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df0ac8a4 KC |
1 | /* |
2 | * This file is subject to the terms and conditions of the GNU General Public | |
3 | * License. See the file "COPYING" in the main directory of this archive | |
4 | * for more details. | |
5 | * | |
6 | * Copyright (C) 2011 by Kevin Cernekee (cernekee@gmail.com) | |
7 | * | |
8 | * SMP support for BMIPS | |
9 | */ | |
10 | ||
df0ac8a4 KC |
11 | #include <linux/init.h> |
12 | #include <linux/sched.h> | |
13 | #include <linux/mm.h> | |
14 | #include <linux/delay.h> | |
15 | #include <linux/smp.h> | |
16 | #include <linux/interrupt.h> | |
17 | #include <linux/spinlock.h> | |
df0ac8a4 KC |
18 | #include <linux/cpu.h> |
19 | #include <linux/cpumask.h> | |
20 | #include <linux/reboot.h> | |
21 | #include <linux/io.h> | |
22 | #include <linux/compiler.h> | |
23 | #include <linux/linkage.h> | |
24 | #include <linux/bug.h> | |
25 | #include <linux/kernel.h> | |
26 | ||
27 | #include <asm/time.h> | |
28 | #include <asm/pgtable.h> | |
29 | #include <asm/processor.h> | |
df0ac8a4 KC |
30 | #include <asm/bootinfo.h> |
31 | #include <asm/pmon.h> | |
32 | #include <asm/cacheflush.h> | |
33 | #include <asm/tlbflush.h> | |
34 | #include <asm/mipsregs.h> | |
35 | #include <asm/bmips.h> | |
36 | #include <asm/traps.h> | |
37 | #include <asm/barrier.h> | |
38 | ||
39 | static int __maybe_unused max_cpus = 1; | |
40 | ||
41 | /* these may be configured by the platform code */ | |
42 | int bmips_smp_enabled = 1; | |
43 | int bmips_cpu_offset; | |
44 | cpumask_t bmips_booted_mask; | |
45 | ||
46 | #ifdef CONFIG_SMP | |
47 | ||
48 | /* initial $sp, $gp - used by arch/mips/kernel/bmips_vec.S */ | |
49 | unsigned long bmips_smp_boot_sp; | |
50 | unsigned long bmips_smp_boot_gp; | |
51 | ||
52 | static void bmips_send_ipi_single(int cpu, unsigned int action); | |
53 | static irqreturn_t bmips_ipi_interrupt(int irq, void *dev_id); | |
54 | ||
55 | /* SW interrupts 0,1 are used for interprocessor signaling */ | |
56 | #define IPI0_IRQ (MIPS_CPU_IRQ_BASE + 0) | |
57 | #define IPI1_IRQ (MIPS_CPU_IRQ_BASE + 1) | |
58 | ||
59 | #define CPUNUM(cpu, shift) (((cpu) + bmips_cpu_offset) << (shift)) | |
60 | #define ACTION_CLR_IPI(cpu, ipi) (0x2000 | CPUNUM(cpu, 9) | ((ipi) << 8)) | |
61 | #define ACTION_SET_IPI(cpu, ipi) (0x3000 | CPUNUM(cpu, 9) | ((ipi) << 8)) | |
62 | #define ACTION_BOOT_THREAD(cpu) (0x08 | CPUNUM(cpu, 0)) | |
63 | ||
64 | static void __init bmips_smp_setup(void) | |
65 | { | |
66 | int i; | |
67 | ||
68 | #if defined(CONFIG_CPU_BMIPS4350) || defined(CONFIG_CPU_BMIPS4380) | |
69 | /* arbitration priority */ | |
70 | clear_c0_brcm_cmt_ctrl(0x30); | |
71 | ||
72 | /* NBK and weak order flags */ | |
73 | set_c0_brcm_config_0(0x30000); | |
74 | ||
75 | /* | |
76 | * MIPS interrupts 0,1 (SW INT 0,1) cross over to the other thread | |
77 | * MIPS interrupt 2 (HW INT 0) is the CPU0 L1 controller output | |
78 | * MIPS interrupt 3 (HW INT 1) is the CPU1 L1 controller output | |
79 | */ | |
80 | change_c0_brcm_cmt_intr(0xf8018000, | |
81 | (0x02 << 27) | (0x03 << 15)); | |
82 | ||
83 | /* single core, 2 threads (2 pipelines) */ | |
84 | max_cpus = 2; | |
85 | #elif defined(CONFIG_CPU_BMIPS5000) | |
86 | /* enable raceless SW interrupts */ | |
87 | set_c0_brcm_config(0x03 << 22); | |
88 | ||
89 | /* route HW interrupt 0 to CPU0, HW interrupt 1 to CPU1 */ | |
90 | change_c0_brcm_mode(0x1f << 27, 0x02 << 27); | |
91 | ||
92 | /* N cores, 2 threads per core */ | |
93 | max_cpus = (((read_c0_brcm_config() >> 6) & 0x03) + 1) << 1; | |
94 | ||
95 | /* clear any pending SW interrupts */ | |
96 | for (i = 0; i < max_cpus; i++) { | |
97 | write_c0_brcm_action(ACTION_CLR_IPI(i, 0)); | |
98 | write_c0_brcm_action(ACTION_CLR_IPI(i, 1)); | |
99 | } | |
100 | #endif | |
101 | ||
102 | if (!bmips_smp_enabled) | |
103 | max_cpus = 1; | |
104 | ||
105 | /* this can be overridden by the BSP */ | |
106 | if (!board_ebase_setup) | |
107 | board_ebase_setup = &bmips_ebase_setup; | |
108 | ||
109 | for (i = 0; i < max_cpus; i++) { | |
110 | __cpu_number_map[i] = 1; | |
111 | __cpu_logical_map[i] = 1; | |
112 | set_cpu_possible(i, 1); | |
113 | set_cpu_present(i, 1); | |
114 | } | |
115 | } | |
116 | ||
117 | /* | |
118 | * IPI IRQ setup - runs on CPU0 | |
119 | */ | |
120 | static void bmips_prepare_cpus(unsigned int max_cpus) | |
121 | { | |
122 | if (request_irq(IPI0_IRQ, bmips_ipi_interrupt, IRQF_PERCPU, | |
123 | "smp_ipi0", NULL)) | |
124 | panic("Can't request IPI0 interrupt\n"); | |
125 | if (request_irq(IPI1_IRQ, bmips_ipi_interrupt, IRQF_PERCPU, | |
126 | "smp_ipi1", NULL)) | |
127 | panic("Can't request IPI1 interrupt\n"); | |
128 | } | |
129 | ||
130 | /* | |
131 | * Tell the hardware to boot CPUx - runs on CPU0 | |
132 | */ | |
133 | static void bmips_boot_secondary(int cpu, struct task_struct *idle) | |
134 | { | |
135 | bmips_smp_boot_sp = __KSTK_TOS(idle); | |
136 | bmips_smp_boot_gp = (unsigned long)task_thread_info(idle); | |
137 | mb(); | |
138 | ||
139 | /* | |
140 | * Initial boot sequence for secondary CPU: | |
141 | * bmips_reset_nmi_vec @ a000_0000 -> | |
142 | * bmips_smp_entry -> | |
143 | * plat_wired_tlb_setup (cached function call; optional) -> | |
144 | * start_secondary (cached jump) | |
145 | * | |
146 | * Warm restart sequence: | |
147 | * play_dead WAIT loop -> | |
148 | * bmips_smp_int_vec @ BMIPS_WARM_RESTART_VEC -> | |
149 | * eret to play_dead -> | |
150 | * bmips_secondary_reentry -> | |
151 | * start_secondary | |
152 | */ | |
153 | ||
154 | pr_info("SMP: Booting CPU%d...\n", cpu); | |
155 | ||
156 | if (cpumask_test_cpu(cpu, &bmips_booted_mask)) | |
157 | bmips_send_ipi_single(cpu, 0); | |
158 | else { | |
159 | #if defined(CONFIG_CPU_BMIPS4350) || defined(CONFIG_CPU_BMIPS4380) | |
160 | set_c0_brcm_cmt_ctrl(0x01); | |
161 | #elif defined(CONFIG_CPU_BMIPS5000) | |
162 | if (cpu & 0x01) | |
163 | write_c0_brcm_action(ACTION_BOOT_THREAD(cpu)); | |
164 | else { | |
165 | /* | |
166 | * core N thread 0 was already booted; just | |
167 | * pulse the NMI line | |
168 | */ | |
169 | bmips_write_zscm_reg(0x210, 0xc0000000); | |
170 | udelay(10); | |
171 | bmips_write_zscm_reg(0x210, 0x00); | |
172 | } | |
173 | #endif | |
174 | cpumask_set_cpu(cpu, &bmips_booted_mask); | |
175 | } | |
176 | } | |
177 | ||
178 | /* | |
179 | * Early setup - runs on secondary CPU after cache probe | |
180 | */ | |
181 | static void bmips_init_secondary(void) | |
182 | { | |
183 | /* move NMI vector to kseg0, in case XKS01 is enabled */ | |
184 | ||
185 | #if defined(CONFIG_CPU_BMIPS4350) || defined(CONFIG_CPU_BMIPS4380) | |
186 | void __iomem *cbr = BMIPS_GET_CBR(); | |
187 | unsigned long old_vec; | |
188 | ||
189 | old_vec = __raw_readl(cbr + BMIPS_RELO_VECTOR_CONTROL_1); | |
190 | __raw_writel(old_vec & ~0x20000000, cbr + BMIPS_RELO_VECTOR_CONTROL_1); | |
191 | ||
192 | clear_c0_cause(smp_processor_id() ? C_SW1 : C_SW0); | |
193 | #elif defined(CONFIG_CPU_BMIPS5000) | |
194 | write_c0_brcm_bootvec(read_c0_brcm_bootvec() & | |
195 | (smp_processor_id() & 0x01 ? ~0x20000000 : ~0x2000)); | |
196 | ||
197 | write_c0_brcm_action(ACTION_CLR_IPI(smp_processor_id(), 0)); | |
198 | #endif | |
df0ac8a4 KC |
199 | } |
200 | ||
201 | /* | |
202 | * Late setup - runs on secondary CPU before entering the idle loop | |
203 | */ | |
204 | static void bmips_smp_finish(void) | |
205 | { | |
206 | pr_info("SMP: CPU%d is running\n", smp_processor_id()); | |
856ac3c6 YZ |
207 | |
208 | /* make sure there won't be a timer interrupt for a little while */ | |
209 | write_c0_compare(read_c0_count() + mips_hpt_frequency / HZ); | |
210 | ||
211 | irq_enable_hazard(); | |
212 | set_c0_status(IE_SW0 | IE_SW1 | IE_IRQ1 | IE_IRQ5 | ST0_IE); | |
213 | irq_enable_hazard(); | |
df0ac8a4 KC |
214 | } |
215 | ||
216 | /* | |
217 | * Runs on CPU0 after all CPUs have been booted | |
218 | */ | |
219 | static void bmips_cpus_done(void) | |
220 | { | |
221 | } | |
222 | ||
223 | #if defined(CONFIG_CPU_BMIPS5000) | |
224 | ||
225 | /* | |
226 | * BMIPS5000 raceless IPIs | |
227 | * | |
228 | * Each CPU has two inbound SW IRQs which are independent of all other CPUs. | |
229 | * IPI0 is used for SMP_RESCHEDULE_YOURSELF | |
230 | * IPI1 is used for SMP_CALL_FUNCTION | |
231 | */ | |
232 | ||
233 | static void bmips_send_ipi_single(int cpu, unsigned int action) | |
234 | { | |
235 | write_c0_brcm_action(ACTION_SET_IPI(cpu, action == SMP_CALL_FUNCTION)); | |
236 | } | |
237 | ||
238 | static irqreturn_t bmips_ipi_interrupt(int irq, void *dev_id) | |
239 | { | |
240 | int action = irq - IPI0_IRQ; | |
241 | ||
242 | write_c0_brcm_action(ACTION_CLR_IPI(smp_processor_id(), action)); | |
243 | ||
244 | if (action == 0) | |
245 | scheduler_ipi(); | |
246 | else | |
247 | smp_call_function_interrupt(); | |
248 | ||
249 | return IRQ_HANDLED; | |
250 | } | |
251 | ||
252 | #else | |
253 | ||
254 | /* | |
255 | * BMIPS43xx racey IPIs | |
256 | * | |
257 | * We use one inbound SW IRQ for each CPU. | |
258 | * | |
259 | * A spinlock must be held in order to keep CPUx from accidentally clearing | |
260 | * an incoming IPI when it writes CP0 CAUSE to raise an IPI on CPUy. The | |
261 | * same spinlock is used to protect the action masks. | |
262 | */ | |
263 | ||
264 | static DEFINE_SPINLOCK(ipi_lock); | |
265 | static DEFINE_PER_CPU(int, ipi_action_mask); | |
266 | ||
267 | static void bmips_send_ipi_single(int cpu, unsigned int action) | |
268 | { | |
269 | unsigned long flags; | |
270 | ||
271 | spin_lock_irqsave(&ipi_lock, flags); | |
272 | set_c0_cause(cpu ? C_SW1 : C_SW0); | |
273 | per_cpu(ipi_action_mask, cpu) |= action; | |
274 | irq_enable_hazard(); | |
275 | spin_unlock_irqrestore(&ipi_lock, flags); | |
276 | } | |
277 | ||
278 | static irqreturn_t bmips_ipi_interrupt(int irq, void *dev_id) | |
279 | { | |
280 | unsigned long flags; | |
281 | int action, cpu = irq - IPI0_IRQ; | |
282 | ||
283 | spin_lock_irqsave(&ipi_lock, flags); | |
284 | action = __get_cpu_var(ipi_action_mask); | |
285 | per_cpu(ipi_action_mask, cpu) = 0; | |
286 | clear_c0_cause(cpu ? C_SW1 : C_SW0); | |
287 | spin_unlock_irqrestore(&ipi_lock, flags); | |
288 | ||
289 | if (action & SMP_RESCHEDULE_YOURSELF) | |
290 | scheduler_ipi(); | |
291 | if (action & SMP_CALL_FUNCTION) | |
292 | smp_call_function_interrupt(); | |
293 | ||
294 | return IRQ_HANDLED; | |
295 | } | |
296 | ||
297 | #endif /* BMIPS type */ | |
298 | ||
299 | static void bmips_send_ipi_mask(const struct cpumask *mask, | |
300 | unsigned int action) | |
301 | { | |
302 | unsigned int i; | |
303 | ||
304 | for_each_cpu(i, mask) | |
305 | bmips_send_ipi_single(i, action); | |
306 | } | |
307 | ||
308 | #ifdef CONFIG_HOTPLUG_CPU | |
309 | ||
310 | static int bmips_cpu_disable(void) | |
311 | { | |
312 | unsigned int cpu = smp_processor_id(); | |
313 | ||
314 | if (cpu == 0) | |
315 | return -EBUSY; | |
316 | ||
317 | pr_info("SMP: CPU%d is offline\n", cpu); | |
318 | ||
0b5f9c00 | 319 | set_cpu_online(cpu, false); |
df0ac8a4 KC |
320 | cpu_clear(cpu, cpu_callin_map); |
321 | ||
322 | local_flush_tlb_all(); | |
323 | local_flush_icache_range(0, ~0); | |
324 | ||
325 | return 0; | |
326 | } | |
327 | ||
328 | static void bmips_cpu_die(unsigned int cpu) | |
329 | { | |
330 | } | |
331 | ||
332 | void __ref play_dead(void) | |
333 | { | |
334 | idle_task_exit(); | |
335 | ||
336 | /* flush data cache */ | |
337 | _dma_cache_wback_inv(0, ~0); | |
338 | ||
339 | /* | |
340 | * Wakeup is on SW0 or SW1; disable everything else | |
341 | * Use BEV !IV (BMIPS_WARM_RESTART_VEC) to avoid the regular Linux | |
342 | * IRQ handlers; this clears ST0_IE and returns immediately. | |
343 | */ | |
344 | clear_c0_cause(CAUSEF_IV | C_SW0 | C_SW1); | |
345 | change_c0_status(IE_IRQ5 | IE_IRQ1 | IE_SW0 | IE_SW1 | ST0_IE | ST0_BEV, | |
346 | IE_SW0 | IE_SW1 | ST0_IE | ST0_BEV); | |
347 | irq_disable_hazard(); | |
348 | ||
349 | /* | |
350 | * wait for SW interrupt from bmips_boot_secondary(), then jump | |
351 | * back to start_secondary() | |
352 | */ | |
353 | __asm__ __volatile__( | |
354 | " wait\n" | |
355 | " j bmips_secondary_reentry\n" | |
356 | : : : "memory"); | |
357 | } | |
358 | ||
359 | #endif /* CONFIG_HOTPLUG_CPU */ | |
360 | ||
361 | struct plat_smp_ops bmips_smp_ops = { | |
362 | .smp_setup = bmips_smp_setup, | |
363 | .prepare_cpus = bmips_prepare_cpus, | |
364 | .boot_secondary = bmips_boot_secondary, | |
365 | .smp_finish = bmips_smp_finish, | |
366 | .init_secondary = bmips_init_secondary, | |
367 | .cpus_done = bmips_cpus_done, | |
368 | .send_ipi_single = bmips_send_ipi_single, | |
369 | .send_ipi_mask = bmips_send_ipi_mask, | |
370 | #ifdef CONFIG_HOTPLUG_CPU | |
371 | .cpu_disable = bmips_cpu_disable, | |
372 | .cpu_die = bmips_cpu_die, | |
373 | #endif | |
374 | }; | |
375 | ||
376 | #endif /* CONFIG_SMP */ | |
377 | ||
378 | /*********************************************************************** | |
379 | * BMIPS vector relocation | |
380 | * This is primarily used for SMP boot, but it is applicable to some | |
381 | * UP BMIPS systems as well. | |
382 | ***********************************************************************/ | |
383 | ||
384 | static void __cpuinit bmips_wr_vec(unsigned long dst, char *start, char *end) | |
385 | { | |
386 | memcpy((void *)dst, start, end - start); | |
387 | dma_cache_wback((unsigned long)start, end - start); | |
388 | local_flush_icache_range(dst, dst + (end - start)); | |
389 | instruction_hazard(); | |
390 | } | |
391 | ||
392 | static inline void __cpuinit bmips_nmi_handler_setup(void) | |
393 | { | |
394 | bmips_wr_vec(BMIPS_NMI_RESET_VEC, &bmips_reset_nmi_vec, | |
395 | &bmips_reset_nmi_vec_end); | |
396 | bmips_wr_vec(BMIPS_WARM_RESTART_VEC, &bmips_smp_int_vec, | |
397 | &bmips_smp_int_vec_end); | |
398 | } | |
399 | ||
400 | void __cpuinit bmips_ebase_setup(void) | |
401 | { | |
402 | unsigned long new_ebase = ebase; | |
403 | void __iomem __maybe_unused *cbr; | |
404 | ||
405 | BUG_ON(ebase != CKSEG0); | |
406 | ||
407 | #if defined(CONFIG_CPU_BMIPS4350) | |
408 | /* | |
409 | * BMIPS4350 cannot relocate the normal vectors, but it | |
410 | * can relocate the BEV=1 vectors. So CPU1 starts up at | |
411 | * the relocated BEV=1, IV=0 general exception vector @ | |
412 | * 0xa000_0380. | |
413 | * | |
414 | * set_uncached_handler() is used here because: | |
415 | * - CPU1 will run this from uncached space | |
416 | * - None of the cacheflush functions are set up yet | |
417 | */ | |
418 | set_uncached_handler(BMIPS_WARM_RESTART_VEC - CKSEG0, | |
419 | &bmips_smp_int_vec, 0x80); | |
420 | __sync(); | |
421 | return; | |
422 | #elif defined(CONFIG_CPU_BMIPS4380) | |
423 | /* | |
424 | * 0x8000_0000: reset/NMI (initially in kseg1) | |
425 | * 0x8000_0400: normal vectors | |
426 | */ | |
427 | new_ebase = 0x80000400; | |
428 | cbr = BMIPS_GET_CBR(); | |
429 | __raw_writel(0x80080800, cbr + BMIPS_RELO_VECTOR_CONTROL_0); | |
430 | __raw_writel(0xa0080800, cbr + BMIPS_RELO_VECTOR_CONTROL_1); | |
431 | #elif defined(CONFIG_CPU_BMIPS5000) | |
432 | /* | |
433 | * 0x8000_0000: reset/NMI (initially in kseg1) | |
434 | * 0x8000_1000: normal vectors | |
435 | */ | |
436 | new_ebase = 0x80001000; | |
437 | write_c0_brcm_bootvec(0xa0088008); | |
438 | write_c0_ebase(new_ebase); | |
439 | if (max_cpus > 2) | |
440 | bmips_write_zscm_reg(0xa0, 0xa008a008); | |
441 | #else | |
442 | return; | |
443 | #endif | |
444 | board_nmi_handler_setup = &bmips_nmi_handler_setup; | |
445 | ebase = new_ebase; | |
446 | } | |
447 | ||
448 | asmlinkage void __weak plat_wired_tlb_setup(void) | |
449 | { | |
450 | /* | |
451 | * Called when starting/restarting a secondary CPU. | |
452 | * Kernel stacks and other important data might only be accessible | |
453 | * once the wired entries are present. | |
454 | */ | |
455 | } |