed, Sep 09, 2020 at 01:39:33AM +0300, Dmitry Osipenko wrote: > 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;
Is there are reason why we need reg_offset? Seems to me like we could simplify this, see below.
> + 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;
Why not just:
offset = tegra_i2c_reg_offset(i2c_dev, offset); addr = i2c_dev->base + offset;
or even just:
addr = i2c_dev->base + tegra_i2c_reg_offset(i2c_dev, offset);
? That makes the patch much smaller because you don't have to rewrite the whole variable declaration block and just add the "addr" and "err" variables while removing "timeout".
Thierry [unhandled content-type:application/pgp-signature] |