legacy_serial.c

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#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 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 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;
    u32 clock = BASE_BAUD * 16;
    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);

    /* 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 ? 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 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 __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
     */
    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, be32_to_cpu(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 __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, 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) {
            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")) {
            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;

#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 == 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 __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 */