1/*
2 * ip28-berr.c: Bus error handling.
3 *
4 * Copyright (C) 2002, 2003 Ladislav Michl (ladis@linux-mips.org)
5 * Copyright (C) 2005 Peter Fuerst (pf@net.alphadv.de) - IP28
6 */
7
8#include <linux/init.h>
9#include <linux/kernel.h>
10#include <linux/sched.h>
11#include <linux/seq_file.h>
12
13#include <asm/addrspace.h>
14#include <asm/traps.h>
15#include <asm/branch.h>
16#include <asm/irq_regs.h>
17#include <asm/sgi/mc.h>
18#include <asm/sgi/hpc3.h>
19#include <asm/sgi/ioc.h>
20#include <asm/sgi/ip22.h>
21#include <asm/r4kcache.h>
22#include <asm/uaccess.h>
23#include <asm/bootinfo.h>
24
25static unsigned int count_be_is_fixup;
26static unsigned int count_be_handler;
27static unsigned int count_be_interrupt;
28static int debug_be_interrupt;
29
30static unsigned int cpu_err_stat;	/* Status reg for CPU */
31static unsigned int gio_err_stat;	/* Status reg for GIO */
32static unsigned int cpu_err_addr;	/* Error address reg for CPU */
33static unsigned int gio_err_addr;	/* Error address reg for GIO */
34static unsigned int extio_stat;
35static unsigned int hpc3_berr_stat;	/* Bus error interrupt status */
36
37struct hpc3_stat {
38	unsigned long addr;
39	unsigned int ctrl;
40	unsigned int cbp;
41	unsigned int ndptr;
42};
43
44static struct {
45	struct hpc3_stat pbdma[8];
46	struct hpc3_stat scsi[2];
47	struct hpc3_stat ethrx, ethtx;
48} hpc3;
49
50static struct {
51	unsigned long err_addr;
52	struct {
53		u32 lo;
54		u32 hi;
55	} tags[1][2], tagd[4][2], tagi[4][2]; /* Way 0/1 */
56} cache_tags;
57
58static inline void save_cache_tags(unsigned busaddr)
59{
60	unsigned long addr = CAC_BASE | busaddr;
61	int i;
62	cache_tags.err_addr = addr;
63
64	/*
65	 * Starting with a bus-address, save secondary cache (indexed by
66	 * PA[23..18:7..6]) tags first.
67	 */
68	addr &= ~1L;
69#define tag cache_tags.tags[0]
70	cache_op(Index_Load_Tag_S, addr);
71	tag[0].lo = read_c0_taglo();	/* PA[35:18], VA[13:12] */
72	tag[0].hi = read_c0_taghi();	/* PA[39:36] */
73	cache_op(Index_Load_Tag_S, addr | 1L);
74	tag[1].lo = read_c0_taglo();	/* PA[35:18], VA[13:12] */
75	tag[1].hi = read_c0_taghi();	/* PA[39:36] */
76#undef tag
77
78	/*
79	 * Save all primary data cache (indexed by VA[13:5]) tags which
80	 * might fit to this bus-address, knowing that VA[11:0] == PA[11:0].
81	 * Saving all tags and evaluating them later is easier and safer
82	 * than relying on VA[13:12] from the secondary cache tags to pick
83	 * matching primary tags here already.
84	 */
85	addr &= (0xffL << 56) | ((1 << 12) - 1);
86#define tag cache_tags.tagd[i]
87	for (i = 0; i < 4; ++i, addr += (1 << 12)) {
88		cache_op(Index_Load_Tag_D, addr);
89		tag[0].lo = read_c0_taglo();	/* PA[35:12] */
90		tag[0].hi = read_c0_taghi();	/* PA[39:36] */
91		cache_op(Index_Load_Tag_D, addr | 1L);
92		tag[1].lo = read_c0_taglo();	/* PA[35:12] */
93		tag[1].hi = read_c0_taghi();	/* PA[39:36] */
94	}
95#undef tag
96
97	/*
98	 * Save primary instruction cache (indexed by VA[13:6]) tags
99	 * the same way.
100	 */
101	addr &= (0xffL << 56) | ((1 << 12) - 1);
102#define tag cache_tags.tagi[i]
103	for (i = 0; i < 4; ++i, addr += (1 << 12)) {
104		cache_op(Index_Load_Tag_I, addr);
105		tag[0].lo = read_c0_taglo();	/* PA[35:12] */
106		tag[0].hi = read_c0_taghi();	/* PA[39:36] */
107		cache_op(Index_Load_Tag_I, addr | 1L);
108		tag[1].lo = read_c0_taglo();	/* PA[35:12] */
109		tag[1].hi = read_c0_taghi();	/* PA[39:36] */
110	}
111#undef tag
112}
113
114#define GIO_ERRMASK	0xff00
115#define CPU_ERRMASK	0x3f00
116
117static void save_and_clear_buserr(void)
118{
119	int i;
120
121	/* save status registers */
122	cpu_err_addr = sgimc->cerr;
123	cpu_err_stat = sgimc->cstat;
124	gio_err_addr = sgimc->gerr;
125	gio_err_stat = sgimc->gstat;
126	extio_stat = sgioc->extio;
127	hpc3_berr_stat = hpc3c0->bestat;
128
129	hpc3.scsi[0].addr  = (unsigned long)&hpc3c0->scsi_chan0;
130	hpc3.scsi[0].ctrl  = hpc3c0->scsi_chan0.ctrl; /* HPC3_SCTRL_ACTIVE ? */
131	hpc3.scsi[0].cbp   = hpc3c0->scsi_chan0.cbptr;
132	hpc3.scsi[0].ndptr = hpc3c0->scsi_chan0.ndptr;
133
134	hpc3.scsi[1].addr  = (unsigned long)&hpc3c0->scsi_chan1;
135	hpc3.scsi[1].ctrl  = hpc3c0->scsi_chan1.ctrl; /* HPC3_SCTRL_ACTIVE ? */
136	hpc3.scsi[1].cbp   = hpc3c0->scsi_chan1.cbptr;
137	hpc3.scsi[1].ndptr = hpc3c0->scsi_chan1.ndptr;
138
139	hpc3.ethrx.addr	 = (unsigned long)&hpc3c0->ethregs.rx_cbptr;
140	hpc3.ethrx.ctrl	 = hpc3c0->ethregs.rx_ctrl; /* HPC3_ERXCTRL_ACTIVE ? */
141	hpc3.ethrx.cbp	 = hpc3c0->ethregs.rx_cbptr;
142	hpc3.ethrx.ndptr = hpc3c0->ethregs.rx_ndptr;
143
144	hpc3.ethtx.addr	 = (unsigned long)&hpc3c0->ethregs.tx_cbptr;
145	hpc3.ethtx.ctrl	 = hpc3c0->ethregs.tx_ctrl; /* HPC3_ETXCTRL_ACTIVE ? */
146	hpc3.ethtx.cbp	 = hpc3c0->ethregs.tx_cbptr;
147	hpc3.ethtx.ndptr = hpc3c0->ethregs.tx_ndptr;
148
149	for (i = 0; i < 8; ++i) {
150		/* HPC3_PDMACTRL_ISACT ? */
151		hpc3.pbdma[i].addr  = (unsigned long)&hpc3c0->pbdma[i];
152		hpc3.pbdma[i].ctrl  = hpc3c0->pbdma[i].pbdma_ctrl;
153		hpc3.pbdma[i].cbp   = hpc3c0->pbdma[i].pbdma_bptr;
154		hpc3.pbdma[i].ndptr = hpc3c0->pbdma[i].pbdma_dptr;
155	}
156	i = 0;
157	if (gio_err_stat & CPU_ERRMASK)
158		i = gio_err_addr;
159	if (cpu_err_stat & CPU_ERRMASK)
160		i = cpu_err_addr;
161	save_cache_tags(i);
162
163	sgimc->cstat = sgimc->gstat = 0;
164}
165
166static void print_cache_tags(void)
167{
168	u32 scb, scw;
169	int i;
170
171	printk(KERN_ERR "Cache tags @ %08x:\n", (unsigned)cache_tags.err_addr);
172
173	/* PA[31:12] shifted to PTag0 (PA[35:12]) format */
174	scw = (cache_tags.err_addr >> 4) & 0x0fffff00;
175
176	scb = cache_tags.err_addr & ((1 << 12) - 1) & ~((1 << 5) - 1);
177	for (i = 0; i < 4; ++i) { /* for each possible VA[13:12] value */
178		if ((cache_tags.tagd[i][0].lo & 0x0fffff00) != scw &&
179		    (cache_tags.tagd[i][1].lo & 0x0fffff00) != scw)
180		    continue;
181		printk(KERN_ERR
182		       "D: 0: %08x %08x, 1: %08x %08x  (VA[13:5]  %04x)\n",
183			cache_tags.tagd[i][0].hi, cache_tags.tagd[i][0].lo,
184			cache_tags.tagd[i][1].hi, cache_tags.tagd[i][1].lo,
185			scb | (1 << 12)*i);
186	}
187	scb = cache_tags.err_addr & ((1 << 12) - 1) & ~((1 << 6) - 1);
188	for (i = 0; i < 4; ++i) { /* for each possible VA[13:12] value */
189		if ((cache_tags.tagi[i][0].lo & 0x0fffff00) != scw &&
190		    (cache_tags.tagi[i][1].lo & 0x0fffff00) != scw)
191		    continue;
192		printk(KERN_ERR
193		       "I: 0: %08x %08x, 1: %08x %08x  (VA[13:6]  %04x)\n",
194			cache_tags.tagi[i][0].hi, cache_tags.tagi[i][0].lo,
195			cache_tags.tagi[i][1].hi, cache_tags.tagi[i][1].lo,
196			scb | (1 << 12)*i);
197	}
198	i = read_c0_config();
199	scb = i & (1 << 13) ? 7:6;	/* scblksize = 2^[7..6] */
200	scw = ((i >> 16) & 7) + 19 - 1; /* scwaysize = 2^[24..19] / 2 */
201
202	i = ((1 << scw) - 1) & ~((1 << scb) - 1);
203	printk(KERN_ERR "S: 0: %08x %08x, 1: %08x %08x	(PA[%u:%u] %05x)\n",
204		cache_tags.tags[0][0].hi, cache_tags.tags[0][0].lo,
205		cache_tags.tags[0][1].hi, cache_tags.tags[0][1].lo,
206		scw-1, scb, i & (unsigned)cache_tags.err_addr);
207}
208
209static inline const char *cause_excode_text(int cause)
210{
211	static const char *txt[32] =
212	{	"Interrupt",
213		"TLB modification",
214		"TLB (load or instruction fetch)",
215		"TLB (store)",
216		"Address error (load or instruction fetch)",
217		"Address error (store)",
218		"Bus error (instruction fetch)",
219		"Bus error (data: load or store)",
220		"Syscall",
221		"Breakpoint",
222		"Reserved instruction",
223		"Coprocessor unusable",
224		"Arithmetic Overflow",
225		"Trap",
226		"14",
227		"Floating-Point",
228		"16", "17", "18", "19", "20", "21", "22",
229		"Watch Hi/Lo",
230		"24", "25", "26", "27", "28", "29", "30", "31",
231	};
232	return txt[(cause & 0x7c) >> 2];
233}
234
235static void print_buserr(const struct pt_regs *regs)
236{
237	const int field = 2 * sizeof(unsigned long);
238	int error = 0;
239
240	if (extio_stat & EXTIO_MC_BUSERR) {
241		printk(KERN_ERR "MC Bus Error\n");
242		error |= 1;
243	}
244	if (extio_stat & EXTIO_HPC3_BUSERR) {
245		printk(KERN_ERR "HPC3 Bus Error 0x%x:<id=0x%x,%s,lane=0x%x>\n",
246			hpc3_berr_stat,
247			(hpc3_berr_stat & HPC3_BESTAT_PIDMASK) >>
248					  HPC3_BESTAT_PIDSHIFT,
249			(hpc3_berr_stat & HPC3_BESTAT_CTYPE) ? "PIO" : "DMA",
250			hpc3_berr_stat & HPC3_BESTAT_BLMASK);
251		error |= 2;
252	}
253	if (extio_stat & EXTIO_EISA_BUSERR) {
254		printk(KERN_ERR "EISA Bus Error\n");
255		error |= 4;
256	}
257	if (cpu_err_stat & CPU_ERRMASK) {
258		printk(KERN_ERR "CPU error 0x%x<%s%s%s%s%s%s> @ 0x%08x\n",
259			cpu_err_stat,
260			cpu_err_stat & SGIMC_CSTAT_RD ? "RD " : "",
261			cpu_err_stat & SGIMC_CSTAT_PAR ? "PAR " : "",
262			cpu_err_stat & SGIMC_CSTAT_ADDR ? "ADDR " : "",
263			cpu_err_stat & SGIMC_CSTAT_SYSAD_PAR ? "SYSAD " : "",
264			cpu_err_stat & SGIMC_CSTAT_SYSCMD_PAR ? "SYSCMD " : "",
265			cpu_err_stat & SGIMC_CSTAT_BAD_DATA ? "BAD_DATA " : "",
266			cpu_err_addr);
267		error |= 8;
268	}
269	if (gio_err_stat & GIO_ERRMASK) {
270		printk(KERN_ERR "GIO error 0x%x:<%s%s%s%s%s%s%s%s> @ 0x%08x\n",
271			gio_err_stat,
272			gio_err_stat & SGIMC_GSTAT_RD ? "RD " : "",
273			gio_err_stat & SGIMC_GSTAT_WR ? "WR " : "",
274			gio_err_stat & SGIMC_GSTAT_TIME ? "TIME " : "",
275			gio_err_stat & SGIMC_GSTAT_PROM ? "PROM " : "",
276			gio_err_stat & SGIMC_GSTAT_ADDR ? "ADDR " : "",
277			gio_err_stat & SGIMC_GSTAT_BC ? "BC " : "",
278			gio_err_stat & SGIMC_GSTAT_PIO_RD ? "PIO_RD " : "",
279			gio_err_stat & SGIMC_GSTAT_PIO_WR ? "PIO_WR " : "",
280			gio_err_addr);
281		error |= 16;
282	}
283	if (!error)
284		printk(KERN_ERR "MC: Hmm, didn't find any error condition.\n");
285	else {
286		printk(KERN_ERR "CP0: config %08x,  "
287			"MC: cpuctrl0/1: %08x/%05x, giopar: %04x\n"
288			"MC: cpu/gio_memacc: %08x/%05x, memcfg0/1: %08x/%08x\n",
289			read_c0_config(),
290			sgimc->cpuctrl0, sgimc->cpuctrl0, sgimc->giopar,
291			sgimc->cmacc, sgimc->gmacc,
292			sgimc->mconfig0, sgimc->mconfig1);
293		print_cache_tags();
294	}
295	printk(KERN_ALERT "%s, epc == %0*lx, ra == %0*lx\n",
296	       cause_excode_text(regs->cp0_cause),
297	       field, regs->cp0_epc, field, regs->regs[31]);
298}
299
300/*
301 * Check, whether MC's (virtual) DMA address caused the bus error.
302 * See "Virtual DMA Specification", Draft 1.5, Feb 13 1992, SGI
303 */
304
305static int addr_is_ram(unsigned long addr, unsigned sz)
306{
307	int i;
308
309	for (i = 0; i < boot_mem_map.nr_map; i++) {
310		unsigned long a = boot_mem_map.map[i].addr;
311		if (a <= addr && addr+sz <= a+boot_mem_map.map[i].size)
312			return 1;
313	}
314	return 0;
315}
316
317static int check_microtlb(u32 hi, u32 lo, unsigned long vaddr)
318{
319	/* This is likely rather similar to correct code ;-) */
320
321	vaddr &= 0x7fffffff; /* Doc. states that top bit is ignored */
322
323	/* If tlb-entry is valid and VPN-high (bits [30:21] ?) matches... */
324	if ((lo & 2) && (vaddr >> 21) == ((hi<<1) >> 22)) {
325		u32 ctl = sgimc->dma_ctrl;
326		if (ctl & 1) {
327			unsigned int pgsz = (ctl & 2) ? 14:12; /* 16k:4k */
328			/* PTEIndex is VPN-low (bits [22:14]/[20:12] ?) */
329			unsigned long pte = (lo >> 6) << 12; /* PTEBase */
330			pte += 8*((vaddr >> pgsz) & 0x1ff);
331			if (addr_is_ram(pte, 8)) {
332				/*
333				 * Note: Since DMA hardware does look up
334				 * translation on its own, this PTE *must*
335				 * match the TLB/EntryLo-register format !
336				 */
337				unsigned long a = *(unsigned long *)
338						PHYS_TO_XKSEG_UNCACHED(pte);
339				a = (a & 0x3f) << 6; /* PFN */
340				a += vaddr & ((1 << pgsz) - 1);
341				return (cpu_err_addr == a);
342			}
343		}
344	}
345	return 0;
346}
347
348static int check_vdma_memaddr(void)
349{
350	if (cpu_err_stat & CPU_ERRMASK) {
351		u32 a = sgimc->maddronly;
352
353		if (!(sgimc->dma_ctrl & 0x100)) /* Xlate-bit clear ? */
354			return (cpu_err_addr == a);
355
356		if (check_microtlb(sgimc->dtlb_hi0, sgimc->dtlb_lo0, a) ||
357		    check_microtlb(sgimc->dtlb_hi1, sgimc->dtlb_lo1, a) ||
358		    check_microtlb(sgimc->dtlb_hi2, sgimc->dtlb_lo2, a) ||
359		    check_microtlb(sgimc->dtlb_hi3, sgimc->dtlb_lo3, a))
360			return 1;
361	}
362	return 0;
363}
364
365static int check_vdma_gioaddr(void)
366{
367	if (gio_err_stat & GIO_ERRMASK) {
368		u32 a = sgimc->gio_dma_trans;
369		a = (sgimc->gmaddronly & ~a) | (sgimc->gio_dma_sbits & a);
370		return (gio_err_addr == a);
371	}
372	return 0;
373}
374
375/*
376 * MC sends an interrupt whenever bus or parity errors occur. In addition,
377 * if the error happened during a CPU read, it also asserts the bus error
378 * pin on the R4K. Code in bus error handler save the MC bus error registers
379 * and then clear the interrupt when this happens.
380 */
381
382static int ip28_be_interrupt(const struct pt_regs *regs)
383{
384	int i;
385
386	save_and_clear_buserr();
387	/*
388	 * Try to find out, whether we got here by a mispredicted speculative
389	 * load/store operation.  If so, it's not fatal, we can go on.
390	 */
391	/* Any cause other than "Interrupt" (ExcCode 0) is fatal. */
392	if (regs->cp0_cause & CAUSEF_EXCCODE)
393		goto mips_be_fatal;
394
395	/* Any cause other than "Bus error interrupt" (IP6) is weird. */
396	if ((regs->cp0_cause & CAUSEF_IP6) != CAUSEF_IP6)
397		goto mips_be_fatal;
398
399	if (extio_stat & (EXTIO_HPC3_BUSERR | EXTIO_EISA_BUSERR))
400		goto mips_be_fatal;
401
402	/* Any state other than "Memory bus error" is fatal. */
403	if (cpu_err_stat & CPU_ERRMASK & ~SGIMC_CSTAT_ADDR)
404		goto mips_be_fatal;
405
406	/* GIO errors other than timeouts are fatal */
407	if (gio_err_stat & GIO_ERRMASK & ~SGIMC_GSTAT_TIME)
408		goto mips_be_fatal;
409
410	/*
411	 * Now we have an asynchronous bus error, speculatively or DMA caused.
412	 * Need to search all DMA descriptors for the error address.
413	 */
414	for (i = 0; i < sizeof(hpc3)/sizeof(struct hpc3_stat); ++i) {
415		struct hpc3_stat *hp = (struct hpc3_stat *)&hpc3 + i;
416		if ((cpu_err_stat & CPU_ERRMASK) &&
417		    (cpu_err_addr == hp->ndptr || cpu_err_addr == hp->cbp))
418			break;
419		if ((gio_err_stat & GIO_ERRMASK) &&
420		    (gio_err_addr == hp->ndptr || gio_err_addr == hp->cbp))
421			break;
422	}
423	if (i < sizeof(hpc3)/sizeof(struct hpc3_stat)) {
424		struct hpc3_stat *hp = (struct hpc3_stat *)&hpc3 + i;
425		printk(KERN_ERR "at DMA addresses: HPC3 @ %08lx:"
426		       " ctl %08x, ndp %08x, cbp %08x\n",
427		       CPHYSADDR(hp->addr), hp->ctrl, hp->ndptr, hp->cbp);
428		goto mips_be_fatal;
429	}
430	/* Check MC's virtual DMA stuff. */
431	if (check_vdma_memaddr()) {
432		printk(KERN_ERR "at GIO DMA: mem address 0x%08x.\n",
433			sgimc->maddronly);
434		goto mips_be_fatal;
435	}
436	if (check_vdma_gioaddr()) {
437		printk(KERN_ERR "at GIO DMA: gio address 0x%08x.\n",
438			sgimc->gmaddronly);
439		goto mips_be_fatal;
440	}
441	/* A speculative bus error... */
442	if (debug_be_interrupt) {
443		print_buserr(regs);
444		printk(KERN_ERR "discarded!\n");
445	}
446	return MIPS_BE_DISCARD;
447
448mips_be_fatal:
449	print_buserr(regs);
450	return MIPS_BE_FATAL;
451}
452
453void ip22_be_interrupt(int irq)
454{
455	struct pt_regs *regs = get_irq_regs();
456
457	count_be_interrupt++;
458
459	if (ip28_be_interrupt(regs) != MIPS_BE_DISCARD) {
460		/* Assume it would be too dangerous to continue ... */
461		die_if_kernel("Oops", regs);
462		force_sig(SIGBUS, current);
463	} else if (debug_be_interrupt)
464		show_regs((struct pt_regs *)regs);
465}
466
467static int ip28_be_handler(struct pt_regs *regs, int is_fixup)
468{
469	/*
470	 * We arrive here only in the unusual case of do_be() invocation,
471	 * i.e. by a bus error exception without a bus error interrupt.
472	 */
473	if (is_fixup) {
474		count_be_is_fixup++;
475		save_and_clear_buserr();
476		return MIPS_BE_FIXUP;
477	}
478	count_be_handler++;
479	return ip28_be_interrupt(regs);
480}
481
482void __init ip22_be_init(void)
483{
484	board_be_handler = ip28_be_handler;
485}
486
487int ip28_show_be_info(struct seq_file *m)
488{
489	seq_printf(m, "IP28 be fixups\t\t: %u\n", count_be_is_fixup);
490	seq_printf(m, "IP28 be interrupts\t: %u\n", count_be_interrupt);
491	seq_printf(m, "IP28 be handler\t\t: %u\n", count_be_handler);
492
493	return 0;
494}
495
496static int __init debug_be_setup(char *str)
497{
498	debug_be_interrupt++;
499	return 1;
500}
501__setup("ip28_debug_be", debug_be_setup);
502