RIFSC is a peripheral firewall controller that filter accesses based on Arm TrustZone secure state, Arm CPU privilege execution level and Compartment IDentification of the STM32 SoC subsystems.
Signed-off-by: Gatien Chevallier gatien.chevallier@foss.st.com ---
Changes in V4: Fix incorrect use of __set_bit() in stm32_rif_acquire_semaphore()
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_rifsc.c | 252 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 254 insertions(+), 1 deletion(-) create mode 100644 drivers/bus/stm32_rifsc.c
diff --git a/MAINTAINERS b/MAINTAINERS index 97d274ac005c..1f426414c37e 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -20140,6 +20140,7 @@ ST STM32 FIREWALL M: Gatien Chevallier gatien.chevallier@foss.st.com S: Maintained F: drivers/bus/stm32_firewall.c +F: drivers/bus/stm32_rifsc.c
ST STM32 I2C/SMBUS DRIVER M: Pierre-Yves MORDRET pierre-yves.mordret@foss.st.com diff --git a/drivers/bus/Makefile b/drivers/bus/Makefile index fc0511450ec2..e50d18e1d141 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-$(CONFIG_STM32_FIREWALL) += stm32_firewall.o +obj-$(CONFIG_STM32_FIREWALL) += stm32_firewall.o stm32_rifsc.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_rifsc.c b/drivers/bus/stm32_rifsc.c new file mode 100644 index 000000000000..4cf1b60014b7 --- /dev/null +++ b/drivers/bus/stm32_rifsc.c @@ -0,0 +1,252 @@ +// 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" + +/* + * RIFSC offset register + */ +#define RIFSC_RISC_SECCFGR0 0x10 +#define RIFSC_RISC_PRIVCFGR0 0x30 +#define RIFSC_RISC_PER0_CIDCFGR 0x100 +#define RIFSC_RISC_PER0_SEMCR 0x104 +#define RIFSC_RISC_HWCFGR2 0xFEC + +/* + * SEMCR register + */ +#define SEMCR_MUTEX BIT(0) + +/* + * HWCFGR2 register + */ +#define HWCFGR2_CONF1_MASK GENMASK(15, 0) +#define HWCFGR2_CONF2_MASK GENMASK(23, 16) +#define HWCFGR2_CONF3_MASK GENMASK(31, 24) + +/* + * RIFSC miscellaneous + */ +#define RIFSC_RISC_CFEN_MASK BIT(0) +#define RIFSC_RISC_SEM_EN_MASK BIT(1) +#define RIFSC_RISC_SCID_MASK GENMASK(6, 4) +#define RIFSC_RISC_SEML_SHIFT 16 +#define RIFSC_RISC_SEMWL_MASK GENMASK(23, 16) +#define RIFSC_RISC_PER_ID_MASK GENMASK(31, 24) + +#define RIFSC_RISC_PERx_CID_MASK (RIFSC_RISC_CFEN_MASK | \ + RIFSC_RISC_SEM_EN_MASK | \ + RIFSC_RISC_SCID_MASK | \ + RIFSC_RISC_SEMWL_MASK) + +#define IDS_PER_RISC_SEC_PRIV_REGS 32 + +/* RIF miscellaneous */ +/* + * CIDCFGR register fields + */ +#define CIDCFGR_CFEN BIT(0) +#define CIDCFGR_SEMEN BIT(1) +#define CIDCFGR_SEMWL(x) BIT(RIFSC_RISC_SEML_SHIFT + (x)) + +#define SEMWL_SHIFT 16 + +/* Compartiment IDs */ +#define RIF_CID0 0x0 +#define RIF_CID1 0x1 + +static bool stm32_rifsc_is_semaphore_available(void __iomem *addr) +{ + return !(readl(addr) & SEMCR_MUTEX); +} + +static int stm32_rif_acquire_semaphore(struct stm32_firewall_controller *stm32_firewall_controller, + int id) +{ + void __iomem *addr = stm32_firewall_controller->mmio + RIFSC_RISC_PER0_SEMCR + 0x8 * id; + + writel(SEMCR_MUTEX, addr); + + /* Check that CID1 has the semaphore */ + if (stm32_rifsc_is_semaphore_available(addr) || + FIELD_GET(RIFSC_RISC_SCID_MASK, readl(addr)) != RIF_CID1) + return -EACCES; + + return 0; +} + +static void stm32_rif_release_semaphore(struct stm32_firewall_controller *stm32_firewall_controller, + int id) +{ + void __iomem *addr = stm32_firewall_controller->mmio + RIFSC_RISC_PER0_SEMCR + 0x8 * id; + + if (stm32_rifsc_is_semaphore_available(addr)) + return; + + writel(SEMCR_MUTEX, addr); + + /* Ok if another compartment takes the semaphore before the check */ + WARN_ON(!stm32_rifsc_is_semaphore_available(addr) && + FIELD_GET(RIFSC_RISC_SCID_MASK, readl(addr)) == RIF_CID1); +} + +static int stm32_rifsc_grant_access(struct stm32_firewall_controller *ctrl, u32 firewall_id) +{ + struct stm32_firewall_controller *rifsc_controller = ctrl; + u32 reg_offset, reg_id, sec_reg_value, cid_reg_value; + int rc; + + if (firewall_id >= rifsc_controller->max_entries) { + dev_err(rifsc_controller->dev, "Invalid sys bus ID %u", firewall_id); + return -EINVAL; + } + + /* + * RIFSC_RISC_PRIVCFGRx and RIFSC_RISC_SECCFGRx both handle configuration access for + * 32 peripherals. On the other hand, there is one _RIFSC_RISC_PERx_CIDCFGR register + * per peripheral + */ + reg_id = firewall_id / IDS_PER_RISC_SEC_PRIV_REGS; + reg_offset = firewall_id % IDS_PER_RISC_SEC_PRIV_REGS; + sec_reg_value = readl(rifsc_controller->mmio + RIFSC_RISC_SECCFGR0 + 0x4 * reg_id); + cid_reg_value = readl(rifsc_controller->mmio + RIFSC_RISC_PER0_CIDCFGR + 0x8 * firewall_id); + + /* First check conditions for semaphore mode, which doesn't take into account static CID. */ + if ((cid_reg_value & CIDCFGR_SEMEN) && (cid_reg_value & CIDCFGR_CFEN)) { + if (cid_reg_value & BIT(RIF_CID1 + SEMWL_SHIFT)) { + /* Static CID is irrelevant if semaphore mode */ + goto skip_cid_check; + } else { + dev_dbg(rifsc_controller->dev, + "Invalid bus semaphore configuration: index %d\n", firewall_id); + return -EACCES; + } + } + + /* + * Skip CID check if CID filtering isn't enabled or filtering is enabled on CID0, which + * corresponds to whatever CID. + */ + if (!(cid_reg_value & CIDCFGR_CFEN) || + FIELD_GET(RIFSC_RISC_SCID_MASK, cid_reg_value) == RIF_CID0) + goto skip_cid_check; + + /* Coherency check with the CID configuration */ + if (FIELD_GET(RIFSC_RISC_SCID_MASK, cid_reg_value) != RIF_CID1) { + dev_dbg(rifsc_controller->dev, "Invalid CID configuration for peripheral: %d\n", + firewall_id); + return -EACCES; + } + +skip_cid_check: + /* Check security configuration */ + if (sec_reg_value & BIT(reg_offset)) { + dev_dbg(rifsc_controller->dev, + "Invalid security configuration for peripheral: %d\n", firewall_id); + return -EACCES; + } + + /* + * If the peripheral is in semaphore mode, take the semaphore so that + * the CID1 has the ownership. + */ + if ((cid_reg_value & CIDCFGR_SEMEN) && (cid_reg_value & CIDCFGR_CFEN)) { + rc = stm32_rif_acquire_semaphore(rifsc_controller, firewall_id); + if (rc) { + dev_err(rifsc_controller->dev, + "Couldn't acquire semaphore for peripheral: %d\n", firewall_id); + return rc; + } + } + + return 0; +} + +static void stm32_rifsc_release_access(struct stm32_firewall_controller *ctrl, u32 firewall_id) +{ + stm32_rif_release_semaphore(ctrl, firewall_id); +} + +static int stm32_rifsc_probe(struct platform_device *pdev) +{ + struct stm32_firewall_controller *rifsc_controller; + struct device_node *np = pdev->dev.of_node; + u32 nb_risup, nb_rimu, nb_risal; + struct resource *res; + void __iomem *mmio; + int rc; + + rifsc_controller = devm_kzalloc(&pdev->dev, sizeof(*rifsc_controller), GFP_KERNEL); + if (!rifsc_controller) + return -ENOMEM; + + mmio = devm_platform_get_and_ioremap_resource(pdev, 0, &res); + if (IS_ERR(mmio)) + return PTR_ERR(mmio); + + rifsc_controller->dev = &pdev->dev; + rifsc_controller->mmio = mmio; + rifsc_controller->name = dev_driver_string(rifsc_controller->dev); + rifsc_controller->type = STM32_PERIPHERAL_FIREWALL | STM32_MEMORY_FIREWALL; + rifsc_controller->grant_access = stm32_rifsc_grant_access; + rifsc_controller->release_access = stm32_rifsc_release_access; + + /* Get number of RIFSC entries*/ + nb_risup = readl(rifsc_controller->mmio + RIFSC_RISC_HWCFGR2) & HWCFGR2_CONF1_MASK; + nb_rimu = readl(rifsc_controller->mmio + RIFSC_RISC_HWCFGR2) & HWCFGR2_CONF2_MASK; + nb_risal = readl(rifsc_controller->mmio + RIFSC_RISC_HWCFGR2) & HWCFGR2_CONF3_MASK; + rifsc_controller->max_entries = nb_risup + nb_rimu + nb_risal; + + platform_set_drvdata(pdev, rifsc_controller); + + rc = stm32_firewall_controller_register(rifsc_controller); + if (rc) { + dev_err(rifsc_controller->dev, "Couldn't register as a firewall controller: %d", + rc); + return rc; + } + + rc = stm32_firewall_populate_bus(rifsc_controller); + if (rc) { + dev_err(rifsc_controller->dev, "Couldn't populate RIFSC 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_rifsc_of_match[] = { + { .compatible = "st,stm32mp25-rifsc" }, + {} +}; +MODULE_DEVICE_TABLE(of, stm32_rifsc_of_match); + +static struct platform_driver stm32_rifsc_driver = { + .probe = stm32_rifsc_probe, + .driver = { + .name = "stm32-rifsc", + .of_match_table = stm32_rifsc_of_match, + }, +}; +module_platform_driver(stm32_rifsc_driver); + +MODULE_AUTHOR("Gatien Chevallier gatien.chevallier@foss.st.com"); +MODULE_DESCRIPTION("STMicroelectronics RIFSC driver"); +MODULE_LICENSE("GPL");