* [PATCH 0/2] stm32 usart improve DMA probe
@ 2021-05-27 9:15 Erwan Le Ray
2021-05-27 9:15 ` [PATCH 1/2] serial: stm32: reset dma buffers during probe Erwan Le Ray
2021-05-27 9:15 ` [PATCH 2/2] serial: stm32: defer probe for dma devices Erwan Le Ray
0 siblings, 2 replies; 6+ messages in thread
From: Erwan Le Ray @ 2021-05-27 9:15 UTC (permalink / raw)
To: Greg Kroah-Hartman, Jiri Slaby, Maxime Coquelin, Alexandre Torgue
Cc: linux-serial, linux-stm32, linux-arm-kernel, linux-kernel,
Erwan Le Ray, Fabrice Gasnier, Valentin Caron, Amelie Delaunay
This series improves DMA probe.
Erwan Le Ray (2):
serial: stm32: reset dma buffers during probe
serial: stm32: defer probe for dma devices
drivers/tty/serial/stm32-usart.c | 165 +++++++++++++++----------------
1 file changed, 79 insertions(+), 86 deletions(-)
--
2.17.1
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 1/2] serial: stm32: reset dma buffers during probe
2021-05-27 9:15 [PATCH 0/2] stm32 usart improve DMA probe Erwan Le Ray
@ 2021-05-27 9:15 ` Erwan Le Ray
2021-05-27 9:49 ` Greg Kroah-Hartman
2021-05-27 9:15 ` [PATCH 2/2] serial: stm32: defer probe for dma devices Erwan Le Ray
1 sibling, 1 reply; 6+ messages in thread
From: Erwan Le Ray @ 2021-05-27 9:15 UTC (permalink / raw)
To: Greg Kroah-Hartman, Jiri Slaby, Maxime Coquelin, Alexandre Torgue
Cc: linux-serial, linux-stm32, linux-arm-kernel, linux-kernel,
Erwan Le Ray, Fabrice Gasnier, Valentin Caron, Amelie Delaunay
Reset Rx and Tx dma buffers during probe to avoid freeing
invalid buffer in no dma mode.
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index c2ae7b392b86..2ac3b30477a7 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -1168,6 +1168,8 @@ static struct stm32_port *stm32_usart_of_get_port(struct platform_device *pdev)
stm32_ports[id].cr1_irq = USART_CR1_RXNEIE;
stm32_ports[id].cr3_irq = 0;
stm32_ports[id].last_res = RX_BUF_L;
+ stm32_ports[id].rx_dma_buf = 0;
+ stm32_ports[id].tx_dma_buf = 0;
return &stm32_ports[id];
}
--
2.17.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 2/2] serial: stm32: defer probe for dma devices
2021-05-27 9:15 [PATCH 0/2] stm32 usart improve DMA probe Erwan Le Ray
2021-05-27 9:15 ` [PATCH 1/2] serial: stm32: reset dma buffers during probe Erwan Le Ray
@ 2021-05-27 9:15 ` Erwan Le Ray
1 sibling, 0 replies; 6+ messages in thread
From: Erwan Le Ray @ 2021-05-27 9:15 UTC (permalink / raw)
To: Greg Kroah-Hartman, Jiri Slaby, Maxime Coquelin, Alexandre Torgue
Cc: linux-serial, linux-stm32, linux-arm-kernel, linux-kernel,
Erwan Le Ray, Fabrice Gasnier, Valentin Caron, Amelie Delaunay,
Etienne Carriere
Defer device probe operation when a DMA channel request probe deferral.
With this change both DMA channels are acquired before DMA channels are
configured. Once no probe deferral is expected, DMAs are
configured and any failure in their configuration will make the driver
to fallback to interrupt mode as prior this change.
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Signed-off-by: Etienne Carriere <etienne.carriere@foss.st.com>
diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index 2ac3b30477a7..7fa54ec11a84 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -1184,6 +1184,14 @@ static const struct of_device_id stm32_match[] = {
MODULE_DEVICE_TABLE(of, stm32_match);
#endif
+static void stm32_usart_of_dma_rx_remove(struct stm32_port *stm32port,
+ struct platform_device *pdev)
+{
+ if (stm32port->rx_buf)
+ dma_free_coherent(&pdev->dev, RX_BUF_L, stm32port->rx_buf,
+ stm32port->rx_dma_buf);
+}
+
static int stm32_usart_of_dma_rx_probe(struct stm32_port *stm32port,
struct platform_device *pdev)
{
@@ -1201,19 +1209,11 @@ static int stm32_usart_of_dma_rx_probe(struct stm32_port *stm32port,
if (uart_console(port))
return -ENODEV;
- /* Request DMA RX channel */
- stm32port->rx_ch = dma_request_slave_channel(dev, "rx");
- if (!stm32port->rx_ch) {
- dev_info(dev, "rx dma alloc failed\n");
- return -ENODEV;
- }
stm32port->rx_buf = dma_alloc_coherent(&pdev->dev, RX_BUF_L,
&stm32port->rx_dma_buf,
GFP_KERNEL);
- if (!stm32port->rx_buf) {
- ret = -ENOMEM;
- goto alloc_err;
- }
+ if (!stm32port->rx_buf)
+ return -ENOMEM;
/* Configure DMA channel */
memset(&config, 0, sizeof(config));
@@ -1223,8 +1223,8 @@ static int stm32_usart_of_dma_rx_probe(struct stm32_port *stm32port,
ret = dmaengine_slave_config(stm32port->rx_ch, &config);
if (ret < 0) {
dev_err(dev, "rx dma channel config failed\n");
- ret = -ENODEV;
- goto config_err;
+ stm32_usart_of_dma_rx_remove(stm32port, pdev);
+ return ret;
}
/* Prepare a DMA cyclic transaction */
@@ -1234,8 +1234,8 @@ static int stm32_usart_of_dma_rx_probe(struct stm32_port *stm32port,
DMA_PREP_INTERRUPT);
if (!desc) {
dev_err(dev, "rx dma prep cyclic failed\n");
- ret = -ENODEV;
- goto config_err;
+ stm32_usart_of_dma_rx_remove(stm32port, pdev);
+ return -ENODEV;
}
/* No callback as dma buffer is drained on usart interrupt */
@@ -1246,24 +1246,22 @@ static int stm32_usart_of_dma_rx_probe(struct stm32_port *stm32port,
ret = dma_submit_error(dmaengine_submit(desc));
if (ret) {
dmaengine_terminate_sync(stm32port->rx_ch);
- goto config_err;
+ stm32_usart_of_dma_rx_remove(stm32port, pdev);
+ return ret;
}
/* Issue pending DMA requests */
dma_async_issue_pending(stm32port->rx_ch);
return 0;
+}
-config_err:
- dma_free_coherent(&pdev->dev,
- RX_BUF_L, stm32port->rx_buf,
- stm32port->rx_dma_buf);
-
-alloc_err:
- dma_release_channel(stm32port->rx_ch);
- stm32port->rx_ch = NULL;
-
- return ret;
+static void stm32_usart_of_dma_tx_remove(struct stm32_port *stm32port,
+ struct platform_device *pdev)
+{
+ if (stm32port->tx_buf)
+ dma_free_coherent(&pdev->dev, TX_BUF_L, stm32port->tx_buf,
+ stm32port->tx_dma_buf);
}
static int stm32_usart_of_dma_tx_probe(struct stm32_port *stm32port,
@@ -1277,19 +1275,11 @@ static int stm32_usart_of_dma_tx_probe(struct stm32_port *stm32port,
stm32port->tx_dma_busy = false;
- /* Request DMA TX channel */
- stm32port->tx_ch = dma_request_slave_channel(dev, "tx");
- if (!stm32port->tx_ch) {
- dev_info(dev, "tx dma alloc failed\n");
- return -ENODEV;
- }
stm32port->tx_buf = dma_alloc_coherent(&pdev->dev, TX_BUF_L,
&stm32port->tx_dma_buf,
GFP_KERNEL);
- if (!stm32port->tx_buf) {
- ret = -ENOMEM;
- goto alloc_err;
- }
+ if (!stm32port->tx_buf)
+ return -ENOMEM;
/* Configure DMA channel */
memset(&config, 0, sizeof(config));
@@ -1299,22 +1289,11 @@ static int stm32_usart_of_dma_tx_probe(struct stm32_port *stm32port,
ret = dmaengine_slave_config(stm32port->tx_ch, &config);
if (ret < 0) {
dev_err(dev, "tx dma channel config failed\n");
- ret = -ENODEV;
- goto config_err;
+ stm32_usart_of_dma_tx_remove(stm32port, pdev);
+ return ret;
}
return 0;
-
-config_err:
- dma_free_coherent(&pdev->dev,
- TX_BUF_L, stm32port->tx_buf,
- stm32port->tx_dma_buf);
-
-alloc_err:
- dma_release_channel(stm32port->tx_ch);
- stm32port->tx_ch = NULL;
-
- return ret;
}
static int stm32_usart_serial_probe(struct platform_device *pdev)
@@ -1338,16 +1317,43 @@ static int stm32_usart_serial_probe(struct platform_device *pdev)
device_set_wakeup_capable(&pdev->dev, true);
ret = dev_pm_set_wake_irq(&pdev->dev, stm32port->port.irq);
if (ret)
- goto err_nowup;
+ goto err_deinit_port;
}
- ret = stm32_usart_of_dma_rx_probe(stm32port, pdev);
- if (ret)
- dev_info(&pdev->dev, "interrupt mode used for rx (no dma)\n");
+ stm32port->rx_ch = dma_request_chan(&pdev->dev, "rx");
+ if (PTR_ERR(stm32port->rx_ch) == -EPROBE_DEFER) {
+ ret = -EPROBE_DEFER;
+ goto err_wakeirq;
+ }
+ /* Fall back in interrupt mode for any non-deferral error */
+ if (IS_ERR(stm32port->rx_ch))
+ stm32port->rx_ch = NULL;
+
+ stm32port->tx_ch = dma_request_chan(&pdev->dev, "tx");
+ if (PTR_ERR(stm32port->tx_ch) == -EPROBE_DEFER) {
+ ret = -EPROBE_DEFER;
+ goto err_dma_rx;
+ }
+ /* Fall back in interrupt mode for any non-deferral error */
+ if (IS_ERR(stm32port->tx_ch))
+ stm32port->tx_ch = NULL;
- ret = stm32_usart_of_dma_tx_probe(stm32port, pdev);
- if (ret)
- dev_info(&pdev->dev, "interrupt mode used for tx (no dma)\n");
+ if (stm32port->rx_ch && stm32_usart_of_dma_rx_probe(stm32port, pdev)) {
+ /* Fall back in interrupt mode */
+ dma_release_channel(stm32port->rx_ch);
+ stm32port->rx_ch = NULL;
+ }
+
+ if (stm32port->tx_ch && stm32_usart_of_dma_tx_probe(stm32port, pdev)) {
+ /* Fall back in interrupt mode */
+ dma_release_channel(stm32port->tx_ch);
+ stm32port->tx_ch = NULL;
+ }
+
+ if (!stm32port->rx_ch)
+ dev_info(&pdev->dev, "interrupt mode for rx (no dma)\n");
+ if (!stm32port->tx_ch)
+ dev_info(&pdev->dev, "interrupt mode for tx (no dma)\n");
platform_set_drvdata(pdev, &stm32port->port);
@@ -1368,30 +1374,23 @@ static int stm32_usart_serial_probe(struct platform_device *pdev)
pm_runtime_set_suspended(&pdev->dev);
pm_runtime_put_noidle(&pdev->dev);
- if (stm32port->rx_ch) {
- dmaengine_terminate_async(stm32port->rx_ch);
- dma_release_channel(stm32port->rx_ch);
- }
-
- if (stm32port->rx_dma_buf)
- dma_free_coherent(&pdev->dev,
- RX_BUF_L, stm32port->rx_buf,
- stm32port->rx_dma_buf);
-
if (stm32port->tx_ch) {
- dmaengine_terminate_async(stm32port->tx_ch);
+ stm32_usart_of_dma_tx_remove(stm32port, pdev);
dma_release_channel(stm32port->tx_ch);
}
- if (stm32port->tx_dma_buf)
- dma_free_coherent(&pdev->dev,
- TX_BUF_L, stm32port->tx_buf,
- stm32port->tx_dma_buf);
+ if (stm32port->rx_ch)
+ stm32_usart_of_dma_rx_remove(stm32port, pdev);
+err_dma_rx:
+ if (stm32port->rx_ch)
+ dma_release_channel(stm32port->rx_ch);
+
+err_wakeirq:
if (stm32port->wakeup_src)
dev_pm_clear_wake_irq(&pdev->dev);
-err_nowup:
+err_deinit_port:
if (stm32port->wakeup_src)
device_set_wakeup_capable(&pdev->dev, false);
@@ -1418,28 +1417,20 @@ static int stm32_usart_serial_remove(struct platform_device *pdev)
stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAR);
+ if (stm32_port->tx_ch) {
+ dmaengine_terminate_async(stm32_port->tx_ch);
+ stm32_usart_of_dma_tx_remove(stm32_port, pdev);
+ dma_release_channel(stm32_port->tx_ch);
+ }
+
if (stm32_port->rx_ch) {
dmaengine_terminate_async(stm32_port->rx_ch);
+ stm32_usart_of_dma_rx_remove(stm32_port, pdev);
dma_release_channel(stm32_port->rx_ch);
}
- if (stm32_port->rx_dma_buf)
- dma_free_coherent(&pdev->dev,
- RX_BUF_L, stm32_port->rx_buf,
- stm32_port->rx_dma_buf);
-
stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
- if (stm32_port->tx_ch) {
- dmaengine_terminate_async(stm32_port->tx_ch);
- dma_release_channel(stm32_port->tx_ch);
- }
-
- if (stm32_port->tx_dma_buf)
- dma_free_coherent(&pdev->dev,
- TX_BUF_L, stm32_port->tx_buf,
- stm32_port->tx_dma_buf);
-
if (stm32_port->wakeup_src) {
dev_pm_clear_wake_irq(&pdev->dev);
device_init_wakeup(&pdev->dev, false);
--
2.17.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH 1/2] serial: stm32: reset dma buffers during probe
2021-05-27 9:15 ` [PATCH 1/2] serial: stm32: reset dma buffers during probe Erwan Le Ray
@ 2021-05-27 9:49 ` Greg Kroah-Hartman
2021-06-09 12:38 ` Greg Kroah-Hartman
2021-06-10 8:54 ` Erwan LE RAY
0 siblings, 2 replies; 6+ messages in thread
From: Greg Kroah-Hartman @ 2021-05-27 9:49 UTC (permalink / raw)
To: Erwan Le Ray
Cc: Jiri Slaby, Maxime Coquelin, Alexandre Torgue, linux-serial,
linux-stm32, linux-arm-kernel, linux-kernel, Fabrice Gasnier,
Valentin Caron, Amelie Delaunay
On Thu, May 27, 2021 at 11:15:36AM +0200, Erwan Le Ray wrote:
> Reset Rx and Tx dma buffers during probe to avoid freeing
> invalid buffer in no dma mode.
>
> Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
>
> diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
> index c2ae7b392b86..2ac3b30477a7 100644
> --- a/drivers/tty/serial/stm32-usart.c
> +++ b/drivers/tty/serial/stm32-usart.c
> @@ -1168,6 +1168,8 @@ static struct stm32_port *stm32_usart_of_get_port(struct platform_device *pdev)
> stm32_ports[id].cr1_irq = USART_CR1_RXNEIE;
> stm32_ports[id].cr3_irq = 0;
> stm32_ports[id].last_res = RX_BUF_L;
> + stm32_ports[id].rx_dma_buf = 0;
> + stm32_ports[id].tx_dma_buf = 0;
> return &stm32_ports[id];
> }
>
> --
> 2.17.1
>
Is this a bugfix? if so, what commit does this fix and does it need to
be backported anywhere?
thanks,
greg k-h
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 1/2] serial: stm32: reset dma buffers during probe
2021-05-27 9:49 ` Greg Kroah-Hartman
@ 2021-06-09 12:38 ` Greg Kroah-Hartman
2021-06-10 8:54 ` Erwan LE RAY
1 sibling, 0 replies; 6+ messages in thread
From: Greg Kroah-Hartman @ 2021-06-09 12:38 UTC (permalink / raw)
To: Erwan Le Ray
Cc: Jiri Slaby, Maxime Coquelin, Alexandre Torgue, linux-serial,
linux-stm32, linux-arm-kernel, linux-kernel, Fabrice Gasnier,
Valentin Caron, Amelie Delaunay
On Thu, May 27, 2021 at 11:49:01AM +0200, Greg Kroah-Hartman wrote:
> On Thu, May 27, 2021 at 11:15:36AM +0200, Erwan Le Ray wrote:
> > Reset Rx and Tx dma buffers during probe to avoid freeing
> > invalid buffer in no dma mode.
> >
> > Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
> >
> > diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
> > index c2ae7b392b86..2ac3b30477a7 100644
> > --- a/drivers/tty/serial/stm32-usart.c
> > +++ b/drivers/tty/serial/stm32-usart.c
> > @@ -1168,6 +1168,8 @@ static struct stm32_port *stm32_usart_of_get_port(struct platform_device *pdev)
> > stm32_ports[id].cr1_irq = USART_CR1_RXNEIE;
> > stm32_ports[id].cr3_irq = 0;
> > stm32_ports[id].last_res = RX_BUF_L;
> > + stm32_ports[id].rx_dma_buf = 0;
> > + stm32_ports[id].tx_dma_buf = 0;
> > return &stm32_ports[id];
> > }
> >
> > --
> > 2.17.1
> >
>
> Is this a bugfix? if so, what commit does this fix and does it need to
> be backported anywhere?
Due to lack of a response, I've dropped this from my queue. Please add
the needed information to the patch when you get the chance to resend
this.
thanks,
greg k-h
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 1/2] serial: stm32: reset dma buffers during probe
2021-05-27 9:49 ` Greg Kroah-Hartman
2021-06-09 12:38 ` Greg Kroah-Hartman
@ 2021-06-10 8:54 ` Erwan LE RAY
1 sibling, 0 replies; 6+ messages in thread
From: Erwan LE RAY @ 2021-06-10 8:54 UTC (permalink / raw)
To: Greg Kroah-Hartman
Cc: Jiri Slaby, Maxime Coquelin, Alexandre Torgue, linux-serial,
linux-stm32, linux-arm-kernel, linux-kernel, Fabrice Gasnier,
Valentin Caron, Amelie Delaunay
Hi Greg,
Thanks for your question. This old patch is finally not necessary any more.
You can cancel this series, I will resend the second patch.
Best regards, Erwan.
On 5/27/21 11:49 AM, Greg Kroah-Hartman wrote:
> On Thu, May 27, 2021 at 11:15:36AM +0200, Erwan Le Ray wrote:
>> Reset Rx and Tx dma buffers during probe to avoid freeing
>> invalid buffer in no dma mode.
>>
>> Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
>>
>> diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
>> index c2ae7b392b86..2ac3b30477a7 100644
>> --- a/drivers/tty/serial/stm32-usart.c
>> +++ b/drivers/tty/serial/stm32-usart.c
>> @@ -1168,6 +1168,8 @@ static struct stm32_port *stm32_usart_of_get_port(struct platform_device *pdev)
>> stm32_ports[id].cr1_irq = USART_CR1_RXNEIE;
>> stm32_ports[id].cr3_irq = 0;
>> stm32_ports[id].last_res = RX_BUF_L;
>> + stm32_ports[id].rx_dma_buf = 0;
>> + stm32_ports[id].tx_dma_buf = 0;
>> return &stm32_ports[id];
>> }
>>
>> --
>> 2.17.1
>>
>
> Is this a bugfix? if so, what commit does this fix and does it need to
> be backported anywhere?
>
> thanks,
>
> greg k-h
>
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2021-06-10 8:54 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-05-27 9:15 [PATCH 0/2] stm32 usart improve DMA probe Erwan Le Ray
2021-05-27 9:15 ` [PATCH 1/2] serial: stm32: reset dma buffers during probe Erwan Le Ray
2021-05-27 9:49 ` Greg Kroah-Hartman
2021-06-09 12:38 ` Greg Kroah-Hartman
2021-06-10 8:54 ` Erwan LE RAY
2021-05-27 9:15 ` [PATCH 2/2] serial: stm32: defer probe for dma devices Erwan Le Ray
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