[PATCH 03/13] clk: stm32mp25: add firewall grant_access ops

From: Clément Le Goffic
Date: Mon Jun 23 2025 - 05:31:11 EST


On STM32MP25, the RCC peripheral manages the secure level of resources
that are used by other devices such as clocks.
Declare this peripheral as a firewall controller.

Signed-off-by: Clément Le Goffic <clement.legoffic@xxxxxxxxxxx>
---
drivers/clk/stm32/clk-stm32mp25.c | 40 ++++++++++++++++++++++++++++++++++++++-
1 file changed, 39 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/stm32/clk-stm32mp25.c b/drivers/clk/stm32/clk-stm32mp25.c
index 52f0e8a12926..af4bc06d703a 100644
--- a/drivers/clk/stm32/clk-stm32mp25.c
+++ b/drivers/clk/stm32/clk-stm32mp25.c
@@ -4,8 +4,10 @@
* Author: Gabriel Fernandez <gabriel.fernandez@xxxxxxxxxxx> for STMicroelectronics.
*/

+#include <linux/bus/stm32_firewall.h>
#include <linux/bus/stm32_firewall_device.h>
#include <linux/clk-provider.h>
+#include <linux/device.h>
#include <linux/io.h>
#include <linux/platform_device.h>

@@ -1602,6 +1604,11 @@ static int stm32_rcc_get_access(void __iomem *base, u32 index)
return 0;
}

+static int stm32mp25_rcc_grant_access(struct stm32_firewall_controller *ctrl, u32 firewall_id)
+{
+ return stm32_rcc_get_access(ctrl->mmio, firewall_id);
+}
+
static int stm32mp25_check_security(struct device_node *np, void __iomem *base,
const struct clock_config *cfg)
{
@@ -1970,6 +1977,7 @@ MODULE_DEVICE_TABLE(of, stm32mp25_match_data);

static int stm32mp25_rcc_clocks_probe(struct platform_device *pdev)
{
+ struct stm32_firewall_controller *rcc_controller;
struct device *dev = &pdev->dev;
void __iomem *base;
int ret;
@@ -1982,7 +1990,36 @@ static int stm32mp25_rcc_clocks_probe(struct platform_device *pdev)
if (ret)
return ret;

- return stm32_rcc_init(dev, stm32mp25_match_data, base);
+ ret = stm32_rcc_init(dev, stm32mp25_match_data, base);
+ if (ret)
+ return ret;
+
+ rcc_controller = devm_kzalloc(&pdev->dev, sizeof(*rcc_controller), GFP_KERNEL);
+ if (!rcc_controller)
+ return -ENOMEM;
+
+ rcc_controller->dev = dev;
+ rcc_controller->mmio = base;
+ rcc_controller->name = dev_driver_string(dev);
+ rcc_controller->type = STM32_PERIPHERAL_FIREWALL;
+ rcc_controller->grant_access = stm32mp25_rcc_grant_access;
+
+ platform_set_drvdata(pdev, rcc_controller);
+
+ ret = stm32_firewall_controller_register(rcc_controller);
+ if (ret) {
+ dev_err(dev, "Couldn't register as a firewall controller: %d\n", ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+static void stm32mp25_rcc_clocks_remove(struct platform_device *pdev)
+{
+ struct stm32_firewall_controller *rcc_controller = platform_get_drvdata(pdev);
+
+ stm32_firewall_controller_unregister(rcc_controller);
}

static struct platform_driver stm32mp25_rcc_clocks_driver = {
@@ -1991,6 +2028,7 @@ static struct platform_driver stm32mp25_rcc_clocks_driver = {
.of_match_table = stm32mp25_match_data,
},
.probe = stm32mp25_rcc_clocks_probe,
+ .remove = stm32mp25_rcc_clocks_remove,
};

static int __init stm32mp25_clocks_init(void)

--
2.43.0