* [PATCH] i2c: tegra: Wait for config load atomically while in ISR
@ 2021-01-11 13:55 Mikko Perttunen
2021-01-11 14:31 ` David Laight
2021-01-11 15:14 ` Dmitry Osipenko
0 siblings, 2 replies; 5+ messages in thread
From: Mikko Perttunen @ 2021-01-11 13:55 UTC (permalink / raw)
To: ldewangan, digetx, thierry.reding, jonathanh, wsa
Cc: linux-i2c, linux-tegra, linux-kernel, Mikko Perttunen, stable
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;
--
2.30.0
^ permalink raw reply related [flat|nested] 5+ messages in thread* RE: [PATCH] i2c: tegra: Wait for config load atomically while in ISR
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
1 sibling, 1 reply; 5+ messages in thread
From: David Laight @ 2021-01-11 14:31 UTC (permalink / raw)
To: 'Mikko Perttunen',
ldewangan, digetx, thierry.reding, jonathanh, wsa
Cc: linux-i2c, linux-tegra, linux-kernel, stable
From: Mikko Perttunen
> Sent: 11 January 2021 13:56
>
> 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.
Spin-waiting in an ISR for anything that it makes sense to do
a sleep-wait for at other times is badly broken design.
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] i2c: tegra: Wait for config load atomically while in ISR
2021-01-11 14:31 ` David Laight
@ 2021-01-11 14:38 ` Mikko Perttunen
0 siblings, 0 replies; 5+ messages in thread
From: Mikko Perttunen @ 2021-01-11 14:38 UTC (permalink / raw)
To: David Laight, 'Mikko Perttunen',
ldewangan, digetx, thierry.reding, jonathanh, wsa
Cc: linux-i2c, linux-tegra, linux-kernel, stable
Agreed that this is possibly not optimal, but this patch simply returns
the behavior to what it was before "i2c: tegra: Support atomic
transfers", fixing the overt issue.
Design fixes can be considered later, in a non-stable patch.
Mikko
On 1/11/21 4:31 PM, David Laight wrote:
> From: Mikko Perttunen
>> Sent: 11 January 2021 13:56
>>
>> 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.
>
> Spin-waiting in an ISR for anything that it makes sense to do
> a sleep-wait for at other times is badly broken design.
>
> David
>
> -
> Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
> Registration No: 1397386 (Wales)
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] i2c: tegra: Wait for config load atomically while in ISR
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 15:14 ` Dmitry Osipenko
2021-01-11 15:52 ` Mikko Perttunen
1 sibling, 1 reply; 5+ messages in thread
From: Dmitry Osipenko @ 2021-01-11 15:14 UTC (permalink / raw)
To: Mikko Perttunen, ldewangan, thierry.reding, jonathanh, wsa
Cc: linux-i2c, linux-tegra, linux-kernel, stable
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);
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH] i2c: tegra: Wait for config load atomically while in ISR
2021-01-11 15:14 ` Dmitry Osipenko
@ 2021-01-11 15:52 ` Mikko Perttunen
0 siblings, 0 replies; 5+ messages in thread
From: Mikko Perttunen @ 2021-01-11 15:52 UTC (permalink / raw)
To: Dmitry Osipenko, Mikko Perttunen, ldewangan, thierry.reding,
jonathanh, wsa
Cc: linux-i2c, linux-tegra, linux-kernel, stable
On 1/11/21 5:14 PM, Dmitry Osipenko wrote:
> 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);
>
Yep, I'll post a v2 with that.
Mikko
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2021-01-11 15:53 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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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
2021-01-11 15:52 ` Mikko Perttunen
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