1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2016 Imagination Technologies
4  * Author: Paul Burton <paul.burton@mips.com>
5  */
6 
7 #define pr_fmt(fmt) "sead3: " fmt
8 
9 #include <linux/errno.h>
10 #include <linux/libfdt.h>
11 #include <linux/printk.h>
12 #include <linux/sizes.h>
13 
14 #include <asm/fw/fw.h>
15 #include <asm/io.h>
16 #include <asm/machine.h>
17 #include <asm/yamon-dt.h>
18 
19 #define SEAD_CONFIG			CKSEG1ADDR(0x1b100110)
20 #define SEAD_CONFIG_GIC_PRESENT		BIT(1)
21 
22 #define MIPS_REVISION			CKSEG1ADDR(0x1fc00010)
23 #define MIPS_REVISION_MACHINE		(0xf << 4)
24 #define MIPS_REVISION_MACHINE_SEAD3	(0x4 << 4)
25 
26 /*
27  * Maximum 384MB RAM at physical address 0, preceding any I/O.
28  */
29 static struct yamon_mem_region mem_regions[] __initdata = {
30 	/* start	size */
31 	{ 0,		SZ_256M + SZ_128M },
32 	{}
33 };
34 
sead3_detect(void)35 static __init bool sead3_detect(void)
36 {
37 	uint32_t rev;
38 
39 	rev = __raw_readl((void *)MIPS_REVISION);
40 	return (rev & MIPS_REVISION_MACHINE) == MIPS_REVISION_MACHINE_SEAD3;
41 }
42 
append_memory(void * fdt)43 static __init int append_memory(void *fdt)
44 {
45 	return yamon_dt_append_memory(fdt, mem_regions);
46 }
47 
remove_gic(void * fdt)48 static __init int remove_gic(void *fdt)
49 {
50 	const unsigned int cpu_ehci_int = 2;
51 	const unsigned int cpu_uart_int = 4;
52 	const unsigned int cpu_eth_int = 6;
53 	int gic_off, cpu_off, uart_off, eth_off, ehci_off, err;
54 	uint32_t cfg, cpu_phandle;
55 
56 	/* leave the GIC node intact if a GIC is present */
57 	cfg = __raw_readl((uint32_t *)SEAD_CONFIG);
58 	if (cfg & SEAD_CONFIG_GIC_PRESENT)
59 		return 0;
60 
61 	gic_off = fdt_node_offset_by_compatible(fdt, -1, "mti,gic");
62 	if (gic_off < 0) {
63 		pr_err("unable to find DT GIC node: %d\n", gic_off);
64 		return gic_off;
65 	}
66 
67 	err = fdt_nop_node(fdt, gic_off);
68 	if (err) {
69 		pr_err("unable to nop GIC node\n");
70 		return err;
71 	}
72 
73 	cpu_off = fdt_node_offset_by_compatible(fdt, -1,
74 			"mti,cpu-interrupt-controller");
75 	if (cpu_off < 0) {
76 		pr_err("unable to find CPU intc node: %d\n", cpu_off);
77 		return cpu_off;
78 	}
79 
80 	cpu_phandle = fdt_get_phandle(fdt, cpu_off);
81 	if (!cpu_phandle) {
82 		pr_err("unable to get CPU intc phandle\n");
83 		return -EINVAL;
84 	}
85 
86 	uart_off = fdt_node_offset_by_compatible(fdt, -1, "ns16550a");
87 	while (uart_off >= 0) {
88 		err = fdt_setprop_u32(fdt, uart_off, "interrupt-parent",
89 				      cpu_phandle);
90 		if (err) {
91 			pr_warn("unable to set UART interrupt-parent: %d\n",
92 				err);
93 			return err;
94 		}
95 
96 		err = fdt_setprop_u32(fdt, uart_off, "interrupts",
97 				      cpu_uart_int);
98 		if (err) {
99 			pr_err("unable to set UART interrupts property: %d\n",
100 			       err);
101 			return err;
102 		}
103 
104 		uart_off = fdt_node_offset_by_compatible(fdt, uart_off,
105 							 "ns16550a");
106 	}
107 	if (uart_off != -FDT_ERR_NOTFOUND) {
108 		pr_err("error searching for UART DT node: %d\n", uart_off);
109 		return uart_off;
110 	}
111 
112 	eth_off = fdt_node_offset_by_compatible(fdt, -1, "smsc,lan9115");
113 	if (eth_off < 0) {
114 		pr_err("unable to find ethernet DT node: %d\n", eth_off);
115 		return eth_off;
116 	}
117 
118 	err = fdt_setprop_u32(fdt, eth_off, "interrupt-parent", cpu_phandle);
119 	if (err) {
120 		pr_err("unable to set ethernet interrupt-parent: %d\n", err);
121 		return err;
122 	}
123 
124 	err = fdt_setprop_u32(fdt, eth_off, "interrupts", cpu_eth_int);
125 	if (err) {
126 		pr_err("unable to set ethernet interrupts property: %d\n", err);
127 		return err;
128 	}
129 
130 	ehci_off = fdt_node_offset_by_compatible(fdt, -1, "generic-ehci");
131 	if (ehci_off < 0) {
132 		pr_err("unable to find EHCI DT node: %d\n", ehci_off);
133 		return ehci_off;
134 	}
135 
136 	err = fdt_setprop_u32(fdt, ehci_off, "interrupt-parent", cpu_phandle);
137 	if (err) {
138 		pr_err("unable to set EHCI interrupt-parent: %d\n", err);
139 		return err;
140 	}
141 
142 	err = fdt_setprop_u32(fdt, ehci_off, "interrupts", cpu_ehci_int);
143 	if (err) {
144 		pr_err("unable to set EHCI interrupts property: %d\n", err);
145 		return err;
146 	}
147 
148 	return 0;
149 }
150 
151 static const struct mips_fdt_fixup sead3_fdt_fixups[] __initconst = {
152 	{ yamon_dt_append_cmdline, "append command line" },
153 	{ append_memory, "append memory" },
154 	{ remove_gic, "remove GIC when not present" },
155 	{ yamon_dt_serial_config, "append serial configuration" },
156 	{ },
157 };
158 
sead3_fixup_fdt(const void * fdt,const void * match_data)159 static __init const void *sead3_fixup_fdt(const void *fdt,
160 					  const void *match_data)
161 {
162 	static unsigned char fdt_buf[16 << 10] __initdata;
163 	int err;
164 
165 	if (fdt_check_header(fdt))
166 		panic("Corrupt DT");
167 
168 	/* if this isn't SEAD3, something went wrong */
169 	BUG_ON(fdt_node_check_compatible(fdt, 0, "mti,sead-3"));
170 
171 	fw_init_cmdline();
172 
173 	err = apply_mips_fdt_fixups(fdt_buf, sizeof(fdt_buf),
174 				    fdt, sead3_fdt_fixups);
175 	if (err)
176 		panic("Unable to fixup FDT: %d", err);
177 
178 	return fdt_buf;
179 }
180 
sead3_measure_hpt_freq(void)181 static __init unsigned int sead3_measure_hpt_freq(void)
182 {
183 	void __iomem *status_reg = (void __iomem *)0xbf000410;
184 	unsigned int freq, orig, tick = 0;
185 	unsigned long flags;
186 
187 	local_irq_save(flags);
188 
189 	orig = readl(status_reg) & 0x2;		      /* get original sample */
190 	/* wait for transition */
191 	while ((readl(status_reg) & 0x2) == orig)
192 		;
193 	orig = orig ^ 0x2;			      /* flip the bit */
194 
195 	write_c0_count(0);
196 
197 	/* wait 1 second (the sampling clock transitions every 10ms) */
198 	while (tick < 100) {
199 		/* wait for transition */
200 		while ((readl(status_reg) & 0x2) == orig)
201 			;
202 		orig = orig ^ 0x2;			      /* flip the bit */
203 		tick++;
204 	}
205 
206 	freq = read_c0_count();
207 
208 	local_irq_restore(flags);
209 
210 	return freq;
211 }
212 
213 extern char __dtb_sead3_begin[];
214 
215 MIPS_MACHINE(sead3) = {
216 	.fdt = __dtb_sead3_begin,
217 	.detect = sead3_detect,
218 	.fixup_fdt = sead3_fixup_fdt,
219 	.measure_hpt_freq = sead3_measure_hpt_freq,
220 };
221