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Linux/arch/powerpc/kernel/legacy_serial.c

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

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