1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2023, STMicroelectronics - All Rights Reserved 4 */ 5 6 #include <linux/bitfield.h> 7 #include <linux/bits.h> 8 #include <linux/device.h> 9 #include <linux/err.h> 10 #include <linux/init.h> 11 #include <linux/io.h> 12 #include <linux/kernel.h> 13 #include <linux/module.h> 14 #include <linux/of.h> 15 #include <linux/of_platform.h> 16 #include <linux/platform_device.h> 17 #include <linux/types.h> 18 19 #include "stm32_firewall.h" 20 21 /* 22 * ETZPC registers 23 */ 24 #define ETZPC_DECPROT 0x10 25 #define ETZPC_HWCFGR 0x3F0 26 27 /* 28 * HWCFGR register 29 */ 30 #define ETZPC_HWCFGR_NUM_TZMA GENMASK(7, 0) 31 #define ETZPC_HWCFGR_NUM_PER_SEC GENMASK(15, 8) 32 #define ETZPC_HWCFGR_NUM_AHB_SEC GENMASK(23, 16) 33 #define ETZPC_HWCFGR_CHUNKS1N4 GENMASK(31, 24) 34 35 /* 36 * ETZPC miscellaneous 37 */ 38 #define ETZPC_PROT_MASK GENMASK(1, 0) 39 #define ETZPC_PROT_A7NS 0x3 40 #define ETZPC_DECPROT_SHIFT 1 41 42 #define IDS_PER_DECPROT_REGS 16 43 44 static int stm32_etzpc_grant_access(struct stm32_firewall_controller *ctrl, u32 firewall_id) 45 { 46 u32 offset, reg_offset, sec_val; 47 48 if (firewall_id >= ctrl->max_entries) { 49 dev_err(ctrl->dev, "Invalid sys bus ID %u", firewall_id); 50 return -EINVAL; 51 } 52 53 /* Check access configuration, 16 peripherals per register */ 54 reg_offset = ETZPC_DECPROT + 0x4 * (firewall_id / IDS_PER_DECPROT_REGS); 55 offset = (firewall_id % IDS_PER_DECPROT_REGS) << ETZPC_DECPROT_SHIFT; 56 57 /* Verify peripheral is non-secure and attributed to cortex A7 */ 58 sec_val = (readl(ctrl->mmio + reg_offset) >> offset) & ETZPC_PROT_MASK; 59 if (sec_val != ETZPC_PROT_A7NS) { 60 dev_dbg(ctrl->dev, "Invalid bus configuration: reg_offset %#x, value %d\n", 61 reg_offset, sec_val); 62 return -EACCES; 63 } 64 65 return 0; 66 } 67 68 static void stm32_etzpc_release_access(struct stm32_firewall_controller *ctrl __maybe_unused, 69 u32 firewall_id __maybe_unused) 70 { 71 } 72 73 static int stm32_etzpc_probe(struct platform_device *pdev) 74 { 75 struct stm32_firewall_controller *etzpc_controller; 76 struct device_node *np = pdev->dev.of_node; 77 u32 nb_per, nb_master; 78 struct resource *res; 79 void __iomem *mmio; 80 int rc; 81 82 etzpc_controller = devm_kzalloc(&pdev->dev, sizeof(*etzpc_controller), GFP_KERNEL); 83 if (!etzpc_controller) 84 return -ENOMEM; 85 86 mmio = devm_platform_get_and_ioremap_resource(pdev, 0, &res); 87 if (IS_ERR(mmio)) 88 return PTR_ERR(mmio); 89 90 etzpc_controller->dev = &pdev->dev; 91 etzpc_controller->mmio = mmio; 92 etzpc_controller->name = dev_driver_string(etzpc_controller->dev); 93 etzpc_controller->type = STM32_PERIPHERAL_FIREWALL | STM32_MEMORY_FIREWALL; 94 etzpc_controller->grant_access = stm32_etzpc_grant_access; 95 etzpc_controller->release_access = stm32_etzpc_release_access; 96 97 /* Get number of etzpc entries*/ 98 nb_per = FIELD_GET(ETZPC_HWCFGR_NUM_PER_SEC, 99 readl(etzpc_controller->mmio + ETZPC_HWCFGR)); 100 nb_master = FIELD_GET(ETZPC_HWCFGR_NUM_AHB_SEC, 101 readl(etzpc_controller->mmio + ETZPC_HWCFGR)); 102 etzpc_controller->max_entries = nb_per + nb_master; 103 104 platform_set_drvdata(pdev, etzpc_controller); 105 106 rc = stm32_firewall_controller_register(etzpc_controller); 107 if (rc) { 108 dev_err(etzpc_controller->dev, "Couldn't register as a firewall controller: %d", 109 rc); 110 return rc; 111 } 112 113 rc = stm32_firewall_populate_bus(etzpc_controller); 114 if (rc) { 115 dev_err(etzpc_controller->dev, "Couldn't populate ETZPC bus: %d", 116 rc); 117 return rc; 118 } 119 120 /* Populate all allowed nodes */ 121 return of_platform_populate(np, NULL, NULL, &pdev->dev); 122 } 123 124 static const struct of_device_id stm32_etzpc_of_match[] = { 125 { .compatible = "st,stm32-etzpc" }, 126 {} 127 }; 128 MODULE_DEVICE_TABLE(of, stm32_etzpc_of_match); 129 130 static struct platform_driver stm32_etzpc_driver = { 131 .probe = stm32_etzpc_probe, 132 .driver = { 133 .name = "stm32-etzpc", 134 .of_match_table = stm32_etzpc_of_match, 135 }, 136 }; 137 module_platform_driver(stm32_etzpc_driver); 138 139 MODULE_AUTHOR("Gatien Chevallier <gatien.chevallier@foss.st.com>"); 140 MODULE_DESCRIPTION("STMicroelectronics ETZPC driver"); 141 MODULE_LICENSE("GPL"); 142