Re: [PATCH 06/13] perf: stm32: introduce DDRPERFM driver
From: Clement LE GOFFIC
Date: Wed Jul 02 2025 - 10:16:27 EST
Hi Philip
On 6/30/25 10:38, Philipp Zabel wrote:
On Mo, 2025-06-23 at 11:27 +0200, Clément Le Goffic wrote:
Introduce the driver for the DDR Performance Monitor available on
STM32MPU SoC.
On STM32MP2 platforms, the DDRPERFM allows to monitor up to 8 DDR events
that come from the DDR Controller such as read or write events.
On STM32MP1 platforms, the DDRPERFM cannot monitor any event on any
counter, there is a notion of set of events.
Events from different sets cannot be monitored at the same time.
The first chosen event selects the set.
The set is coded in the first two bytes of the config value which is on 4
bytes.
On STM32MP25x series, the DDRPERFM clock is shared with the DDR controller
and may be secured by bootloaders.
Access controllers allow to check access to a resource. Use the access
controller defined in the devicetree to know about the access to the
DDRPERFM clock.
Signed-off-by: Clément Le Goffic <clement.legoffic@xxxxxxxxxxx>
---
drivers/perf/Kconfig | 11 +
drivers/perf/Makefile | 1 +
drivers/perf/stm32_ddr_pmu.c | 893 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 905 insertions(+)
[...]
diff --git a/drivers/perf/stm32_ddr_pmu.c b/drivers/perf/stm32_ddr_pmu.c
new file mode 100644
index 000000000000..c0bce1f446a0
--- /dev/null
+++ b/drivers/perf/stm32_ddr_pmu.c
@@ -0,0 +1,893 @@
[...]
+ if (of_property_present(pdev->dev.of_node, "resets")) {
+ rst = devm_reset_control_get(&pdev->dev, NULL);
Use devm_reset_control_get_optional_exclusive() instead. It returns
NULL if the device tree doesn't contain a resets property.
Ok I will have a look, thank you
+ if (IS_ERR(rst)) {
+ dev_err(&pdev->dev, "Failed to get reset\n");
Please consider using dev_err_probe() instead.
Ok
+ ret = PTR_ERR(rst);
+ goto err_clk;
+ }
+ reset_control_assert(rst);
+ reset_control_deassert(rst);
These can be done unconditionally, as they are no-ops for rst == NULL.
Indeed
Best regards,
Clément