From: Dmitry Osipenko <digetx@gmail.com>
To: Mikko Perttunen <mperttunen@nvidia.com>,
ldewangan@nvidia.com, thierry.reding@gmail.com,
jonathanh@nvidia.com, wsa@kernel.org
Cc: linux-i2c@vger.kernel.org, linux-tegra@vger.kernel.org,
linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH] i2c: tegra: Wait for config load atomically while in ISR
Date: Mon, 11 Jan 2021 18:14:58 +0300 [thread overview]
Message-ID: <b7f69fb9-2960-f994-51d8-afd86af26bba@gmail.com> (raw)
In-Reply-To: <20210111135547.3613092-1-mperttunen@nvidia.com>
11.01.2021 16:55, Mikko Perttunen пишет:
> Upon a communication error, the interrupt handler can call
> tegra_i2c_disable_packet_mode. This causes a sleeping poll to happen
> unless the current transaction was marked atomic. Since
> tegra_i2c_disable_packet_mode is only called from the interrupt path,
> make it use atomic waiting always.
>
> Fixes: ede2299f7101 ("i2c: tegra: Support atomic transfers")
> Cc: stable@vger.kernel.org
> Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
> ---
> This fixes constant spew for me while HDMI is connected to a
> powered off television.
>
> drivers/i2c/busses/i2c-tegra.c | 16 ++++++++--------
> 1 file changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
> index 6f08c0c3238d..4a7ff1840565 100644
> --- a/drivers/i2c/busses/i2c-tegra.c
> +++ b/drivers/i2c/busses/i2c-tegra.c
> @@ -528,12 +528,12 @@ static void tegra_i2c_vi_init(struct tegra_i2c_dev *i2c_dev)
>
> static int tegra_i2c_poll_register(struct tegra_i2c_dev *i2c_dev,
> u32 reg, u32 mask, u32 delay_us,
> - u32 timeout_us)
> + u32 timeout_us, bool force_atomic)
> {
> void __iomem *addr = i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg);
> u32 val;
>
> - if (!i2c_dev->atomic_mode)
> + if (!i2c_dev->atomic_mode && !force_atomic)
> return readl_relaxed_poll_timeout(addr, val, !(val & mask),
> delay_us, timeout_us);
>
> @@ -560,7 +560,7 @@ static int tegra_i2c_flush_fifos(struct tegra_i2c_dev *i2c_dev)
> val |= mask;
> i2c_writel(i2c_dev, val, offset);
>
> - err = tegra_i2c_poll_register(i2c_dev, offset, mask, 1000, 1000000);
> + err = tegra_i2c_poll_register(i2c_dev, offset, mask, 1000, 1000000, false);
> if (err) {
> dev_err(i2c_dev->dev, "failed to flush FIFO\n");
> return err;
> @@ -569,7 +569,7 @@ static int tegra_i2c_flush_fifos(struct tegra_i2c_dev *i2c_dev)
> return 0;
> }
>
> -static int tegra_i2c_wait_for_config_load(struct tegra_i2c_dev *i2c_dev)
> +static int tegra_i2c_wait_for_config_load(struct tegra_i2c_dev *i2c_dev, bool force_atomic)
> {
> int err;
>
> @@ -579,7 +579,7 @@ static int tegra_i2c_wait_for_config_load(struct tegra_i2c_dev *i2c_dev)
> i2c_writel(i2c_dev, I2C_MSTR_CONFIG_LOAD, I2C_CONFIG_LOAD);
>
> err = tegra_i2c_poll_register(i2c_dev, I2C_CONFIG_LOAD, 0xffffffff,
> - 1000, I2C_CONFIG_LOAD_TIMEOUT);
> + 1000, I2C_CONFIG_LOAD_TIMEOUT, force_atomic);
> if (err) {
> dev_err(i2c_dev->dev, "failed to load config\n");
> return err;
> @@ -684,7 +684,7 @@ static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
> if (i2c_dev->multimaster_mode && i2c_dev->hw->has_slcg_override_reg)
> i2c_writel(i2c_dev, I2C_MST_CORE_CLKEN_OVR, I2C_CLKEN_OVERRIDE);
>
> - err = tegra_i2c_wait_for_config_load(i2c_dev);
> + err = tegra_i2c_wait_for_config_load(i2c_dev, false);
> if (err)
> return err;
>
> @@ -707,7 +707,7 @@ static int tegra_i2c_disable_packet_mode(struct tegra_i2c_dev *i2c_dev)
> if (cnfg & I2C_CNFG_PACKET_MODE_EN)
> i2c_writel(i2c_dev, cnfg & ~I2C_CNFG_PACKET_MODE_EN, I2C_CNFG);
>
> - return tegra_i2c_wait_for_config_load(i2c_dev);
> + return tegra_i2c_wait_for_config_load(i2c_dev, true);
> }
>
> static int tegra_i2c_empty_rx_fifo(struct tegra_i2c_dev *i2c_dev)
> @@ -1090,7 +1090,7 @@ static int tegra_i2c_issue_bus_clear(struct i2c_adapter *adap)
> I2C_BC_TERMINATE;
> i2c_writel(i2c_dev, val, I2C_BUS_CLEAR_CNFG);
>
> - err = tegra_i2c_wait_for_config_load(i2c_dev);
> + err = tegra_i2c_wait_for_config_load(i2c_dev, false);
> if (err)
> return err;
>
>
What about a simpler variant:
diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 6f08c0c3238d..0727383f4940 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -533,7 +533,7 @@ static int tegra_i2c_poll_register(struct
tegra_i2c_dev *i2c_dev,
void __iomem *addr = i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg);
u32 val;
- if (!i2c_dev->atomic_mode)
+ if (!i2c_dev->atomic_mode && !in_irq())
return readl_relaxed_poll_timeout(addr, val, !(val & mask),
delay_us, timeout_us);
next prev parent reply other threads:[~2021-01-11 15:16 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-11 13:55 [PATCH] i2c: tegra: Wait for config load atomically while in ISR Mikko Perttunen
2021-01-11 14:31 ` David Laight
2021-01-11 14:38 ` Mikko Perttunen
2021-01-11 15:14 ` Dmitry Osipenko [this message]
2021-01-11 15:52 ` Mikko Perttunen
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