Free Electrons

Embedded Linux Experts

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
#include <linux/kernel.h>
#include <linux/serial.h>
#include <linux/serial_8250.h>
#include <linux/serial_core.h>
#include <linux/console.h>
#include <linux/pci.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/serial_reg.h>
#include <asm/io.h>
#include <asm/mmu.h>
#include <asm/prom.h>
#include <asm/serial.h>
#include <asm/udbg.h>
#include <asm/pci-bridge.h>
#include <asm/ppc-pci.h>

#undef DEBUG

#ifdef DEBUG
#define DBG(fmt...) do { printk(fmt); } while(0)
#else
#define DBG(fmt...) do { } while(0)
#endif

#define MAX_LEGACY_SERIAL_PORTS	8

static struct plat_serial8250_port
legacy_serial_ports[MAX_LEGACY_SERIAL_PORTS+1];
static struct legacy_serial_info {
	struct device_node		*np;
	unsigned int			speed;
	unsigned int			clock;
	int				irq_check_parent;
	phys_addr_t			taddr;
} legacy_serial_infos[MAX_LEGACY_SERIAL_PORTS];

static const struct of_device_id legacy_serial_parents[] __initconst = {
	{.type = "soc",},
	{.type = "tsi-bridge",},
	{.type = "opb", },
	{.compatible = "ibm,opb",},
	{.compatible = "simple-bus",},
	{.compatible = "wrs,epld-localbus",},
	{},
};

static unsigned int legacy_serial_count;
static int legacy_serial_console = -1;

static const upf_t legacy_port_flags = UPF_BOOT_AUTOCONF | UPF_SKIP_TEST |
	UPF_SHARE_IRQ | UPF_FIXED_PORT;

static unsigned int tsi_serial_in(struct uart_port *p, int offset)
{
	unsigned int tmp;
	offset = offset << p->regshift;
	if (offset == UART_IIR) {
		tmp = readl(p->membase + (UART_IIR & ~3));
		return (tmp >> 16) & 0xff; /* UART_IIR % 4 == 2 */
	} else
		return readb(p->membase + offset);
}

static void tsi_serial_out(struct uart_port *p, int offset, int value)
{
	offset = offset << p->regshift;
	if (!((offset == UART_IER) && (value & UART_IER_UUE)))
		writeb(value, p->membase + offset);
}

static int __init add_legacy_port(struct device_node *np, int want_index,
				  int iotype, phys_addr_t base,
				  phys_addr_t taddr, unsigned long irq,
				  upf_t flags, int irq_check_parent)
{
	const __be32 *clk, *spd, *rs;
	u32 clock = BASE_BAUD * 16;
	u32 shift = 0;
	int index;

	/* get clock freq. if present */
	clk = of_get_property(np, "clock-frequency", NULL);
	if (clk && *clk)
		clock = be32_to_cpup(clk);

	/* get default speed if present */
	spd = of_get_property(np, "current-speed", NULL);

	/* get register shift if present */
	rs = of_get_property(np, "reg-shift", NULL);
	if (rs && *rs)
		shift = be32_to_cpup(rs);

	/* If we have a location index, then try to use it */
	if (want_index >= 0 && want_index < MAX_LEGACY_SERIAL_PORTS)
		index = want_index;
	else
		index = legacy_serial_count;

	/* if our index is still out of range, that mean that
	 * array is full, we could scan for a free slot but that
	 * make little sense to bother, just skip the port
	 */
	if (index >= MAX_LEGACY_SERIAL_PORTS)
		return -1;
	if (index >= legacy_serial_count)
		legacy_serial_count = index + 1;

	/* Check if there is a port who already claimed our slot */
	if (legacy_serial_infos[index].np != NULL) {
		/* if we still have some room, move it, else override */
		if (legacy_serial_count < MAX_LEGACY_SERIAL_PORTS) {
			printk(KERN_DEBUG "Moved legacy port %d -> %d\n",
			       index, legacy_serial_count);
			legacy_serial_ports[legacy_serial_count] =
				legacy_serial_ports[index];
			legacy_serial_infos[legacy_serial_count] =
				legacy_serial_infos[index];
			legacy_serial_count++;
		} else {
			printk(KERN_DEBUG "Replacing legacy port %d\n", index);
		}
	}

	/* Now fill the entry */
	memset(&legacy_serial_ports[index], 0,
	       sizeof(struct plat_serial8250_port));
	if (iotype == UPIO_PORT)
		legacy_serial_ports[index].iobase = base;
	else
		legacy_serial_ports[index].mapbase = base;

	legacy_serial_ports[index].iotype = iotype;
	legacy_serial_ports[index].uartclk = clock;
	legacy_serial_ports[index].irq = irq;
	legacy_serial_ports[index].flags = flags;
	legacy_serial_ports[index].regshift = shift;
	legacy_serial_infos[index].taddr = taddr;
	legacy_serial_infos[index].np = of_node_get(np);
	legacy_serial_infos[index].clock = clock;
	legacy_serial_infos[index].speed = spd ? be32_to_cpup(spd) : 0;
	legacy_serial_infos[index].irq_check_parent = irq_check_parent;

	if (iotype == UPIO_TSI) {
		legacy_serial_ports[index].serial_in = tsi_serial_in;
		legacy_serial_ports[index].serial_out = tsi_serial_out;
	}

	printk(KERN_DEBUG "Found legacy serial port %d for %s\n",
	       index, np->full_name);
	printk(KERN_DEBUG "  %s=%llx, taddr=%llx, irq=%lx, clk=%d, speed=%d\n",
	       (iotype == UPIO_PORT) ? "port" : "mem",
	       (unsigned long long)base, (unsigned long long)taddr, irq,
	       legacy_serial_ports[index].uartclk,
	       legacy_serial_infos[index].speed);

	return index;
}

static int __init add_legacy_soc_port(struct device_node *np,
				      struct device_node *soc_dev)
{
	u64 addr;
	const __be32 *addrp;
	struct device_node *tsi = of_get_parent(np);

	/* We only support ports that have a clock frequency properly
	 * encoded in the device-tree.
	 */
	if (of_get_property(np, "clock-frequency", NULL) == NULL)
		return -1;

	/* if reg-offset don't try to use it */
	if ((of_get_property(np, "reg-offset", NULL) != NULL))
		return -1;

	/* if rtas uses this device, don't try to use it as well */
	if (of_get_property(np, "used-by-rtas", NULL) != NULL)
		return -1;

	/* Get the address */
	addrp = of_get_address(soc_dev, 0, NULL, NULL);
	if (addrp == NULL)
		return -1;

	addr = of_translate_address(soc_dev, addrp);
	if (addr == OF_BAD_ADDR)
		return -1;

	/* Add port, irq will be dealt with later. We passed a translated
	 * IO port value. It will be fixed up later along with the irq
	 */
	if (tsi && !strcmp(tsi->type, "tsi-bridge"))
		return add_legacy_port(np, -1, UPIO_TSI, addr, addr,
				       0, legacy_port_flags, 0);
	else
		return add_legacy_port(np, -1, UPIO_MEM, addr, addr,
				       0, legacy_port_flags, 0);
}

static int __init add_legacy_isa_port(struct device_node *np,
				      struct device_node *isa_brg)
{
	const __be32 *reg;
	const char *typep;
	int index = -1;
	u64 taddr;

	DBG(" -> add_legacy_isa_port(%s)\n", np->full_name);

	/* Get the ISA port number */
	reg = of_get_property(np, "reg", NULL);
	if (reg == NULL)
		return -1;

	/* Verify it's an IO port, we don't support anything else */
	if (!(be32_to_cpu(reg[0]) & 0x00000001))
		return -1;

	/* Now look for an "ibm,aix-loc" property that gives us ordering
	 * if any...
	 */
	typep = of_get_property(np, "ibm,aix-loc", NULL);

	/* If we have a location index, then use it */
	if (typep && *typep == 'S')
		index = simple_strtol(typep+1, NULL, 0) - 1;

	/* Translate ISA address. If it fails, we still register the port
	 * with no translated address so that it can be picked up as an IO
	 * port later by the serial driver
	 *
	 * Note: Don't even try on P8 lpc, we know it's not directly mapped
	 */
	if (!of_device_is_compatible(isa_brg, "ibm,power8-lpc") ||
	    of_get_property(isa_brg, "ranges", NULL)) {
		taddr = of_translate_address(np, reg);
		if (taddr == OF_BAD_ADDR)
			taddr = 0;
	} else
		taddr = 0;

	/* Add port, irq will be dealt with later */
	return add_legacy_port(np, index, UPIO_PORT, be32_to_cpu(reg[1]),
			       taddr, 0, legacy_port_flags, 0);

}

#ifdef CONFIG_PCI
static int __init add_legacy_pci_port(struct device_node *np,
				      struct device_node *pci_dev)
{
	u64 addr, base;
	const __be32 *addrp;
	unsigned int flags;
	int iotype, index = -1, lindex = 0;

	DBG(" -> add_legacy_pci_port(%s)\n", np->full_name);

	/* We only support ports that have a clock frequency properly
	 * encoded in the device-tree (that is have an fcode). Anything
	 * else can't be used that early and will be normally probed by
	 * the generic 8250_pci driver later on. The reason is that 8250
	 * compatible UARTs on PCI need all sort of quirks (port offsets
	 * etc...) that this code doesn't know about
	 */
	if (of_get_property(np, "clock-frequency", NULL) == NULL)
		return -1;

	/* Get the PCI address. Assume BAR 0 */
	addrp = of_get_pci_address(pci_dev, 0, NULL, &flags);
	if (addrp == NULL)
		return -1;

	/* We only support BAR 0 for now */
	iotype = (flags & IORESOURCE_MEM) ? UPIO_MEM : UPIO_PORT;
	addr = of_translate_address(pci_dev, addrp);
	if (addr == OF_BAD_ADDR)
		return -1;

	/* Set the IO base to the same as the translated address for MMIO,
	 * or to the domain local IO base for PIO (it will be fixed up later)
	 */
	if (iotype == UPIO_MEM)
		base = addr;
	else
		base = of_read_number(&addrp[2], 1);

	/* Try to guess an index... If we have subdevices of the pci dev,
	 * we get to their "reg" property
	 */
	if (np != pci_dev) {
		const __be32 *reg = of_get_property(np, "reg", NULL);
		if (reg && (be32_to_cpup(reg) < 4))
			index = lindex = be32_to_cpup(reg);
	}

	/* Local index means it's the Nth port in the PCI chip. Unfortunately
	 * the offset to add here is device specific. We know about those
	 * EXAR ports and we default to the most common case. If your UART
	 * doesn't work for these settings, you'll have to add your own special
	 * cases here
	 */
	if (of_device_is_compatible(pci_dev, "pci13a8,152") ||
	    of_device_is_compatible(pci_dev, "pci13a8,154") ||
	    of_device_is_compatible(pci_dev, "pci13a8,158")) {
		addr += 0x200 * lindex;
		base += 0x200 * lindex;
	} else {
		addr += 8 * lindex;
		base += 8 * lindex;
	}

	/* Add port, irq will be dealt with later. We passed a translated
	 * IO port value. It will be fixed up later along with the irq
	 */
	return add_legacy_port(np, index, iotype, base, addr, 0,
			       legacy_port_flags, np != pci_dev);
}
#endif

static void __init setup_legacy_serial_console(int console)
{
	struct legacy_serial_info *info = &legacy_serial_infos[console];
	struct plat_serial8250_port *port = &legacy_serial_ports[console];
	void __iomem *addr;
	unsigned int stride;

	stride = 1 << port->regshift;

	/* Check if a translated MMIO address has been found */
	if (info->taddr) {
		addr = ioremap(info->taddr, 0x1000);
		if (addr == NULL)
			return;
		udbg_uart_init_mmio(addr, stride);
	} else {
		/* Check if it's PIO and we support untranslated PIO */
		if (port->iotype == UPIO_PORT && isa_io_special)
			udbg_uart_init_pio(port->iobase, stride);
		else
			return;
	}

	/* Try to query the current speed */
	if (info->speed == 0)
		info->speed = udbg_probe_uart_speed(info->clock);

	/* Set it up */
	DBG("default console speed = %d\n", info->speed);
	udbg_uart_setup(info->speed, info->clock);
}

/*
 * This is called very early, as part of setup_system() or eventually
 * setup_arch(), basically before anything else in this file. This function
 * will try to build a list of all the available 8250-compatible serial ports
 * in the machine using the Open Firmware device-tree. It currently only deals
 * with ISA and PCI busses but could be extended. It allows a very early boot
 * console to be initialized, that list is also used later to provide 8250 with
 * the machine non-PCI ports and to properly pick the default console port
 */
void __init find_legacy_serial_ports(void)
{
	struct device_node *np, *stdout = NULL;
	const char *path;
	int index;

	DBG(" -> find_legacy_serial_port()\n");

	/* Now find out if one of these is out firmware console */
	path = of_get_property(of_chosen, "linux,stdout-path", NULL);
	if (path != NULL) {
		stdout = of_find_node_by_path(path);
		if (stdout)
			DBG("stdout is %s\n", stdout->full_name);
	} else {
		DBG(" no linux,stdout-path !\n");
	}

	/* Iterate over all the 16550 ports, looking for known parents */
	for_each_compatible_node(np, "serial", "ns16550") {
		struct device_node *parent = of_get_parent(np);
		if (!parent)
			continue;
		if (of_match_node(legacy_serial_parents, parent) != NULL) {
			if (of_device_is_available(np)) {
				index = add_legacy_soc_port(np, np);
				if (index >= 0 && np == stdout)
					legacy_serial_console = index;
			}
		}
		of_node_put(parent);
	}

	/* Next, fill our array with ISA ports */
	for_each_node_by_type(np, "serial") {
		struct device_node *isa = of_get_parent(np);
		if (isa && (!strcmp(isa->name, "isa") ||
			    !strcmp(isa->name, "lpc"))) {
			if (of_device_is_available(np)) {
				index = add_legacy_isa_port(np, isa);
				if (index >= 0 && np == stdout)
					legacy_serial_console = index;
			}
		}
		of_node_put(isa);
	}

#ifdef CONFIG_PCI
	/* Next, try to locate PCI ports */
	for (np = NULL; (np = of_find_all_nodes(np));) {
		struct device_node *pci, *parent = of_get_parent(np);
		if (parent && !strcmp(parent->name, "isa")) {
			of_node_put(parent);
			continue;
		}
		if (strcmp(np->name, "serial") && strcmp(np->type, "serial")) {
			of_node_put(parent);
			continue;
		}
		/* Check for known pciclass, and also check whether we have
		 * a device with child nodes for ports or not
		 */
		if (of_device_is_compatible(np, "pciclass,0700") ||
		    of_device_is_compatible(np, "pciclass,070002"))
			pci = np;
		else if (of_device_is_compatible(parent, "pciclass,0700") ||
			 of_device_is_compatible(parent, "pciclass,070002"))
			pci = parent;
		else {
			of_node_put(parent);
			continue;
		}
		index = add_legacy_pci_port(np, pci);
		if (index >= 0 && np == stdout)
			legacy_serial_console = index;
		of_node_put(parent);
	}
#endif

	DBG("legacy_serial_console = %d\n", legacy_serial_console);
	if (legacy_serial_console >= 0)
		setup_legacy_serial_console(legacy_serial_console);
	DBG(" <- find_legacy_serial_port()\n");
}

static struct platform_device serial_device = {
	.name	= "serial8250",
	.id	= PLAT8250_DEV_PLATFORM,
	.dev	= {
		.platform_data = legacy_serial_ports,
	},
};

static void __init fixup_port_irq(int index,
				  struct device_node *np,
				  struct plat_serial8250_port *port)
{
	unsigned int virq;

	DBG("fixup_port_irq(%d)\n", index);

	virq = irq_of_parse_and_map(np, 0);
	if (!virq && legacy_serial_infos[index].irq_check_parent) {
		np = of_get_parent(np);
		if (np == NULL)
			return;
		virq = irq_of_parse_and_map(np, 0);
		of_node_put(np);
	}
	if (!virq)
		return;

	port->irq = virq;

#ifdef CONFIG_SERIAL_8250_FSL
	if (of_device_is_compatible(np, "fsl,ns16550"))
		port->handle_irq = fsl8250_handle_irq;
#endif
}

static void __init fixup_port_pio(int index,
				  struct device_node *np,
				  struct plat_serial8250_port *port)
{
#ifdef CONFIG_PCI
	struct pci_controller *hose;

	DBG("fixup_port_pio(%d)\n", index);

	hose = pci_find_hose_for_OF_device(np);
	if (hose) {
		unsigned long offset = (unsigned long)hose->io_base_virt -
#ifdef CONFIG_PPC64
			pci_io_base;
#else
			isa_io_base;
#endif
		DBG("port %d, IO %lx -> %lx\n",
		    index, port->iobase, port->iobase + offset);
		port->iobase += offset;
	}
#endif
}

static void __init fixup_port_mmio(int index,
				   struct device_node *np,
				   struct plat_serial8250_port *port)
{
	DBG("fixup_port_mmio(%d)\n", index);

	port->membase = ioremap(port->mapbase, 0x100);
}

/*
 * This is called as an arch initcall, hopefully before the PCI bus is
 * probed and/or the 8250 driver loaded since we need to register our
 * platform devices before 8250 PCI ones are detected as some of them
 * must properly "override" the platform ones.
 *
 * This function fixes up the interrupt value for platform ports as it
 * couldn't be done earlier before interrupt maps have been parsed. It
 * also "corrects" the IO address for PIO ports for the same reason,
 * since earlier, the PHBs virtual IO space wasn't assigned yet. It then
 * registers all those platform ports for use by the 8250 driver when it
 * finally loads.
 */
static int __init serial_dev_init(void)
{
	int i;

	if (legacy_serial_count == 0)
		return -ENODEV;

	/*
	 * Before we register the platform serial devices, we need
	 * to fixup their interrupts and their IO ports.
	 */
	DBG("Fixing serial ports interrupts and IO ports ...\n");

	for (i = 0; i < legacy_serial_count; i++) {
		struct plat_serial8250_port *port = &legacy_serial_ports[i];
		struct device_node *np = legacy_serial_infos[i].np;

		if (!port->irq)
			fixup_port_irq(i, np, port);
		if (port->iotype == UPIO_PORT)
			fixup_port_pio(i, np, port);
		if ((port->iotype == UPIO_MEM) || (port->iotype == UPIO_TSI))
			fixup_port_mmio(i, np, port);
	}

	DBG("Registering platform serial ports\n");

	return platform_device_register(&serial_device);
}
device_initcall(serial_dev_init);


#ifdef CONFIG_SERIAL_8250_CONSOLE
/*
 * This is called very early, as part of console_init() (typically just after
 * time_init()). This function is respondible for trying to find a good
 * default console on serial ports. It tries to match the open firmware
 * default output with one of the available serial console drivers that have
 * been probed earlier by find_legacy_serial_ports()
 */
static int __init check_legacy_serial_console(void)
{
	struct device_node *prom_stdout = NULL;
	int i, speed = 0, offset = 0;
	const char *name;
	const __be32 *spd;

	DBG(" -> check_legacy_serial_console()\n");

	/* The user has requested a console so this is already set up. */
	if (strstr(boot_command_line, "console=")) {
		DBG(" console was specified !\n");
		return -EBUSY;
	}

	if (!of_chosen) {
		DBG(" of_chosen is NULL !\n");
		return -ENODEV;
	}

	if (legacy_serial_console < 0) {
		DBG(" legacy_serial_console not found !\n");
		return -ENODEV;
	}
	/* We are getting a weird phandle from OF ... */
	/* ... So use the full path instead */
	name = of_get_property(of_chosen, "linux,stdout-path", NULL);
	if (name == NULL) {
		DBG(" no linux,stdout-path !\n");
		return -ENODEV;
	}
	prom_stdout = of_find_node_by_path(name);
	if (!prom_stdout) {
		DBG(" can't find stdout package %s !\n", name);
		return -ENODEV;
	}
	DBG("stdout is %s\n", prom_stdout->full_name);

	name = of_get_property(prom_stdout, "name", NULL);
	if (!name) {
		DBG(" stdout package has no name !\n");
		goto not_found;
	}
	spd = of_get_property(prom_stdout, "current-speed", NULL);
	if (spd)
		speed = be32_to_cpup(spd);

	if (strcmp(name, "serial") != 0)
		goto not_found;

	/* Look for it in probed array */
	for (i = 0; i < legacy_serial_count; i++) {
		if (prom_stdout != legacy_serial_infos[i].np)
			continue;
		offset = i;
		speed = legacy_serial_infos[i].speed;
		break;
	}
	if (i >= legacy_serial_count)
		goto not_found;

	of_node_put(prom_stdout);

	DBG("Found serial console at ttyS%d\n", offset);

	if (speed) {
		static char __initdata opt[16];
		sprintf(opt, "%d", speed);
		return add_preferred_console("ttyS", offset, opt);
	} else
		return add_preferred_console("ttyS", offset, NULL);

 not_found:
	DBG("No preferred console found !\n");
	of_node_put(prom_stdout);
	return -ENODEV;
}
console_initcall(check_legacy_serial_console);

#endif /* CONFIG_SERIAL_8250_CONSOLE */