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