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legacy_serial.c

#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_device.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 struct __initdata of_device_id legacy_serial_parents[] = {
      {.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 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 u32 *clk, *spd;
      u32 clock = BASE_BAUD * 16;
      int index;

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

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

      /* 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 != 0) {
            /* 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_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 ? *spd : 0;
      legacy_serial_infos[index].irq_check_parent = irq_check_parent;

      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 u32 *addrp;
      upf_t flags = UPF_BOOT_AUTOCONF | UPF_SKIP_TEST | UPF_SHARE_IRQ
            | UPF_FIXED_PORT;
      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-shift or offset, don't try to use it */
      if ((of_get_property(np, "reg-shift", NULL) != NULL) ||
            (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, NO_IRQ, flags, 0);
      else
            return add_legacy_port(np, -1, UPIO_MEM, addr, addr, NO_IRQ, flags, 0);
}

static int __init add_legacy_isa_port(struct device_node *np,
                              struct device_node *isa_brg)
{
      const u32 *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 (!(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
       */
      taddr = of_translate_address(np, reg);
      if (taddr == OF_BAD_ADDR)
            taddr = 0;

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

}

#ifdef CONFIG_PCI
static int __init add_legacy_pci_port(struct device_node *np,
                              struct device_node *pci_dev)
{
      u64 addr, base;
      const u32 *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 = addrp[2];

      /* Try to guess an index... If we have subdevices of the pci dev,
       * we get to their "reg" property
       */
      if (np != pci_dev) {
            const u32 *reg = of_get_property(np, "reg", NULL);
            if (reg && (*reg < 4))
                  index = lindex = *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, NO_IRQ,
                         UPF_BOOT_AUTOCONF, np != pci_dev);
}
#endif

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

      if (info->taddr == 0)
            return;
      addr = ioremap(info->taddr, 0x1000);
      if (addr == NULL)
            return;
      if (info->speed == 0)
            info->speed = udbg_probe_uart_speed(addr, info->clock);
      DBG("default console speed = %d\n", info->speed);
      udbg_init_uart(addr, 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) {
                  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")) {
                  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 wether 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 == NO_IRQ && 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 == NO_IRQ)
            return;

      port->irq = virq;
}

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 platfrom 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 == NO_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 u32 *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 = *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 */

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