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
44static 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
68static void stm32_etzpc_release_access(struct stm32_firewall_controller *ctrl __maybe_unused,
69				       u32 firewall_id __maybe_unused)
70{
71}
72
73static 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
124static const struct of_device_id stm32_etzpc_of_match[] = {
125	{ .compatible = "st,stm32-etzpc" },
126	{}
127};
128MODULE_DEVICE_TABLE(of, stm32_etzpc_of_match);
129
130static 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};
137module_platform_driver(stm32_etzpc_driver);
138
139MODULE_AUTHOR("Gatien Chevallier <gatien.chevallier@foss.st.com>");
140MODULE_DESCRIPTION("STMicroelectronics ETZPC driver");
141MODULE_LICENSE("GPL");
142