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  1/*
  2 * Copyright (C) 2016 Imagination Technologies
  3 * Author: Paul Burton <paul.burton@imgtec.com>
  4 *
  5 * This program is free software; you can redistribute it and/or modify it
  6 * under the terms of the GNU General Public License as published by the
  7 * Free Software Foundation;  either version 2 of the  License, or (at your
  8 * option) any later version.
  9 */
 10
 11#define pr_fmt(fmt) "sead3: " fmt
 12
 13#include <linux/errno.h>
 14#include <linux/libfdt.h>
 15#include <linux/printk.h>
 16
 17#include <asm/fw/fw.h>
 18#include <asm/io.h>
 19#include <asm/machine.h>
 20
 21#define SEAD_CONFIG			CKSEG1ADDR(0x1b100110)
 22#define SEAD_CONFIG_GIC_PRESENT		BIT(1)
 23
 24#define MIPS_REVISION			CKSEG1ADDR(0x1fc00010)
 25#define MIPS_REVISION_MACHINE		(0xf << 4)
 26#define MIPS_REVISION_MACHINE_SEAD3	(0x4 << 4)
 27
 28static __init bool sead3_detect(void)
 29{
 30	uint32_t rev;
 31
 32	rev = __raw_readl((void *)MIPS_REVISION);
 33	return (rev & MIPS_REVISION_MACHINE) == MIPS_REVISION_MACHINE_SEAD3;
 34}
 35
 36static __init int append_cmdline(void *fdt)
 37{
 38	int err, chosen_off;
 39
 40	/* find or add chosen node */
 41	chosen_off = fdt_path_offset(fdt, "/chosen");
 42	if (chosen_off == -FDT_ERR_NOTFOUND)
 43		chosen_off = fdt_path_offset(fdt, "/chosen@0");
 44	if (chosen_off == -FDT_ERR_NOTFOUND)
 45		chosen_off = fdt_add_subnode(fdt, 0, "chosen");
 46	if (chosen_off < 0) {
 47		pr_err("Unable to find or add DT chosen node: %d\n",
 48		       chosen_off);
 49		return chosen_off;
 50	}
 51
 52	err = fdt_setprop_string(fdt, chosen_off, "bootargs", fw_getcmdline());
 53	if (err) {
 54		pr_err("Unable to set bootargs property: %d\n", err);
 55		return err;
 56	}
 57
 58	return 0;
 59}
 60
 61static __init int append_memory(void *fdt)
 62{
 63	unsigned long phys_memsize, memsize;
 64	__be32 mem_array[2];
 65	int err, mem_off;
 66	char *var;
 67
 68	/* find memory size from the bootloader environment */
 69	var = fw_getenv("memsize");
 70	if (var) {
 71		err = kstrtoul(var, 0, &phys_memsize);
 72		if (err) {
 73			pr_err("Failed to read memsize env variable '%s'\n",
 74			       var);
 75			return -EINVAL;
 76		}
 77	} else {
 78		pr_warn("The bootloader didn't provide memsize: defaulting to 32MB\n");
 79		phys_memsize = 32 << 20;
 80	}
 81
 82	/* default to using all available RAM */
 83	memsize = phys_memsize;
 84
 85	/* allow the user to override the usable memory */
 86	var = strstr(arcs_cmdline, "memsize=");
 87	if (var)
 88		memsize = memparse(var + strlen("memsize="), NULL);
 89
 90	/* if the user says there's more RAM than we thought, believe them */
 91	phys_memsize = max_t(unsigned long, phys_memsize, memsize);
 92
 93	/* find or add a memory node */
 94	mem_off = fdt_path_offset(fdt, "/memory");
 95	if (mem_off == -FDT_ERR_NOTFOUND)
 96		mem_off = fdt_add_subnode(fdt, 0, "memory");
 97	if (mem_off < 0) {
 98		pr_err("Unable to find or add memory DT node: %d\n", mem_off);
 99		return mem_off;
100	}
101
102	err = fdt_setprop_string(fdt, mem_off, "device_type", "memory");
103	if (err) {
104		pr_err("Unable to set memory node device_type: %d\n", err);
105		return err;
106	}
107
108	mem_array[0] = 0;
109	mem_array[1] = cpu_to_be32(phys_memsize);
110	err = fdt_setprop(fdt, mem_off, "reg", mem_array, sizeof(mem_array));
111	if (err) {
112		pr_err("Unable to set memory regs property: %d\n", err);
113		return err;
114	}
115
116	mem_array[0] = 0;
117	mem_array[1] = cpu_to_be32(memsize);
118	err = fdt_setprop(fdt, mem_off, "linux,usable-memory",
119			  mem_array, sizeof(mem_array));
120	if (err) {
121		pr_err("Unable to set linux,usable-memory property: %d\n", err);
122		return err;
123	}
124
125	return 0;
126}
127
128static __init int remove_gic(void *fdt)
129{
130	const unsigned int cpu_ehci_int = 2;
131	const unsigned int cpu_uart_int = 4;
132	const unsigned int cpu_eth_int = 6;
133	int gic_off, cpu_off, uart_off, eth_off, ehci_off, err;
134	uint32_t cfg, cpu_phandle;
135
136	/* leave the GIC node intact if a GIC is present */
137	cfg = __raw_readl((uint32_t *)SEAD_CONFIG);
138	if (cfg & SEAD_CONFIG_GIC_PRESENT)
139		return 0;
140
141	gic_off = fdt_node_offset_by_compatible(fdt, -1, "mti,gic");
142	if (gic_off < 0) {
143		pr_err("unable to find DT GIC node: %d\n", gic_off);
144		return gic_off;
145	}
146
147	err = fdt_nop_node(fdt, gic_off);
148	if (err) {
149		pr_err("unable to nop GIC node\n");
150		return err;
151	}
152
153	cpu_off = fdt_node_offset_by_compatible(fdt, -1,
154			"mti,cpu-interrupt-controller");
155	if (cpu_off < 0) {
156		pr_err("unable to find CPU intc node: %d\n", cpu_off);
157		return cpu_off;
158	}
159
160	cpu_phandle = fdt_get_phandle(fdt, cpu_off);
161	if (!cpu_phandle) {
162		pr_err("unable to get CPU intc phandle\n");
163		return -EINVAL;
164	}
165
166	err = fdt_setprop_u32(fdt, 0, "interrupt-parent", cpu_phandle);
167	if (err) {
168		pr_err("unable to set root interrupt-parent: %d\n", err);
169		return err;
170	}
171
172	uart_off = fdt_node_offset_by_compatible(fdt, -1, "ns16550a");
173	while (uart_off >= 0) {
174		err = fdt_setprop_u32(fdt, uart_off, "interrupts",
175				      cpu_uart_int);
176		if (err) {
177			pr_err("unable to set UART interrupts property: %d\n",
178			       err);
179			return err;
180		}
181
182		uart_off = fdt_node_offset_by_compatible(fdt, uart_off,
183							 "ns16550a");
184	}
185	if (uart_off != -FDT_ERR_NOTFOUND) {
186		pr_err("error searching for UART DT node: %d\n", uart_off);
187		return uart_off;
188	}
189
190	eth_off = fdt_node_offset_by_compatible(fdt, -1, "smsc,lan9115");
191	if (eth_off < 0) {
192		pr_err("unable to find ethernet DT node: %d\n", eth_off);
193		return eth_off;
194	}
195
196	err = fdt_setprop_u32(fdt, eth_off, "interrupts", cpu_eth_int);
197	if (err) {
198		pr_err("unable to set ethernet interrupts property: %d\n", err);
199		return err;
200	}
201
202	ehci_off = fdt_node_offset_by_compatible(fdt, -1, "generic-ehci");
203	if (ehci_off < 0) {
204		pr_err("unable to find EHCI DT node: %d\n", ehci_off);
205		return ehci_off;
206	}
207
208	err = fdt_setprop_u32(fdt, ehci_off, "interrupts", cpu_ehci_int);
209	if (err) {
210		pr_err("unable to set EHCI interrupts property: %d\n", err);
211		return err;
212	}
213
214	return 0;
215}
216
217static __init int serial_config(void *fdt)
218{
219	const char *yamontty, *mode_var;
220	char mode_var_name[9], path[18], parity;
221	unsigned int uart, baud, stop_bits;
222	bool hw_flow;
223	int chosen_off, err;
224
225	yamontty = fw_getenv("yamontty");
226	if (!yamontty || !strcmp(yamontty, "tty0")) {
227		uart = 0;
228	} else if (!strcmp(yamontty, "tty1")) {
229		uart = 1;
230	} else {
231		pr_warn("yamontty environment variable '%s' invalid\n",
232			yamontty);
233		uart = 0;
234	}
235
236	baud = stop_bits = 0;
237	parity = 0;
238	hw_flow = false;
239
240	snprintf(mode_var_name, sizeof(mode_var_name), "modetty%u", uart);
241	mode_var = fw_getenv(mode_var_name);
242	if (mode_var) {
243		while (mode_var[0] >= '0' && mode_var[0] <= '9') {
244			baud *= 10;
245			baud += mode_var[0] - '0';
246			mode_var++;
247		}
248		if (mode_var[0] == ',')
249			mode_var++;
250		if (mode_var[0])
251			parity = mode_var[0];
252		if (mode_var[0] == ',')
253			mode_var++;
254		if (mode_var[0])
255			stop_bits = mode_var[0] - '0';
256		if (mode_var[0] == ',')
257			mode_var++;
258		if (!strcmp(mode_var, "hw"))
259			hw_flow = true;
260	}
261
262	if (!baud)
263		baud = 38400;
264
265	if (parity != 'e' && parity != 'n' && parity != 'o')
266		parity = 'n';
267
268	if (stop_bits != 7 && stop_bits != 8)
269		stop_bits = 8;
270
271	WARN_ON(snprintf(path, sizeof(path), "uart%u:%u%c%u%s",
272			 uart, baud, parity, stop_bits,
273			 hw_flow ? "r" : "") >= sizeof(path));
274
275	/* find or add chosen node */
276	chosen_off = fdt_path_offset(fdt, "/chosen");
277	if (chosen_off == -FDT_ERR_NOTFOUND)
278		chosen_off = fdt_path_offset(fdt, "/chosen@0");
279	if (chosen_off == -FDT_ERR_NOTFOUND)
280		chosen_off = fdt_add_subnode(fdt, 0, "chosen");
281	if (chosen_off < 0) {
282		pr_err("Unable to find or add DT chosen node: %d\n",
283		       chosen_off);
284		return chosen_off;
285	}
286
287	err = fdt_setprop_string(fdt, chosen_off, "stdout-path", path);
288	if (err) {
289		pr_err("Unable to set stdout-path property: %d\n", err);
290		return err;
291	}
292
293	return 0;
294}
295
296static __init const void *sead3_fixup_fdt(const void *fdt,
297					  const void *match_data)
298{
299	static unsigned char fdt_buf[16 << 10] __initdata;
300	int err;
301
302	if (fdt_check_header(fdt))
303		panic("Corrupt DT");
304
305	/* if this isn't SEAD3, something went wrong */
306	BUG_ON(fdt_node_check_compatible(fdt, 0, "mti,sead-3"));
307
308	fw_init_cmdline();
309
310	err = fdt_open_into(fdt, fdt_buf, sizeof(fdt_buf));
311	if (err)
312		panic("Unable to open FDT: %d", err);
313
314	err = append_cmdline(fdt_buf);
315	if (err)
316		panic("Unable to patch FDT: %d", err);
317
318	err = append_memory(fdt_buf);
319	if (err)
320		panic("Unable to patch FDT: %d", err);
321
322	err = remove_gic(fdt_buf);
323	if (err)
324		panic("Unable to patch FDT: %d", err);
325
326	err = serial_config(fdt_buf);
327	if (err)
328		panic("Unable to patch FDT: %d", err);
329
330	err = fdt_pack(fdt_buf);
331	if (err)
332		panic("Unable to pack FDT: %d\n", err);
333
334	return fdt_buf;
335}
336
337static __init unsigned int sead3_measure_hpt_freq(void)
338{
339	void __iomem *status_reg = (void __iomem *)0xbf000410;
340	unsigned int freq, orig, tick = 0;
341	unsigned long flags;
342
343	local_irq_save(flags);
344
345	orig = readl(status_reg) & 0x2;		      /* get original sample */
346	/* wait for transition */
347	while ((readl(status_reg) & 0x2) == orig)
348		;
349	orig = orig ^ 0x2;			      /* flip the bit */
350
351	write_c0_count(0);
352
353	/* wait 1 second (the sampling clock transitions every 10ms) */
354	while (tick < 100) {
355		/* wait for transition */
356		while ((readl(status_reg) & 0x2) == orig)
357			;
358		orig = orig ^ 0x2;			      /* flip the bit */
359		tick++;
360	}
361
362	freq = read_c0_count();
363
364	local_irq_restore(flags);
365
366	return freq;
367}
368
369extern char __dtb_sead3_begin[];
370
371MIPS_MACHINE(sead3) = {
372	.fdt = __dtb_sead3_begin,
373	.detect = sead3_detect,
374	.fixup_fdt = sead3_fixup_fdt,
375	.measure_hpt_freq = sead3_measure_hpt_freq,
376};