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
stm32_etzpc_grant_access(struct stm32_firewall_controller * ctrl,u32 firewall_id)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
stm32_etzpc_release_access(struct stm32_firewall_controller * ctrl __maybe_unused,u32 firewall_id __maybe_unused)68 static void stm32_etzpc_release_access(struct stm32_firewall_controller *ctrl __maybe_unused,
69 u32 firewall_id __maybe_unused)
70 {
71 }
72
stm32_etzpc_probe(struct platform_device * pdev)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