/* fdt_uart_test.c -- host test of the console's serial-line lookup
 * (kernel/src/hal/fdt_uart.c): which UART a board's devicetree names as its
 * console, where it is, and how its registers are laid out.
 *
 * No board is needed.  The test builds devicetrees shaped like the Milk-V
 * Mars's (JH7110), the Raspberry Pi 5's (BCM2712) and QEMU's riscv64 virt
 * machine's, with the values those boards' own devicetree sources give, and
 * checks what the lookup finds in each; then ones that must find nothing.
 * Given the path of a real blob and what it should give, it checks that too.
 *
 * Build and run, from the repository root:
 *
 *   cc -std=c99 -Wall -Wextra -Werror -Ikernel/include \
 *      tools/fdt_uart_test.c kernel/src/hal/fdt.c kernel/src/hal/fdt_uart.c \
 *      -o build/fdt_uart_test
 *   build/fdt_uart_test
 *   build/fdt_uart_test build/cache/raspi-<tag>/bcm2712-rpi-5-b.dtb pl011 0x107d001000 0 1
 *
 * It is not part of any build; like tools/ttftest.c it is run by hand.
 */
#include "starkernel/fdt.h"
#include "starkernel/fdt_uart.h"
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

static int failures = 0, checks = 0;
#define CHECK(c, ...) do { checks++; if (!(c)) { failures++; printf("FAIL %s:%d: ", __FILE__, __LINE__); printf(__VA_ARGS__); printf("\n"); } } while (0)

/* ---- a devicetree blob, written a token at a time ---- */
static unsigned char st[4096], strs[1024], blob[8192];
static unsigned st_len, strs_len;

static void put32(unsigned char *p, uint32_t v) { p[0] = (unsigned char)(v >> 24); p[1] = (unsigned char)(v >> 16); p[2] = (unsigned char)(v >> 8); p[3] = (unsigned char)v; }
static void tok(uint32_t v) { put32(st + st_len, v); st_len += 4; }
static void begin(const char *name)
{
    size_t n = strlen(name) + 1;
    tok(1);
    memcpy(st + st_len, name, n);
    st_len += (unsigned)n;
    while (st_len & 3u) st[st_len++] = 0;
}
static void end(void) { tok(2); }
static uint32_t str_off(const char *name)
{
    unsigned i = 0;
    while (i < strs_len) { if (strcmp((const char *)strs + i, name) == 0) return i; i += (unsigned)strlen((const char *)strs + i) + 1; }
    memcpy(strs + strs_len, name, strlen(name) + 1);
    i = strs_len; strs_len += (unsigned)strlen(name) + 1;
    return i;
}
static void prop(const char *name, const void *value, uint32_t len)
{
    tok(3); tok(len); tok(str_off(name));
    if (len) memcpy(st + st_len, value, len);
    st_len += len;
    while (st_len & 3u) st[st_len++] = 0;
}
static void prop_str(const char *name, const char *s) { prop(name, s, (uint32_t)strlen(s) + 1); }
static void prop_cells(const char *name, unsigned n, const uint32_t *c)
{
    unsigned char b[64];
    unsigned i;
    for (i = 0; i < n; i++) put32(b + 4 * i, c[i]);
    prop(name, b, 4 * n);
}
static void prop_u32(const char *name, uint32_t v) { prop_cells(name, 1, &v); }
static void start(void) { st_len = 0; strs_len = 0; begin(""); }
static const void *finish(void)
{
    unsigned off_struct = 40 + 16, off_strs;
    end(); tok(9);
    off_strs = off_struct + st_len;
    memset(blob, 0, sizeof blob);
    put32(blob + 0, 0xd00dfeedu);
    put32(blob + 4, off_strs + strs_len);
    put32(blob + 8, off_struct);
    put32(blob + 12, off_strs);
    put32(blob + 16, 40);
    put32(blob + 20, 17);
    put32(blob + 24, 16);
    put32(blob + 32, strs_len);
    put32(blob + 36, st_len);
    memcpy(blob + off_struct, st, st_len);
    memcpy(blob + off_strs, strs, strs_len);
    return blob;
}

static const char *kind_name(int k) { return k == FDT_UART_PL011 ? "pl011" : k == FDT_UART_16550 ? "16550" : "none"; }
static int is(const fdt_uart_t *u, int kind, uint64_t base, uint32_t shift, uint32_t width)
{
    return u->kind == kind && u->base == base && u->reg_shift == shift && u->io_width == width;
}
#define SHOW(u) kind_name((u).kind), (unsigned long long)(u).base, (unsigned)(u).reg_shift, (unsigned)(u).io_width

/* the Mars: jh7110.dtsi's uart0 and jh7110-common.dtsi's aliases and chosen */
static const void *mars(const char *stdout_path, const char *status, int with_ranges)
{
    static const uint32_t reg[4] = { 0, 0x10000000u, 0, 0x10000u };
    start();
    prop_u32("#address-cells", 2); prop_u32("#size-cells", 2);
    begin("aliases"); prop_str("serial0", "/soc/serial@10000000"); end();
    begin("chosen"); if (stdout_path) prop_str("stdout-path", stdout_path); end();
    begin("soc");
        prop_str("compatible", "simple-bus");
        prop_u32("#address-cells", 2); prop_u32("#size-cells", 2);
        if (with_ranges) prop("ranges", "", 0);
        begin("serial@10000000");
            prop("compatible", "starfive,jh7110-uart\0snps,dw-apb-uart", 38);
            prop_cells("reg", 4, reg);
            prop_u32("reg-io-width", 4); prop_u32("reg-shift", 2);
            if (status) prop_str("status", status);
        end();
    end();
    return finish();
}

/* the Pi 5: bcm2712.dtsi's soc bus and its debug UART, serial10 */
static const void *pi5(const char *compatible, unsigned compatible_len)
{
    static const uint32_t ranges[4] = { 0x7c000000u, 0x10, 0x7c000000u, 0x80000000u };
    static const uint32_t reg[2] = { 0x7d001000u, 0x200u };
    static const uint32_t rp1[4] = { 0xc0, 0x40030000u, 0, 0x100 };
    start();
    prop_u32("#address-cells", 2); prop_u32("#size-cells", 2);
    begin("aliases");
        prop_str("serial0", "/axi/pcie@1000120000/rp1/serial@30000");
        prop_str("serial10", "/soc@107c000000/serial@7d001000");
    end();
    begin("chosen"); prop_str("stdout-path", "serial10:115200n8"); end();
    begin("soc@107c000000");
        prop_str("compatible", "simple-bus");
        prop_u32("#address-cells", 1); prop_u32("#size-cells", 1);
        prop_cells("ranges", 4, ranges);
        begin("serial@7d001000");
            prop("compatible", compatible, compatible_len);
            prop_cells("reg", 2, reg);
            prop_str("status", "okay");
        end();
    end();
    begin("axi");
        prop_u32("#address-cells", 2); prop_u32("#size-cells", 2);
        prop("ranges", "", 0);
        begin("pcie@1000120000");
            prop_u32("#address-cells", 3); prop_u32("#size-cells", 2);
            begin("rp1");
                prop_u32("#address-cells", 2); prop_u32("#size-cells", 2);
                begin("serial@30000"); prop("compatible", "arm,pl011-axi", 14); prop_cells("reg", 4, rp1); prop_str("status", "disabled"); end();
            end();
        end();
    end();
    return finish();
}

/* QEMU's riscv64 virt machine, as U-Boot hands it on: the console named by its path */
static const void *virt(void)
{
    static const uint32_t reg[4] = { 0, 0x10000000u, 0, 0x100u };
    start();
    prop_u32("#address-cells", 2); prop_u32("#size-cells", 2);
    begin("chosen"); prop_str("stdout-path", "/soc/serial@10000000"); end();
    begin("soc");
        prop_u32("#address-cells", 2); prop_u32("#size-cells", 2);
        prop("ranges", "", 0);
        begin("serial@10000000"); prop_str("compatible", "ns16550a"); prop_cells("reg", 4, reg); end();
    end();
    return finish();
}

int main(int argc, char **argv)
{
    fdt_uart_t u;
    const void *b;

    if (argc == 6) {                                     /* a real blob, and what it should give */
        static unsigned char real[2 * 1024 * 1024];
        FILE *f = fopen(argv[1], "rb");
        size_t n;
        int kind = strcmp(argv[2], "pl011") == 0 ? FDT_UART_PL011 : strcmp(argv[2], "16550") == 0 ? FDT_UART_16550 : FDT_UART_NONE;
        if (!f) { printf("cannot open %s\n", argv[1]); return 2; }
        n = fread(real, 1, sizeof real, f);
        fclose(f);
        memset(&u, 0xAA, sizeof u);
        CHECK(n > 40 && fdt_console_uart(real, &u) && is(&u, kind, strtoull(argv[3], 0, 0), (uint32_t)strtoul(argv[4], 0, 0), (uint32_t)strtoul(argv[5], 0, 0)),
              "%s: %s at 0x%llx, registers %u apart (shift), %u wide", argv[1], SHOW(u));
        printf("  %s: %s at 0x%llx, shift %u, width %u\n", argv[1], SHOW(u));
        printf("  %d checks, %d failures\n", checks, failures);
        return failures != 0;
    }

    /* ---- the three boards ---- */
    b = mars("serial0:115200n8", 0, 1);
    CHECK(fdt_valid(b), "the blob the test builds is a devicetree");
    memset(&u, 0xAA, sizeof u);
    CHECK(fdt_console_uart(b, &u) && is(&u, FDT_UART_16550, 0x10000000ull, 2, 4),
          "the Mars: a 16550 at 0x10000000 with its registers four bytes apart and four wide: %s 0x%llx %u %u", SHOW(u));
    CHECK(fdt_console_uart(mars("serial0", 0, 1), &u) && is(&u, FDT_UART_16550, 0x10000000ull, 2, 4), "the same with no line settings after the alias");
    CHECK(fdt_console_uart(mars("serial0:115200n8", "okay", 1), &u) && u.kind == FDT_UART_16550, "and with status okay");

    memset(&u, 0xAA, sizeof u);
    CHECK(fdt_console_uart(pi5("arm,pl011-axi\0arm,pl011\0arm,primecell", 37), &u) && is(&u, FDT_UART_PL011, 0x107d001000ull, 0, 4),
          "the Pi 5: serial10, a PL011, its address carried through the bus's ranges to 0x107d001000: %s 0x%llx %u %u", SHOW(u));
    CHECK(fdt_console_uart(pi5("arm,pl011-axi", 14), &u) && is(&u, FDT_UART_PL011, 0x107d001000ull, 0, 4), "a node that says only arm,pl011-axi is a PL011 too");

    memset(&u, 0xAA, sizeof u);
    CHECK(fdt_console_uart(virt(), &u) && is(&u, FDT_UART_16550, 0x10000000ull, 0, 1),
          "QEMU's riscv64 machine: named by its path, a 16550 with registers a byte apart: %s 0x%llx %u %u", SHOW(u));

    /* ---- what must find nothing, and leave *out as no line ---- */
    memset(&u, 0xAA, sizeof u);
    CHECK(!fdt_console_uart(mars(0, 0, 1), &u) && u.kind == FDT_UART_NONE, "no stdout-path: no line, and it is not guessed");
    CHECK(!fdt_console_uart(mars("serial7:115200n8", 0, 1), &u) && u.kind == FDT_UART_NONE, "an alias that is not there");
    CHECK(!fdt_console_uart(mars("/soc/serial@20000000", 0, 1), &u) && u.kind == FDT_UART_NONE, "a path to no node");
    CHECK(!fdt_console_uart(mars("/soc/serial", 0, 1), &u) && u.kind == FDT_UART_NONE, "a node's name without its address is not that node");
    CHECK(!fdt_console_uart(mars("serial0:115200n8", "disabled", 1), &u) && u.kind == FDT_UART_NONE, "a UART that is disabled");
    CHECK(!fdt_console_uart(mars("serial0:115200n8", 0, 0), &u) && u.kind == FDT_UART_NONE, "a bus with no ranges: its addresses cannot be carried up");
    CHECK(!fdt_console_uart(pi5("brcm,bcm2835-aux-uart", 22), &u) && u.kind == FDT_UART_NONE, "a UART of a kind the console has no driver for");
    {
        static const uint32_t far_ranges[4] = { 0x10000000u, 0x10, 0x10000000u, 0x1000u };
        static const uint32_t reg[2] = { 0x7d001000u, 0x200u };
        start();
        prop_u32("#address-cells", 2); prop_u32("#size-cells", 2);
        begin("chosen"); prop_str("stdout-path", "/soc/serial@7d001000"); end();
        begin("soc"); prop_u32("#address-cells", 1); prop_u32("#size-cells", 1); prop_cells("ranges", 4, far_ranges);
            begin("serial@7d001000"); prop_str("compatible", "arm,pl011"); prop_cells("reg", 2, reg); end();
        end();
        CHECK(!fdt_console_uart(finish(), &u) && u.kind == FDT_UART_NONE, "an address none of the bus's ranges covers");
    }
    {
        /* the console named is behind a bus with three address cells, as the Pi 5's RP1 UARTs are: not handled, and said so */
        b = pi5("arm,pl011", 10);
        start();
        prop_u32("#address-cells", 2); prop_u32("#size-cells", 2);
        begin("chosen"); prop_str("stdout-path", "/pcie/serial@30000"); end();
        begin("pcie"); prop_u32("#address-cells", 3); prop_u32("#size-cells", 2); prop("ranges", "", 0);
            { static const uint32_t reg[5] = { 0, 0xc0, 0x40030000u, 0, 0x100 };
              begin("serial@30000"); prop_str("compatible", "arm,pl011"); prop_cells("reg", 5, reg); end(); }
        end();
        CHECK(!fdt_console_uart(finish(), &u) && u.kind == FDT_UART_NONE, "a UART behind a bus with three address cells");
    }
    memset(&u, 0xAA, sizeof u);
    CHECK(!fdt_console_uart(0, &u) && u.kind == FDT_UART_NONE, "no devicetree at all");
    b = mars("serial0:115200n8", 0, 1);
    blob[0] = 0;
    CHECK(!fdt_console_uart(b, &u) && u.kind == FDT_UART_NONE, "what is not a devicetree");
    {
        /* cut short at every length: never read past the end, never find a line in half a tree */
        unsigned n, total, found = 0;
        static unsigned char cut[8192];
        b = mars("serial0:115200n8", 0, 1);
        total = (unsigned)((blob[4] << 24) | (blob[5] << 16) | (blob[6] << 8) | blob[7]);
        for (n = 40; n < total; n += 4) {
            memcpy(cut, blob, total);
            put32(cut + 36, n > 56 ? (n - 56 < st_len ? n - 56 : st_len) : 0);      /* the structure block ends early */
            if (fdt_console_uart(cut, &u) && !is(&u, FDT_UART_16550, 0x10000000ull, 2, 4)) found++;
        }
        CHECK(found == 0, "a structure block cut short at any length gives the right line or none: %u wrong", found);
    }

    printf("  %d checks, %d failures\n", checks, failures);
    return failures != 0;
}