This driver is checking the access rights of the different
peripherals connected to the system bus. If access is denied,
the associated device tree node is skipped so the platform bus
does not probe it.
Signed-off-by: Loic PALLARDY <[email protected]>
Signed-off-by: Gatien Chevallier <[email protected]>
---
MAINTAINERS | 6 ++
drivers/bus/Kconfig | 9 ++
drivers/bus/Makefile | 1 +
drivers/bus/stm32_sys_bus.c | 180 ++++++++++++++++++++++++++++++++++++
4 files changed, 196 insertions(+)
create mode 100644 drivers/bus/stm32_sys_bus.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 886d3f69ee64..768a8272233e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -19522,6 +19522,12 @@ L: [email protected]
S: Maintained
F: drivers/spi/spi-stm32.c
+ST STM32 SYS BUS DRIVER
+M: Gatien Chevallier <[email protected]>
+S: Maintained
+F: Documentation/devicetree/bindings/bus/st,sys-bus.yaml
+F: drivers/bus/stm32_sys_bus.c
+
ST STPDDC60 DRIVER
M: Daniel Nilsson <[email protected]>
L: [email protected]
diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig
index 7bfe998f3514..638bf5839cb0 100644
--- a/drivers/bus/Kconfig
+++ b/drivers/bus/Kconfig
@@ -163,6 +163,15 @@ config QCOM_SSC_BLOCK_BUS
i2c/spi/uart controllers, a hexagon core, and a clock controller
which provides clocks for the above.
+config STM32_SYS_BUS
+ bool "STM32 System bus controller"
+ depends on ARCH_STM32
+ default MACH_STM32MP157 || MACH_STM32MP13
+ help
+ Say y to enable device access right verification before device probing.
+ If access not granted, device won't be probed and an error message will
+ provide the reason.
+
config SUN50I_DE2_BUS
bool "Allwinner A64 DE2 Bus Driver"
default ARM64
diff --git a/drivers/bus/Makefile b/drivers/bus/Makefile
index d90eed189a65..b15fdc42d0be 100644
--- a/drivers/bus/Makefile
+++ b/drivers/bus/Makefile
@@ -26,6 +26,7 @@ obj-$(CONFIG_OMAP_INTERCONNECT) += omap_l3_smx.o omap_l3_noc.o
obj-$(CONFIG_OMAP_OCP2SCP) += omap-ocp2scp.o
obj-$(CONFIG_QCOM_EBI2) += qcom-ebi2.o
obj-$(CONFIG_QCOM_SSC_BLOCK_BUS) += qcom-ssc-block-bus.o
+obj-$(CONFIG_STM32_SYS_BUS) += stm32_sys_bus.o
obj-$(CONFIG_SUN50I_DE2_BUS) += sun50i-de2.o
obj-$(CONFIG_SUNXI_RSB) += sunxi-rsb.o
obj-$(CONFIG_OF) += simple-pm-bus.o
diff --git a/drivers/bus/stm32_sys_bus.c b/drivers/bus/stm32_sys_bus.c
new file mode 100644
index 000000000000..e4c21e24b65e
--- /dev/null
+++ b/drivers/bus/stm32_sys_bus.c
@@ -0,0 +1,180 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2022, STMicroelectronics - All Rights Reserved
+ */
+
+#include <linux/bitfield.h>
+#include <linux/bits.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+
+/* ETZPC peripheral as firewall bus */
+/* ETZPC registers */
+#define ETZPC_DECPROT 0x10
+
+/* ETZPC miscellaneous */
+#define ETZPC_PROT_MASK GENMASK(1, 0)
+#define ETZPC_PROT_A7NS 0x3
+#define ETZPC_DECPROT_SHIFT 1
+
+#define IDS_PER_DECPROT_REGS 16
+#define STM32MP15_ETZPC_ENTRIES 96
+#define STM32MP13_ETZPC_ENTRIES 64
+
+struct sys_bus_data;
+
+struct stm32_sys_bus_match_data {
+ const u32 *map_table;
+ unsigned int max_entries;
+ int (*sys_bus_get_access)(struct sys_bus_data *pdata, struct device_node *np);
+};
+
+struct sys_bus_data {
+ struct stm32_sys_bus_match_data *pconf;
+ void __iomem *sys_bus_base;
+ struct device *dev;
+};
+
+static int stm32_sys_bus_get_periph_id(struct sys_bus_data *pdata, struct device_node *np, u32 *id)
+{
+ int err;
+ u32 feature_domain_cell[2];
+ u32 id_bus;
+
+ /* Get reg from device node */
+ err = of_property_read_u32_array(np, "feature-domains", feature_domain_cell, 2);
+ if (err) {
+ dev_err(pdata->dev, "Unable to find feature-domains property\n");
+ return -ENODEV;
+ }
+
+ id_bus = feature_domain_cell[1];
+
+ if (id_bus >= pdata->pconf->max_entries) {
+ dev_err(pdata->dev, "Invalid sys bus ID for %s\n", np->full_name);
+ return -EINVAL;
+ }
+
+ *id = id_bus;
+
+ return 0;
+}
+
+static int stm32_etzpc_get_access(struct sys_bus_data *pdata, struct device_node *np)
+{
+ int err;
+ u32 offset, reg_offset, sec_val, id;
+
+ err = stm32_sys_bus_get_periph_id(pdata, np, &id);
+ if (err)
+ return err;
+
+ /* Check access configuration, 16 peripherals per register */
+ reg_offset = ETZPC_DECPROT + 0x4 * (id / IDS_PER_DECPROT_REGS);
+ offset = (id % IDS_PER_DECPROT_REGS) << ETZPC_DECPROT_SHIFT;
+
+ /* Verify peripheral is non-secure and attributed to cortex A7 */
+ sec_val = (readl(pdata->sys_bus_base + reg_offset) >> offset) & ETZPC_PROT_MASK;
+ if (sec_val != ETZPC_PROT_A7NS) {
+ dev_dbg(pdata->dev, "Invalid bus configuration: reg_offset %#x, value %d\n",
+ reg_offset, sec_val);
+ return -EACCES;
+ }
+
+ return 0;
+}
+
+static void stm32_sys_bus_populate(struct sys_bus_data *pdata)
+{
+ struct device *parent;
+ struct device_node *child;
+
+ parent = pdata->dev;
+
+ dev_dbg(parent, "Populating %s system bus\n", pdata->dev->driver->name);
+
+ for_each_available_child_of_node(dev_of_node(parent), child) {
+ if (pdata->pconf->sys_bus_get_access(pdata, child)) {
+ /*
+ * Peripheral access not allowed.
+ * Mark the node as populated so platform bus won't probe it
+ */
+ of_node_set_flag(child, OF_POPULATED);
+ dev_dbg(parent, "%s: Peripheral will not be probed\n",
+ child->full_name);
+ }
+ }
+}
+
+static int stm32_sys_bus_probe(struct platform_device *pdev)
+{
+ struct sys_bus_data *pdata;
+ struct resource *res;
+ void __iomem *mmio;
+ struct stm32_sys_bus_match_data *mdata;
+ struct device_node *np = pdev->dev.of_node;
+
+ pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
+ if (!pdata)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ mmio = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(mmio))
+ return PTR_ERR(mmio);
+
+ pdata->sys_bus_base = mmio;
+
+ mdata = (struct stm32_sys_bus_match_data *)of_device_get_match_data(&pdev->dev);
+ if (!mdata)
+ return -EINVAL;
+
+ pdata->pconf = mdata;
+ pdata->dev = &pdev->dev;
+
+ platform_set_drvdata(pdev, pdata);
+
+ stm32_sys_bus_populate(pdata);
+
+ /* Populate all available nodes */
+ return of_platform_populate(np, NULL, NULL, &pdev->dev);
+}
+
+static const struct stm32_sys_bus_match_data stm32mp15_sys_bus_data = {
+ .max_entries = STM32MP15_ETZPC_ENTRIES,
+ .sys_bus_get_access = stm32_etzpc_get_access,
+};
+
+static const struct stm32_sys_bus_match_data stm32mp13_sys_bus_data = {
+ .max_entries = STM32MP13_ETZPC_ENTRIES,
+ .sys_bus_get_access = stm32_etzpc_get_access,
+};
+
+static const struct of_device_id stm32_sys_bus_of_match[] = {
+ { .compatible = "st,stm32mp15-sys-bus", .data = &stm32mp15_sys_bus_data },
+ { .compatible = "st,stm32mp13-sys-bus", .data = &stm32mp13_sys_bus_data },
+ {}
+};
+MODULE_DEVICE_TABLE(of, stm32_sys_bus_of_match);
+
+static struct platform_driver stm32_sys_bus_driver = {
+ .probe = stm32_sys_bus_probe,
+ .driver = {
+ .name = "stm32-sys-bus",
+ .of_match_table = stm32_sys_bus_of_match,
+ },
+};
+
+static int __init stm32_sys_bus_init(void)
+{
+ return platform_driver_register(&stm32_sys_bus_driver);
+}
+arch_initcall(stm32_sys_bus_init);
+
--
2.25.1
On 21/12/2022 18:30, Gatien Chevallier wrote:
> This driver is checking the access rights of the different
> peripherals connected to the system bus. If access is denied,
> the associated device tree node is skipped so the platform bus
> does not probe it.
>
> Signed-off-by: Loic PALLARDY <[email protected]>
> Signed-off-by: Gatien Chevallier <[email protected]>
> ---
> MAINTAINERS | 6 ++
> drivers/bus/Kconfig | 9 ++
> drivers/bus/Makefile | 1 +
> drivers/bus/stm32_sys_bus.c | 180 ++++++++++++++++++++++++++++++++++++
> 4 files changed, 196 insertions(+)
> create mode 100644 drivers/bus/stm32_sys_bus.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 886d3f69ee64..768a8272233e 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -19522,6 +19522,12 @@ L: [email protected]
> S: Maintained
> F: drivers/spi/spi-stm32.c
>
> +ST STM32 SYS BUS DRIVER
> +M: Gatien Chevallier <[email protected]>
> +S: Maintained
> +F: Documentation/devicetree/bindings/bus/st,sys-bus.yaml
> +F: drivers/bus/stm32_sys_bus.c
> +
> ST STPDDC60 DRIVER
> M: Daniel Nilsson <[email protected]>
> L: [email protected]
> diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig
> index 7bfe998f3514..638bf5839cb0 100644
> --- a/drivers/bus/Kconfig
> +++ b/drivers/bus/Kconfig
> @@ -163,6 +163,15 @@ config QCOM_SSC_BLOCK_BUS
> i2c/spi/uart controllers, a hexagon core, and a clock controller
> which provides clocks for the above.
>
> +config STM32_SYS_BUS
> + bool "STM32 System bus controller"
> + depends on ARCH_STM32
|| COMPILE_TEST
> + default MACH_STM32MP157 || MACH_STM32MP13
> + help
> + Say y to enable device access right verification before device probing.
> + If access not granted, device won't be probed and an error message will
> + provide the reason.
(...)
> +
> +static int stm32_sys_bus_probe(struct platform_device *pdev)
> +{
> + struct sys_bus_data *pdata;
> + struct resource *res;
> + void __iomem *mmio;
> + struct stm32_sys_bus_match_data *mdata;
> + struct device_node *np = pdev->dev.of_node;
> +
> + pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
> + if (!pdata)
> + return -ENOMEM;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + mmio = devm_ioremap_resource(&pdev->dev, res);
Use helper for these two.
> + if (IS_ERR(mmio))
> + return PTR_ERR(mmio);
> +
> + pdata->sys_bus_base = mmio;
> +
> + mdata = (struct stm32_sys_bus_match_data *)of_device_get_match_data(&pdev->dev);
Why do you need the cast?
> + if (!mdata)
Can you explain the case when this can actually happen? If it can, you
have bug in ID table.
> + return -EINVAL;
> +
> + pdata->pconf = mdata;
> + pdata->dev = &pdev->dev;
> +
> + platform_set_drvdata(pdev, pdata);
> +
> + stm32_sys_bus_populate(pdata);
> +
> + /* Populate all available nodes */
> + return of_platform_populate(np, NULL, NULL, &pdev->dev);
> +}
> +
> +static const struct stm32_sys_bus_match_data stm32mp15_sys_bus_data = {
> + .max_entries = STM32MP15_ETZPC_ENTRIES,
> + .sys_bus_get_access = stm32_etzpc_get_access,
> +};
> +
> +static const struct stm32_sys_bus_match_data stm32mp13_sys_bus_data = {
> + .max_entries = STM32MP13_ETZPC_ENTRIES,
> + .sys_bus_get_access = stm32_etzpc_get_access,
It's the same as previous, drop.
> +};
> +
> +static const struct of_device_id stm32_sys_bus_of_match[] = {
> + { .compatible = "st,stm32mp15-sys-bus", .data = &stm32mp15_sys_bus_data },
> + { .compatible = "st,stm32mp13-sys-bus", .data = &stm32mp13_sys_bus_data },
> + {}
> +};
> +MODULE_DEVICE_TABLE(of, stm32_sys_bus_of_match);
> +
> +static struct platform_driver stm32_sys_bus_driver = {
> + .probe = stm32_sys_bus_probe,
> + .driver = {
> + .name = "stm32-sys-bus",
> + .of_match_table = stm32_sys_bus_of_match,
> + },
> +};
> +
> +static int __init stm32_sys_bus_init(void)
> +{
> + return platform_driver_register(&stm32_sys_bus_driver);
> +}
> +arch_initcall(stm32_sys_bus_init);
> +
Best regards,
Krzysztof
On 22/12/2022 15:30, Gatien CHEVALLIER wrote:
>>
>>> + if (IS_ERR(mmio))
>>> + return PTR_ERR(mmio);
>>> +
>>> + pdata->sys_bus_base = mmio;
>>> +
>>> + mdata = (struct stm32_sys_bus_match_data *)of_device_get_match_data(&pdev->dev);
>>
>> Why do you need the cast?
>
> I do not :) TBH, mdata is not useful at all. Changing to directly assign
> to pdata->pconf, that is now const there is no reason to modify it.
mdata should be const and then no need for cast.
>
>>
>>> + if (!mdata)
>>
>> Can you explain the case when this can actually happen? If it can, you
>> have bug in ID table.
>
> No I cannot as the driver is probed. It is only a sanity check, I can
> remove it for V3. However the function can return NULL... Would you
> prefer an explicit check on NULL or a simple removal?
I propose to drop it. This simply cannot happen.
>
>>
>>> + return -EINVAL;
>>> +
Best regards,
Krzysztof
On 12/22/22 11:28, Krzysztof Kozlowski wrote:
> On 21/12/2022 18:30, Gatien Chevallier wrote:
>> This driver is checking the access rights of the different
>> peripherals connected to the system bus. If access is denied,
>> the associated device tree node is skipped so the platform bus
>> does not probe it.
>>
>> Signed-off-by: Loic PALLARDY <[email protected]>
>> Signed-off-by: Gatien Chevallier <[email protected]>
>> ---
>> MAINTAINERS | 6 ++
>> drivers/bus/Kconfig | 9 ++
>> drivers/bus/Makefile | 1 +
>> drivers/bus/stm32_sys_bus.c | 180 ++++++++++++++++++++++++++++++++++++
>> 4 files changed, 196 insertions(+)
>> create mode 100644 drivers/bus/stm32_sys_bus.c
>>
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index 886d3f69ee64..768a8272233e 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -19522,6 +19522,12 @@ L: [email protected]
>> S: Maintained
>> F: drivers/spi/spi-stm32.c
>>
>> +ST STM32 SYS BUS DRIVER
>> +M: Gatien Chevallier <[email protected]>
>> +S: Maintained
>> +F: Documentation/devicetree/bindings/bus/st,sys-bus.yaml
>> +F: drivers/bus/stm32_sys_bus.c
>> +
>> ST STPDDC60 DRIVER
>> M: Daniel Nilsson <[email protected]>
>> L: [email protected]
>> diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig
>> index 7bfe998f3514..638bf5839cb0 100644
>> --- a/drivers/bus/Kconfig
>> +++ b/drivers/bus/Kconfig
>> @@ -163,6 +163,15 @@ config QCOM_SSC_BLOCK_BUS
>> i2c/spi/uart controllers, a hexagon core, and a clock controller
>> which provides clocks for the above.
>>
>> +config STM32_SYS_BUS
>> + bool "STM32 System bus controller"
>> + depends on ARCH_STM32
>
> || COMPILE_TEST
Sure, I will add this in V3
>
>> + default MACH_STM32MP157 || MACH_STM32MP13
>> + help
>> + Say y to enable device access right verification before device probing.
>> + If access not granted, device won't be probed and an error message will
>> + provide the reason.
>
> (...)
>
>> +
>> +static int stm32_sys_bus_probe(struct platform_device *pdev)
>> +{
>> + struct sys_bus_data *pdata;
>> + struct resource *res;
>> + void __iomem *mmio;
>> + struct stm32_sys_bus_match_data *mdata;
>> + struct device_node *np = pdev->dev.of_node;
>> +
>> + pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
>> + if (!pdata)
>> + return -ENOMEM;
>> +
>> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> + mmio = devm_ioremap_resource(&pdev->dev, res);
>
> Use helper for these two.
Ok, I will use devm_platform_ioremap_resource()
>
>> + if (IS_ERR(mmio))
>> + return PTR_ERR(mmio);
>> +
>> + pdata->sys_bus_base = mmio;
>> +
>> + mdata = (struct stm32_sys_bus_match_data *)of_device_get_match_data(&pdev->dev);
>
> Why do you need the cast?
I do not :) TBH, mdata is not useful at all. Changing to directly assign
to pdata->pconf, that is now const there is no reason to modify it.
>
>> + if (!mdata)
>
> Can you explain the case when this can actually happen? If it can, you
> have bug in ID table.
No I cannot as the driver is probed. It is only a sanity check, I can
remove it for V3. However the function can return NULL... Would you
prefer an explicit check on NULL or a simple removal?
>
>> + return -EINVAL;
>> +
>> + pdata->pconf = mdata;
>> + pdata->dev = &pdev->dev;
>> +
>> + platform_set_drvdata(pdev, pdata);
>> +
>> + stm32_sys_bus_populate(pdata);
>> +
>> + /* Populate all available nodes */
>> + return of_platform_populate(np, NULL, NULL, &pdev->dev);
>> +}
>> +
>> +static const struct stm32_sys_bus_match_data stm32mp15_sys_bus_data = {
>> + .max_entries = STM32MP15_ETZPC_ENTRIES,
>> + .sys_bus_get_access = stm32_etzpc_get_access,
>> +};
>> +
>> +static const struct stm32_sys_bus_match_data stm32mp13_sys_bus_data = {
>> + .max_entries = STM32MP13_ETZPC_ENTRIES,
>> + .sys_bus_get_access = stm32_etzpc_get_access,
>
> It's the same as previous, drop.
Yes, ops is useless, I will directly call stm32_etzpc_get_access() in V3.
>
>> +};
>> +
>> +static const struct of_device_id stm32_sys_bus_of_match[] = {
>> + { .compatible = "st,stm32mp15-sys-bus", .data = &stm32mp15_sys_bus_data },
>> + { .compatible = "st,stm32mp13-sys-bus", .data = &stm32mp13_sys_bus_data },
>> + {}
>> +};
>> +MODULE_DEVICE_TABLE(of, stm32_sys_bus_of_match);
>> +
>> +static struct platform_driver stm32_sys_bus_driver = {
>> + .probe = stm32_sys_bus_probe,
>> + .driver = {
>> + .name = "stm32-sys-bus",
>> + .of_match_table = stm32_sys_bus_of_match,
>> + },
>> +};
>> +
>> +static int __init stm32_sys_bus_init(void)
>> +{
>> + return platform_driver_register(&stm32_sys_bus_driver);
>> +}
>> +arch_initcall(stm32_sys_bus_init);
>> +
>
> Best regards,
> Krzysztof
>
Best regards,
Gatien