1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/kernel.h>
3 #include <linux/serial.h>
4 #include <linux/serial_8250.h>
5 #include <linux/serial_core.h>
6 #include <linux/console.h>
7 #include <linux/pci.h>
8 #include <linux/of_address.h>
9 #include <linux/of_device.h>
10 #include <linux/serial_reg.h>
11 #include <asm/io.h>
12 #include <asm/mmu.h>
13 #include <asm/prom.h>
14 #include <asm/serial.h>
15 #include <asm/udbg.h>
16 #include <asm/pci-bridge.h>
17 #include <asm/ppc-pci.h>
18 
19 #undef DEBUG
20 
21 #ifdef DEBUG
22 #define DBG(fmt...) do { printk(fmt); } while(0)
23 #else
24 #define DBG(fmt...) do { } while(0)
25 #endif
26 
27 #define MAX_LEGACY_SERIAL_PORTS	8
28 
29 static struct plat_serial8250_port
30 legacy_serial_ports[MAX_LEGACY_SERIAL_PORTS+1];
31 static struct legacy_serial_info {
32 	struct device_node		*np;
33 	unsigned int			speed;
34 	unsigned int			clock;
35 	int				irq_check_parent;
36 	phys_addr_t			taddr;
37 } legacy_serial_infos[MAX_LEGACY_SERIAL_PORTS];
38 
39 static const struct of_device_id legacy_serial_parents[] __initconst = {
40 	{.type = "soc",},
41 	{.type = "tsi-bridge",},
42 	{.type = "opb", },
43 	{.compatible = "ibm,opb",},
44 	{.compatible = "simple-bus",},
45 	{.compatible = "wrs,epld-localbus",},
46 	{},
47 };
48 
49 static unsigned int legacy_serial_count;
50 static int legacy_serial_console = -1;
51 
52 static const upf_t legacy_port_flags = UPF_BOOT_AUTOCONF | UPF_SKIP_TEST |
53 	UPF_SHARE_IRQ | UPF_FIXED_PORT;
54 
55 static unsigned int tsi_serial_in(struct uart_port *p, int offset)
56 {
57 	unsigned int tmp;
58 	offset = offset << p->regshift;
59 	if (offset == UART_IIR) {
60 		tmp = readl(p->membase + (UART_IIR & ~3));
61 		return (tmp >> 16) & 0xff; /* UART_IIR % 4 == 2 */
62 	} else
63 		return readb(p->membase + offset);
64 }
65 
66 static void tsi_serial_out(struct uart_port *p, int offset, int value)
67 {
68 	offset = offset << p->regshift;
69 	if (!((offset == UART_IER) && (value & UART_IER_UUE)))
70 		writeb(value, p->membase + offset);
71 }
72 
73 static int __init add_legacy_port(struct device_node *np, int want_index,
74 				  int iotype, phys_addr_t base,
75 				  phys_addr_t taddr, unsigned long irq,
76 				  upf_t flags, int irq_check_parent)
77 {
78 	const __be32 *clk, *spd, *rs;
79 	u32 clock = BASE_BAUD * 16;
80 	u32 shift = 0;
81 	int index;
82 
83 	/* get clock freq. if present */
84 	clk = of_get_property(np, "clock-frequency", NULL);
85 	if (clk && *clk)
86 		clock = be32_to_cpup(clk);
87 
88 	/* get default speed if present */
89 	spd = of_get_property(np, "current-speed", NULL);
90 
91 	/* get register shift if present */
92 	rs = of_get_property(np, "reg-shift", NULL);
93 	if (rs && *rs)
94 		shift = be32_to_cpup(rs);
95 
96 	/* If we have a location index, then try to use it */
97 	if (want_index >= 0 && want_index < MAX_LEGACY_SERIAL_PORTS)
98 		index = want_index;
99 	else
100 		index = legacy_serial_count;
101 
102 	/* if our index is still out of range, that mean that
103 	 * array is full, we could scan for a free slot but that
104 	 * make little sense to bother, just skip the port
105 	 */
106 	if (index >= MAX_LEGACY_SERIAL_PORTS)
107 		return -1;
108 	if (index >= legacy_serial_count)
109 		legacy_serial_count = index + 1;
110 
111 	/* Check if there is a port who already claimed our slot */
112 	if (legacy_serial_infos[index].np != NULL) {
113 		/* if we still have some room, move it, else override */
114 		if (legacy_serial_count < MAX_LEGACY_SERIAL_PORTS) {
115 			printk(KERN_DEBUG "Moved legacy port %d -> %d\n",
116 			       index, legacy_serial_count);
117 			legacy_serial_ports[legacy_serial_count] =
118 				legacy_serial_ports[index];
119 			legacy_serial_infos[legacy_serial_count] =
120 				legacy_serial_infos[index];
121 			legacy_serial_count++;
122 		} else {
123 			printk(KERN_DEBUG "Replacing legacy port %d\n", index);
124 		}
125 	}
126 
127 	/* Now fill the entry */
128 	memset(&legacy_serial_ports[index], 0,
129 	       sizeof(struct plat_serial8250_port));
130 	if (iotype == UPIO_PORT)
131 		legacy_serial_ports[index].iobase = base;
132 	else
133 		legacy_serial_ports[index].mapbase = base;
134 
135 	legacy_serial_ports[index].iotype = iotype;
136 	legacy_serial_ports[index].uartclk = clock;
137 	legacy_serial_ports[index].irq = irq;
138 	legacy_serial_ports[index].flags = flags;
139 	legacy_serial_ports[index].regshift = shift;
140 	legacy_serial_infos[index].taddr = taddr;
141 	legacy_serial_infos[index].np = of_node_get(np);
142 	legacy_serial_infos[index].clock = clock;
143 	legacy_serial_infos[index].speed = spd ? be32_to_cpup(spd) : 0;
144 	legacy_serial_infos[index].irq_check_parent = irq_check_parent;
145 
146 	if (iotype == UPIO_TSI) {
147 		legacy_serial_ports[index].serial_in = tsi_serial_in;
148 		legacy_serial_ports[index].serial_out = tsi_serial_out;
149 	}
150 
151 	printk(KERN_DEBUG "Found legacy serial port %d for %pOF\n",
152 	       index, np);
153 	printk(KERN_DEBUG "  %s=%llx, taddr=%llx, irq=%lx, clk=%d, speed=%d\n",
154 	       (iotype == UPIO_PORT) ? "port" : "mem",
155 	       (unsigned long long)base, (unsigned long long)taddr, irq,
156 	       legacy_serial_ports[index].uartclk,
157 	       legacy_serial_infos[index].speed);
158 
159 	return index;
160 }
161 
162 static int __init add_legacy_soc_port(struct device_node *np,
163 				      struct device_node *soc_dev)
164 {
165 	u64 addr;
166 	const __be32 *addrp;
167 	struct device_node *tsi = of_get_parent(np);
168 
169 	/* We only support ports that have a clock frequency properly
170 	 * encoded in the device-tree.
171 	 */
172 	if (of_get_property(np, "clock-frequency", NULL) == NULL)
173 		return -1;
174 
175 	/* if reg-offset don't try to use it */
176 	if ((of_get_property(np, "reg-offset", NULL) != NULL))
177 		return -1;
178 
179 	/* if rtas uses this device, don't try to use it as well */
180 	if (of_get_property(np, "used-by-rtas", NULL) != NULL)
181 		return -1;
182 
183 	/* Get the address */
184 	addrp = of_get_address(soc_dev, 0, NULL, NULL);
185 	if (addrp == NULL)
186 		return -1;
187 
188 	addr = of_translate_address(soc_dev, addrp);
189 	if (addr == OF_BAD_ADDR)
190 		return -1;
191 
192 	/* Add port, irq will be dealt with later. We passed a translated
193 	 * IO port value. It will be fixed up later along with the irq
194 	 */
195 	if (of_node_is_type(tsi, "tsi-bridge"))
196 		return add_legacy_port(np, -1, UPIO_TSI, addr, addr,
197 				       0, legacy_port_flags, 0);
198 	else
199 		return add_legacy_port(np, -1, UPIO_MEM, addr, addr,
200 				       0, legacy_port_flags, 0);
201 }
202 
203 static int __init add_legacy_isa_port(struct device_node *np,
204 				      struct device_node *isa_brg)
205 {
206 	const __be32 *reg;
207 	const char *typep;
208 	int index = -1;
209 	u64 taddr;
210 
211 	DBG(" -> add_legacy_isa_port(%pOF)\n", np);
212 
213 	/* Get the ISA port number */
214 	reg = of_get_property(np, "reg", NULL);
215 	if (reg == NULL)
216 		return -1;
217 
218 	/* Verify it's an IO port, we don't support anything else */
219 	if (!(be32_to_cpu(reg[0]) & 0x00000001))
220 		return -1;
221 
222 	/* Now look for an "ibm,aix-loc" property that gives us ordering
223 	 * if any...
224 	 */
225 	typep = of_get_property(np, "ibm,aix-loc", NULL);
226 
227 	/* If we have a location index, then use it */
228 	if (typep && *typep == 'S')
229 		index = simple_strtol(typep+1, NULL, 0) - 1;
230 
231 	/* Translate ISA address. If it fails, we still register the port
232 	 * with no translated address so that it can be picked up as an IO
233 	 * port later by the serial driver
234 	 *
235 	 * Note: Don't even try on P8 lpc, we know it's not directly mapped
236 	 */
237 	if (!of_device_is_compatible(isa_brg, "ibm,power8-lpc") ||
238 	    of_get_property(isa_brg, "ranges", NULL)) {
239 		taddr = of_translate_address(np, reg);
240 		if (taddr == OF_BAD_ADDR)
241 			taddr = 0;
242 	} else
243 		taddr = 0;
244 
245 	/* Add port, irq will be dealt with later */
246 	return add_legacy_port(np, index, UPIO_PORT, be32_to_cpu(reg[1]),
247 			       taddr, 0, legacy_port_flags, 0);
248 
249 }
250 
251 #ifdef CONFIG_PCI
252 static int __init add_legacy_pci_port(struct device_node *np,
253 				      struct device_node *pci_dev)
254 {
255 	u64 addr, base;
256 	const __be32 *addrp;
257 	unsigned int flags;
258 	int iotype, index = -1, lindex = 0;
259 
260 	DBG(" -> add_legacy_pci_port(%pOF)\n", np);
261 
262 	/* We only support ports that have a clock frequency properly
263 	 * encoded in the device-tree (that is have an fcode). Anything
264 	 * else can't be used that early and will be normally probed by
265 	 * the generic 8250_pci driver later on. The reason is that 8250
266 	 * compatible UARTs on PCI need all sort of quirks (port offsets
267 	 * etc...) that this code doesn't know about
268 	 */
269 	if (of_get_property(np, "clock-frequency", NULL) == NULL)
270 		return -1;
271 
272 	/* Get the PCI address. Assume BAR 0 */
273 	addrp = of_get_pci_address(pci_dev, 0, NULL, &flags);
274 	if (addrp == NULL)
275 		return -1;
276 
277 	/* We only support BAR 0 for now */
278 	iotype = (flags & IORESOURCE_MEM) ? UPIO_MEM : UPIO_PORT;
279 	addr = of_translate_address(pci_dev, addrp);
280 	if (addr == OF_BAD_ADDR)
281 		return -1;
282 
283 	/* Set the IO base to the same as the translated address for MMIO,
284 	 * or to the domain local IO base for PIO (it will be fixed up later)
285 	 */
286 	if (iotype == UPIO_MEM)
287 		base = addr;
288 	else
289 		base = of_read_number(&addrp[2], 1);
290 
291 	/* Try to guess an index... If we have subdevices of the pci dev,
292 	 * we get to their "reg" property
293 	 */
294 	if (np != pci_dev) {
295 		const __be32 *reg = of_get_property(np, "reg", NULL);
296 		if (reg && (be32_to_cpup(reg) < 4))
297 			index = lindex = be32_to_cpup(reg);
298 	}
299 
300 	/* Local index means it's the Nth port in the PCI chip. Unfortunately
301 	 * the offset to add here is device specific. We know about those
302 	 * EXAR ports and we default to the most common case. If your UART
303 	 * doesn't work for these settings, you'll have to add your own special
304 	 * cases here
305 	 */
306 	if (of_device_is_compatible(pci_dev, "pci13a8,152") ||
307 	    of_device_is_compatible(pci_dev, "pci13a8,154") ||
308 	    of_device_is_compatible(pci_dev, "pci13a8,158")) {
309 		addr += 0x200 * lindex;
310 		base += 0x200 * lindex;
311 	} else {
312 		addr += 8 * lindex;
313 		base += 8 * lindex;
314 	}
315 
316 	/* Add port, irq will be dealt with later. We passed a translated
317 	 * IO port value. It will be fixed up later along with the irq
318 	 */
319 	return add_legacy_port(np, index, iotype, base, addr, 0,
320 			       legacy_port_flags, np != pci_dev);
321 }
322 #endif
323 
324 static void __init setup_legacy_serial_console(int console)
325 {
326 	struct legacy_serial_info *info = &legacy_serial_infos[console];
327 	struct plat_serial8250_port *port = &legacy_serial_ports[console];
328 	void __iomem *addr;
329 	unsigned int stride;
330 
331 	stride = 1 << port->regshift;
332 
333 	/* Check if a translated MMIO address has been found */
334 	if (info->taddr) {
335 		addr = ioremap(info->taddr, 0x1000);
336 		if (addr == NULL)
337 			return;
338 		udbg_uart_init_mmio(addr, stride);
339 	} else {
340 		/* Check if it's PIO and we support untranslated PIO */
341 		if (port->iotype == UPIO_PORT && isa_io_special)
342 			udbg_uart_init_pio(port->iobase, stride);
343 		else
344 			return;
345 	}
346 
347 	/* Try to query the current speed */
348 	if (info->speed == 0)
349 		info->speed = udbg_probe_uart_speed(info->clock);
350 
351 	/* Set it up */
352 	DBG("default console speed = %d\n", info->speed);
353 	udbg_uart_setup(info->speed, info->clock);
354 }
355 
356 /*
357  * This is called very early, as part of setup_system() or eventually
358  * setup_arch(), basically before anything else in this file. This function
359  * will try to build a list of all the available 8250-compatible serial ports
360  * in the machine using the Open Firmware device-tree. It currently only deals
361  * with ISA and PCI busses but could be extended. It allows a very early boot
362  * console to be initialized, that list is also used later to provide 8250 with
363  * the machine non-PCI ports and to properly pick the default console port
364  */
365 void __init find_legacy_serial_ports(void)
366 {
367 	struct device_node *np, *stdout = NULL;
368 	const char *path;
369 	int index;
370 
371 	DBG(" -> find_legacy_serial_port()\n");
372 
373 	/* Now find out if one of these is out firmware console */
374 	path = of_get_property(of_chosen, "linux,stdout-path", NULL);
375 	if (path == NULL)
376 		path = of_get_property(of_chosen, "stdout-path", NULL);
377 	if (path != NULL) {
378 		stdout = of_find_node_by_path(path);
379 		if (stdout)
380 			DBG("stdout is %pOF\n", stdout);
381 	} else {
382 		DBG(" no linux,stdout-path !\n");
383 	}
384 
385 	/* Iterate over all the 16550 ports, looking for known parents */
386 	for_each_compatible_node(np, "serial", "ns16550") {
387 		struct device_node *parent = of_get_parent(np);
388 		if (!parent)
389 			continue;
390 		if (of_match_node(legacy_serial_parents, parent) != NULL) {
391 			if (of_device_is_available(np)) {
392 				index = add_legacy_soc_port(np, np);
393 				if (index >= 0 && np == stdout)
394 					legacy_serial_console = index;
395 			}
396 		}
397 		of_node_put(parent);
398 	}
399 
400 	/* Next, fill our array with ISA ports */
401 	for_each_node_by_type(np, "serial") {
402 		struct device_node *isa = of_get_parent(np);
403 		if (of_node_name_eq(isa, "isa") || of_node_name_eq(isa, "lpc")) {
404 			if (of_device_is_available(np)) {
405 				index = add_legacy_isa_port(np, isa);
406 				if (index >= 0 && np == stdout)
407 					legacy_serial_console = index;
408 			}
409 		}
410 		of_node_put(isa);
411 	}
412 
413 #ifdef CONFIG_PCI
414 	/* Next, try to locate PCI ports */
415 	for (np = NULL; (np = of_find_all_nodes(np));) {
416 		struct device_node *pci, *parent = of_get_parent(np);
417 		if (of_node_name_eq(parent, "isa")) {
418 			of_node_put(parent);
419 			continue;
420 		}
421 		if (!of_node_name_eq(np, "serial") &&
422 		    !of_node_is_type(np, "serial")) {
423 			of_node_put(parent);
424 			continue;
425 		}
426 		/* Check for known pciclass, and also check whether we have
427 		 * a device with child nodes for ports or not
428 		 */
429 		if (of_device_is_compatible(np, "pciclass,0700") ||
430 		    of_device_is_compatible(np, "pciclass,070002"))
431 			pci = np;
432 		else if (of_device_is_compatible(parent, "pciclass,0700") ||
433 			 of_device_is_compatible(parent, "pciclass,070002"))
434 			pci = parent;
435 		else {
436 			of_node_put(parent);
437 			continue;
438 		}
439 		index = add_legacy_pci_port(np, pci);
440 		if (index >= 0 && np == stdout)
441 			legacy_serial_console = index;
442 		of_node_put(parent);
443 	}
444 #endif
445 
446 	DBG("legacy_serial_console = %d\n", legacy_serial_console);
447 	if (legacy_serial_console >= 0)
448 		setup_legacy_serial_console(legacy_serial_console);
449 	DBG(" <- find_legacy_serial_port()\n");
450 }
451 
452 static struct platform_device serial_device = {
453 	.name	= "serial8250",
454 	.id	= PLAT8250_DEV_PLATFORM,
455 	.dev	= {
456 		.platform_data = legacy_serial_ports,
457 	},
458 };
459 
460 static void __init fixup_port_irq(int index,
461 				  struct device_node *np,
462 				  struct plat_serial8250_port *port)
463 {
464 	unsigned int virq;
465 
466 	DBG("fixup_port_irq(%d)\n", index);
467 
468 	virq = irq_of_parse_and_map(np, 0);
469 	if (!virq && legacy_serial_infos[index].irq_check_parent) {
470 		np = of_get_parent(np);
471 		if (np == NULL)
472 			return;
473 		virq = irq_of_parse_and_map(np, 0);
474 		of_node_put(np);
475 	}
476 	if (!virq)
477 		return;
478 
479 	port->irq = virq;
480 
481 #ifdef CONFIG_SERIAL_8250_FSL
482 	if (of_device_is_compatible(np, "fsl,ns16550"))
483 		port->handle_irq = fsl8250_handle_irq;
484 #endif
485 }
486 
487 static void __init fixup_port_pio(int index,
488 				  struct device_node *np,
489 				  struct plat_serial8250_port *port)
490 {
491 #ifdef CONFIG_PCI
492 	struct pci_controller *hose;
493 
494 	DBG("fixup_port_pio(%d)\n", index);
495 
496 	hose = pci_find_hose_for_OF_device(np);
497 	if (hose) {
498 		unsigned long offset = (unsigned long)hose->io_base_virt -
499 #ifdef CONFIG_PPC64
500 			pci_io_base;
501 #else
502 			isa_io_base;
503 #endif
504 		DBG("port %d, IO %lx -> %lx\n",
505 		    index, port->iobase, port->iobase + offset);
506 		port->iobase += offset;
507 	}
508 #endif
509 }
510 
511 static void __init fixup_port_mmio(int index,
512 				   struct device_node *np,
513 				   struct plat_serial8250_port *port)
514 {
515 	DBG("fixup_port_mmio(%d)\n", index);
516 
517 	port->membase = ioremap(port->mapbase, 0x100);
518 }
519 
520 /*
521  * This is called as an arch initcall, hopefully before the PCI bus is
522  * probed and/or the 8250 driver loaded since we need to register our
523  * platform devices before 8250 PCI ones are detected as some of them
524  * must properly "override" the platform ones.
525  *
526  * This function fixes up the interrupt value for platform ports as it
527  * couldn't be done earlier before interrupt maps have been parsed. It
528  * also "corrects" the IO address for PIO ports for the same reason,
529  * since earlier, the PHBs virtual IO space wasn't assigned yet. It then
530  * registers all those platform ports for use by the 8250 driver when it
531  * finally loads.
532  */
533 static int __init serial_dev_init(void)
534 {
535 	int i;
536 
537 	if (legacy_serial_count == 0)
538 		return -ENODEV;
539 
540 	/*
541 	 * Before we register the platform serial devices, we need
542 	 * to fixup their interrupts and their IO ports.
543 	 */
544 	DBG("Fixing serial ports interrupts and IO ports ...\n");
545 
546 	for (i = 0; i < legacy_serial_count; i++) {
547 		struct plat_serial8250_port *port = &legacy_serial_ports[i];
548 		struct device_node *np = legacy_serial_infos[i].np;
549 
550 		if (!port->irq)
551 			fixup_port_irq(i, np, port);
552 		if (port->iotype == UPIO_PORT)
553 			fixup_port_pio(i, np, port);
554 		if ((port->iotype == UPIO_MEM) || (port->iotype == UPIO_TSI))
555 			fixup_port_mmio(i, np, port);
556 	}
557 
558 	DBG("Registering platform serial ports\n");
559 
560 	return platform_device_register(&serial_device);
561 }
562 device_initcall(serial_dev_init);
563 
564 
565 #ifdef CONFIG_SERIAL_8250_CONSOLE
566 /*
567  * This is called very early, as part of console_init() (typically just after
568  * time_init()). This function is respondible for trying to find a good
569  * default console on serial ports. It tries to match the open firmware
570  * default output with one of the available serial console drivers that have
571  * been probed earlier by find_legacy_serial_ports()
572  */
573 static int __init check_legacy_serial_console(void)
574 {
575 	struct device_node *prom_stdout = NULL;
576 	int i, speed = 0, offset = 0;
577 	const char *name;
578 	const __be32 *spd;
579 
580 	DBG(" -> check_legacy_serial_console()\n");
581 
582 	/* The user has requested a console so this is already set up. */
583 	if (strstr(boot_command_line, "console=")) {
584 		DBG(" console was specified !\n");
585 		return -EBUSY;
586 	}
587 
588 	if (!of_chosen) {
589 		DBG(" of_chosen is NULL !\n");
590 		return -ENODEV;
591 	}
592 
593 	if (legacy_serial_console < 0) {
594 		DBG(" legacy_serial_console not found !\n");
595 		return -ENODEV;
596 	}
597 	/* We are getting a weird phandle from OF ... */
598 	/* ... So use the full path instead */
599 	name = of_get_property(of_chosen, "linux,stdout-path", NULL);
600 	if (name == NULL)
601 		name = of_get_property(of_chosen, "stdout-path", NULL);
602 	if (name == NULL) {
603 		DBG(" no stdout-path !\n");
604 		return -ENODEV;
605 	}
606 	prom_stdout = of_find_node_by_path(name);
607 	if (!prom_stdout) {
608 		DBG(" can't find stdout package %s !\n", name);
609 		return -ENODEV;
610 	}
611 	DBG("stdout is %pOF\n", prom_stdout);
612 
613 	name = of_get_property(prom_stdout, "name", NULL);
614 	if (!name) {
615 		DBG(" stdout package has no name !\n");
616 		goto not_found;
617 	}
618 	spd = of_get_property(prom_stdout, "current-speed", NULL);
619 	if (spd)
620 		speed = be32_to_cpup(spd);
621 
622 	if (strcmp(name, "serial") != 0)
623 		goto not_found;
624 
625 	/* Look for it in probed array */
626 	for (i = 0; i < legacy_serial_count; i++) {
627 		if (prom_stdout != legacy_serial_infos[i].np)
628 			continue;
629 		offset = i;
630 		speed = legacy_serial_infos[i].speed;
631 		break;
632 	}
633 	if (i >= legacy_serial_count)
634 		goto not_found;
635 
636 	of_node_put(prom_stdout);
637 
638 	DBG("Found serial console at ttyS%d\n", offset);
639 
640 	if (speed) {
641 		static char __initdata opt[16];
642 		sprintf(opt, "%d", speed);
643 		return add_preferred_console("ttyS", offset, opt);
644 	} else
645 		return add_preferred_console("ttyS", offset, NULL);
646 
647  not_found:
648 	DBG("No preferred console found !\n");
649 	of_node_put(prom_stdout);
650 	return -ENODEV;
651 }
652 console_initcall(check_legacy_serial_console);
653 
654 #endif /* CONFIG_SERIAL_8250_CONSOLE */
655