ETZPC is a peripheral and memory firewall controller that filter accesses based on Arm TrustZone secure state and Arm CPU privilege execution level. It handles MCU isolation as well.
Signed-off-by: Gatien Chevallier gatien.chevallier@foss.st.com ---
Changes in V2: - Add controller name - Driver is now a module_platform_driver - Use error code returned by stm32_firewall_populate_bus() - Fix license
MAINTAINERS | 1 + drivers/bus/Makefile | 2 +- drivers/bus/stm32_etzpc.c | 141 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 143 insertions(+), 1 deletion(-) create mode 100644 drivers/bus/stm32_etzpc.c
diff --git a/MAINTAINERS b/MAINTAINERS index a1152438b52d..b83b471c8b73 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -20433,6 +20433,7 @@ F: drivers/media/i2c/st-mipid02.c ST STM32 FIREWALL M: Gatien Chevallier gatien.chevallier@foss.st.com S: Maintained +F: drivers/bus/stm32_etzpc.c F: drivers/bus/stm32_firewall.c F: drivers/bus/stm32_rifsc.c
diff --git a/drivers/bus/Makefile b/drivers/bus/Makefile index e50d18e1d141..cddd4984d6af 100644 --- a/drivers/bus/Makefile +++ b/drivers/bus/Makefile @@ -26,7 +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-$(CONFIG_STM32_FIREWALL) += stm32_firewall.o stm32_rifsc.o +obj-$(CONFIG_STM32_FIREWALL) += stm32_firewall.o stm32_rifsc.o stm32_etzpc.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_etzpc.c b/drivers/bus/stm32_etzpc.c new file mode 100644 index 000000000000..7fc0f16960be --- /dev/null +++ b/drivers/bus/stm32_etzpc.c @@ -0,0 +1,141 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2023, STMicroelectronics - All Rights Reserved + */ + +#include <linux/bitfield.h> +#include <linux/bits.h> +#include <linux/device.h> +#include <linux/err.h> +#include <linux/init.h> +#include <linux/io.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/types.h> + +#include "stm32_firewall.h" + +/* + * ETZPC registers + */ +#define ETZPC_DECPROT 0x10 +#define ETZPC_HWCFGR 0x3F0 + +/* + * HWCFGR register + */ +#define ETZPC_HWCFGR_NUM_TZMA GENMASK(7, 0) +#define ETZPC_HWCFGR_NUM_PER_SEC GENMASK(15, 8) +#define ETZPC_HWCFGR_NUM_AHB_SEC GENMASK(23, 16) +#define ETZPC_HWCFGR_CHUNKS1N4 GENMASK(31, 24) + +/* + * 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 + +static int stm32_etzpc_grant_access(struct stm32_firewall_controller *ctrl, u32 firewall_id) +{ + u32 offset, reg_offset, sec_val; + + if (firewall_id >= ctrl->max_entries) { + dev_err(ctrl->dev, "Invalid sys bus ID %u", firewall_id); + return -EINVAL; + } + + /* Check access configuration, 16 peripherals per register */ + reg_offset = ETZPC_DECPROT + 0x4 * (firewall_id / IDS_PER_DECPROT_REGS); + offset = (firewall_id % IDS_PER_DECPROT_REGS) << ETZPC_DECPROT_SHIFT; + + /* Verify peripheral is non-secure and attributed to cortex A7 */ + sec_val = (readl(ctrl->mmio + reg_offset) >> offset) & ETZPC_PROT_MASK; + if (sec_val != ETZPC_PROT_A7NS) { + dev_dbg(ctrl->dev, "Invalid bus configuration: reg_offset %#x, value %d\n", + reg_offset, sec_val); + return -EACCES; + } + + return 0; +} + +static void stm32_etzpc_release_access(struct stm32_firewall_controller *ctrl __maybe_unused, + u32 firewall_id __maybe_unused) +{ +} + +static int stm32_etzpc_probe(struct platform_device *pdev) +{ + struct stm32_firewall_controller *etzpc_controller; + struct device_node *np = pdev->dev.of_node; + u32 nb_per, nb_master; + struct resource *res; + void __iomem *mmio; + int rc; + + etzpc_controller = devm_kzalloc(&pdev->dev, sizeof(*etzpc_controller), GFP_KERNEL); + if (!etzpc_controller) + return -ENOMEM; + + mmio = devm_platform_get_and_ioremap_resource(pdev, 0, &res); + if (IS_ERR(mmio)) + return PTR_ERR(mmio); + + etzpc_controller->dev = &pdev->dev; + etzpc_controller->mmio = mmio; + etzpc_controller->name = dev_driver_string(etzpc_controller->dev); + etzpc_controller->type = STM32_PERIPHERAL_FIREWALL | STM32_MEMORY_FIREWALL; + etzpc_controller->grant_access = stm32_etzpc_grant_access; + etzpc_controller->release_access = stm32_etzpc_release_access; + + /* Get number of etzpc entries*/ + nb_per = FIELD_GET(ETZPC_HWCFGR_NUM_PER_SEC, + readl(etzpc_controller->mmio + ETZPC_HWCFGR)); + nb_master = FIELD_GET(ETZPC_HWCFGR_NUM_AHB_SEC, + readl(etzpc_controller->mmio + ETZPC_HWCFGR)); + etzpc_controller->max_entries = nb_per + nb_master; + + platform_set_drvdata(pdev, etzpc_controller); + + rc = stm32_firewall_controller_register(etzpc_controller); + if (rc) { + dev_err(etzpc_controller->dev, "Couldn't register as a firewall controller: %d", + rc); + return rc; + } + + rc = stm32_firewall_populate_bus(etzpc_controller); + if (rc) { + dev_err(etzpc_controller->dev, "Couldn't populate ETZPC bus: %d", + rc); + return rc; + } + + /* Populate all allowed nodes */ + return of_platform_populate(np, NULL, NULL, &pdev->dev); +} + +static const struct of_device_id stm32_etzpc_of_match[] = { + { .compatible = "st,stm32-etzpc" }, + {} +}; +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, + }, +}; +module_platform_driver(stm32_etzpc_driver); + +MODULE_AUTHOR("Gatien Chevallier gatien.chevallier@foss.st.com"); +MODULE_DESCRIPTION("STMicroelectronics ETZPC driver"); +MODULE_LICENSE("GPL");