// SPDX-License-Identifier: GPL-2.0
#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 %pOF\n",
               index, np);
        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 (of_node_is_type(tsi, "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(%pOF)\n", np);

        /* 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(%pOF)\n", np);

        /* 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)
                path = of_get_property(of_chosen, "stdout-path", NULL);
        if (path != NULL) {
                stdout = of_find_node_by_path(path);
                if (stdout)
                        DBG("stdout is %pOF\n", stdout);
        } 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 (of_node_name_eq(isa, "isa") || of_node_name_eq(isa, "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 (of_node_name_eq(parent, "isa")) {
                        of_node_put(parent);
                        continue;
                }
                if (!of_node_name_eq(np, "serial") &&
                    !of_node_is_type(np, "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;
                port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_8250_CONSOLE);
        }
#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)
                name = of_get_property(of_chosen, "stdout-path", NULL);
        if (name == NULL) {
                DBG(" no 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 %pOF\n", prom_stdout);

        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 */