[PATCH v2 4/5] bus: stm32: Add stm32 ETZPC firewall bus controller

From: Benjamin Gaignard
Date: Thu Apr 23 2020 - 09:19:50 EST

Add STM32 Extended TrustZone Protection bus controller.
For each of device-tree nodes it will check and apply
firewall configuration. If it doesn't match the device
will not be probed by platform bus.

A device could be configured to be accessible by trusted world,
co-processor or non-secure world.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@xxxxxx>
---
drivers/bus/stm32/Kconfig | 8 ++
drivers/bus/stm32/Makefile | 1 +
drivers/bus/stm32/stm32-etzpc.c | 160 ++++++++++++++++++++++++++++
include/dt-bindings/bus/stm32/stm32-etzpc.h | 90 ++++++++++++++++
4 files changed, 259 insertions(+)
create mode 100644 drivers/bus/stm32/stm32-etzpc.c
create mode 100644 include/dt-bindings/bus/stm32/stm32-etzpc.h

diff --git a/drivers/bus/stm32/Kconfig b/drivers/bus/stm32/Kconfig
index 57221e833e2d..5dc6e2504de5 100644
--- a/drivers/bus/stm32/Kconfig
+++ b/drivers/bus/stm32/Kconfig
@@ -1,3 +1,11 @@
config FIREWALL_CONTROLLERS
bool "Support of bus firewall controllers"
depends on OF
+
+config STM32_ETZPC
+ bool "STM32 ETZPC bus controller"
+ depends on MACH_STM32MP157
+ select FIREWALL_CONTROLLERS
+ help
+ Select y to enable STM32 Extended TrustZone Protection
+ Controller (ETZPC)
diff --git a/drivers/bus/stm32/Makefile b/drivers/bus/stm32/Makefile
index eb6b978d6450..d42e99b5865e 100644
--- a/drivers/bus/stm32/Makefile
+++ b/drivers/bus/stm32/Makefile
@@ -1 +1,2 @@
obj-$(CONFIG_FIREWALL_CONTROLLERS) += firewall.o
+obj-$(CONFIG_STM32_ETZPC) += stm32-etzpc.o
diff --git a/drivers/bus/stm32/stm32-etzpc.c b/drivers/bus/stm32/stm32-etzpc.c
new file mode 100644
index 000000000000..c216c71448ed
--- /dev/null
+++ b/drivers/bus/stm32/stm32-etzpc.c
@@ -0,0 +1,160 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) STMicroelectronics 2020 - All Rights Reserved
+ * Author: Benjamin Gaignard <benjamin.gaignard@xxxxxx> for STMicroelectronics.
+ */
+
+#include <linux/device.h>
+#include <linux/err.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>
+#include <linux/regmap.h>
+
+#include <dt-bindings/bus/stm32/stm32-etzpc.h>
+
+#include "firewall.h"
+
+#define ETZPC_DECPROT 0x010
+#define ETZPC_NUM_LOCKS 94
+
+struct stm32_etzpc {
+ struct regmap_field *fields[ETZPC_NUM_LOCKS];
+};
+
+static int stm32_etzpc_set_config(void *priv, struct of_phandle_args *out_args)
+{
+ struct stm32_etzpc *etzpc = dev_get_drvdata((struct device *)priv);
+ int index = out_args->args[0];
+ unsigned int value = out_args->args[1];
+ u32 status;
+
+ if (out_args->args_count != 2)
+ return -EINVAL;
+
+ if (index >= ETZPC_NUM_LOCKS)
+ return -EINVAL;
+
+ if (value > STM32_ETZPC_NON_SECURE)
+ return -EINVAL;
+
+ regmap_field_force_write(etzpc->fields[index], value);
+
+ /* Hardware could denied the new value, read it back to check it */
+ regmap_field_read(etzpc->fields[index], &status);
+
+ if (value != status) {
+ pr_info("failed to set configuration: index %d, value %d\n",
+ index, value);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static struct firewall_ops stm32_etzpc_ops = {
+ .set_config = stm32_etzpc_set_config,
+};
+
+static const struct regmap_config stm32_etzpc_regmap_cfg = {
+ .reg_bits = 32,
+ .val_bits = 32,
+ .reg_stride = sizeof(u32),
+ .max_register = 0x3FF,
+};
+
+static void stm32_etzpc_populate(struct device *parent)
+{
+ struct device_node *child;
+
+ if (!parent)
+ return;
+
+ for_each_available_child_of_node(dev_of_node(parent), child) {
+ if (firewall_set_default_config(child)) {
+ /*
+ * Failed to set firewall configuration mark the node
+ * as populated so platform bus won't probe it
+ */
+ of_node_set_flag(child, OF_POPULATED);
+ dev_info(parent, "%s: Bad firewall configuration\n",
+ child->name);
+ }
+ }
+}
+
+static int stm32_etzpc_probe(struct platform_device *pdev)
+{
+ struct stm32_etzpc *etzpc;
+ struct regmap *regmap;
+ struct resource *res;
+ void __iomem *mmio;
+ int i, ret;
+
+ etzpc = devm_kzalloc(&pdev->dev, sizeof(*etzpc), GFP_KERNEL);
+ if (!etzpc)
+ 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);
+
+ regmap = devm_regmap_init_mmio(&pdev->dev, mmio,
+ &stm32_etzpc_regmap_cfg);
+
+ for (i = 0; i < ETZPC_NUM_LOCKS; i++) {
+ struct reg_field field;
+
+ /*
+ * Each hardware block status is defined by
+ * a 2 bits field and all of them are packed into
+ * 32 bits registers. Do some computation to get
+ * register offset and the shift.
+ */
+ field.reg = ETZPC_DECPROT + (i >> 4) * sizeof(u32);
+ field.lsb = (i % 0x10) << 1;
+ field.msb = field.lsb + 1;
+
+ etzpc->fields[i] = devm_regmap_field_alloc(&pdev->dev,
+ regmap, field);
+ }
+
+ platform_set_drvdata(pdev, etzpc);
+
+ ret = firewall_register(dev_of_node(&pdev->dev),
+ &stm32_etzpc_ops,
+ &pdev->dev);
+ if (ret)
+ return ret;
+
+ stm32_etzpc_populate(&pdev->dev);
+
+ return 0;
+}
+
+static const struct of_device_id stm32_etzpc_of_match[] = {
+ { .compatible = "st,stm32-etzpc-bus" },
+ { /* end node */ }
+};
+MODULE_DEVICE_TABLE(of, stm32_etzpc_of_match);
+
+static struct platform_driver stm32_etzpc_driver = {
+ .probe = stm32_etzpc_probe,
+ .driver = {
+ .name = "stm32-etzpc",
+ .of_match_table = stm32_etzpc_of_match,
+ },
+};
+
+static int __init stm32_etzpc_init(void)
+{
+ return platform_driver_register(&stm32_etzpc_driver);
+}
+arch_initcall(stm32_etzpc_init);
+
+MODULE_AUTHOR("Benjamin Gaignard <benjamin.gaignard@xxxxxx>");
+MODULE_DESCRIPTION("STMicroelectronics STM32 Bus Firewall Controller");
diff --git a/include/dt-bindings/bus/stm32/stm32-etzpc.h b/include/dt-bindings/bus/stm32/stm32-etzpc.h
new file mode 100644
index 000000000000..9c4783b9783c
--- /dev/null
+++ b/include/dt-bindings/bus/stm32/stm32-etzpc.h
@@ -0,0 +1,90 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) STMicroelectronics 2020 - All Rights Reserved
+ * Author: Benjamin Gaignard <benjamin.gaignard@xxxxxx> for STMicroelectronics.
+ */
+
+#ifndef _STM32_ETZPC_H_
+#define _STM32_ETZPC_H_
+
+/* ETZPC configurations: trust-zone, non-secure or coprocessor*/
+#define STM32_ETZPC_TRUST 1
+#define STM32_ETPCZ_COPRO 2
+#define STM32_ETZPC_NON_SECURE 3
+
+/* ETZPC hard blocks index */
+#define STM32_ETZPC_USART1 3
+#define STM32_ETZPC_SPI6 4
+#define STM32_ETZPC_I2C4 5
+#define STM32_ETZPC_RNG1 7
+#define STM32_ETZPC_HASH1 8
+#define STM32_ETZPC_CRYP1 9
+#define STM32_ETZPC_I2C6 12
+#define STM32_ETZPC_TIM2 16
+#define STM32_ETZPC_TIM3 17
+#define STM32_ETZPC_TIM4 18
+#define STM32_ETZPC_TIM5 19
+#define STM32_ETZPC_TIM6 20
+#define STM32_ETZPC_TIM7 21
+#define STM32_ETZPC_TIM12 22
+#define STM32_ETZPC_TIM13 23
+#define STM32_ETZPC_TIM14 24
+#define STM32_ETZPC_LPTIM1 25
+#define STM32_ETZPC_SPI2 27
+#define STM32_ETZPC_SPI3 28
+#define STM32_ETZPC_USART2 30
+#define STM32_ETZPC_USART3 31
+#define STM32_ETZPC_USART4 32
+#define STM32_ETZPC_USART5 33
+#define STM32_ETZPC_I2C1 34
+#define STM32_ETZPC_I2C2 35
+#define STM32_ETZPC_I2C3 36
+#define STM32_ETZPC_I2C5 37
+#define STM32_ETZPC_CEC 38
+#define STM32_ETZPC_DAC 39
+#define STM32_ETZPC_UART7 40
+#define STM32_ETZPC_UART8 41
+#define STM32_ETZPC_MDIOS 44
+#define STM32_ETZPC_TIM1 48
+#define STM32_ETZPC_TIM8 49
+#define STM32_ETZPC_USART6 51
+#define STM32_ETZPC_SPI1 52
+#define STM32_ETZPC_SPI4 53
+#define STM32_ETZPC_TIM15 54
+#define STM32_ETZPC_TIM16 55
+#define STM32_ETZPC_TIM17 56
+#define STM32_ETZPC_SPI5 57
+#define STM32_ETZPC_SAI1 58
+#define STM32_ETZPC_SAI2 59
+#define STM32_ETZPC_SAI3 60
+#define STM32_ETZPC_DFSDM 61
+#define STM32_ETZPC_TT_FDCAN 62
+#define STM32_ETZPC_LPTIM2 64
+#define STM32_ETZPC_LPTIM3 65
+#define STM32_ETZPC_LPTIM4 66
+#define STM32_ETZPC_LPTIM5 67
+#define STM32_ETZPC_SAI4 68
+#define STM32_ETZPC_VREFBUF 69
+#define STM32_ETZPC_DCMI 70
+#define STM32_ETZPC_CRC2 71
+#define STM32_ETZPC_ADC 72
+#define STM32_ETZPC_HASH2 73
+#define STM32_ETZPC_RNG2 74
+#define STM32_ETZPC_CRYP2 75
+#define STM32_ETZPC_SRAM1 80
+#define STM32_ETZPC_SRAM2 81
+#define STM32_ETZPC_SRAM3 82
+#define STM32_ETZPC_SRAM4 83
+#define STM32_ETZPC_RETRAM 84
+#define STM32_ETZPC_OTG 85
+#define STM32_ETZPC_SDMMC3 86
+#define STM32_ETZPC_DLYBSD3 87
+#define STM32_ETZPC_DMA1 88
+#define STM32_ETZPC_DMA2 89
+#define STM32_ETZPC_DMAMUX 90
+#define STM32_ETZPC_FMC 91
+#define STM32_ETZPC_QSPI 92
+#define STM32_ETZPC_DLYBQ 93
+#define STM32_ETZPC_ETH1 94
+
+#endif /* _STM32_ETZPC_H_ */
--
2.15.0