Hi Christophe,
Thanks for the review.
On 5/4/24 16:27, Christophe JAILLET wrote:
Le 23/04/2024 à 14:32, Amelie Delaunay a écrit :
STM32 DMA3 driver supports the 3 hardware configurations of the STM32
DMA3
controller:
- LPDMA (Low Power): 4 channels, no FIFO
- GPDMA (General Purpose): 16 channels, FIFO from 8 to 32 bytes
- HPDMA (High Performance): 16 channels, FIFO from 8 to 256 bytes
Hardware configuration of the channels is retrieved from the hardware
configuration registers.
The client can specify its channel requirements through device tree.
STM32 DMA3 channels can be individually reserved either because they are
secure, or dedicated to another CPU.
Indeed, channels availability depends on Resource Isolation Framework
(RIF) configuration. RIF grants access to buses with Compartiment ID
(CIF) filtering, secure and privilege level. It also assigns DMA channels
to one or several processors.
DMA channels used by Linux should be CID-filtered and statically assigned
to CID1 or shared with other CPUs but using semaphore. In case CID
filtering is not configured, dma-channel-mask property can be used to
specify available DMA channels to the kernel, otherwise such channels
will be marked as reserved and can't be used by Linux.
Signed-off-by: Amelie Delaunay
<amelie.delaunay-rj0Iel/JR4NBDgjK7y7TUQ@xxxxxxxxxxxxxxxx>
---
...
+ pm_runtime_set_active(&pdev->dev);
+ pm_runtime_enable(&pdev->dev);
+ pm_runtime_get_noresume(&pdev->dev);
+ pm_runtime_put(&pdev->dev);
+
+ dev_info(&pdev->dev, "STM32 DMA3 registered rev:%lu.%lu\n",
+ FIELD_GET(VERR_MAJREV, verr), FIELD_GET(VERR_MINREV, verr));
+
+ return 0;
+
+err_clk_disable:
+ clk_disable_unprepare(ddata->clk);
+
+ return ret;
+}
+
+static void stm32_dma3_remove(struct platform_device *pdev)
+{
+ pm_runtime_disable(&pdev->dev);
Hi,
missing clk_disable_unprepare(ddata->clk);?
as in the error handling path on the probe just above?
CJ
Clock is entirely managed by pm_runtime, except in error path of probe
since pm_runtime is enabled only at the very end.
Clock is enabled with pm_runtime_resume_and_get() when a channel is
requested or when an asynchronous register access occurs (filter_fn,
debugfs, runtime_resume) and clock is disabled with
pm_runtime_put_sync() when releasing a channel or at the end of
asynchronous register access (filter_fn, debugfs, runtime_suspend).
Adding clk_disable_unprepare(ddata->clk); here leads to clock already
disabled/unprepared warnings in drivers/clk/clk.c
clk_core_disable()/clk_core_unprepare().
+}
...
Regards,
Amelie
