// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright © 2019 Collabora Ltd
 */

#include <config.h>
#include <command.h>
#include <fdtdec.h>
#include <fs.h>
#include <log.h>
#include <mapmem.h>
#include <memalign.h>
#include <part.h>

struct persistent_ram_buffer {
        u32    sig;
        u32    start;
        u32    size;
        u8     data[0];
};

#define PERSISTENT_RAM_SIG (0x43474244) /* DBGC */
#define RAMOOPS_KERNMSG_HDR "===="

#define PSTORE_TYPE_DMESG 0
#define PSTORE_TYPE_CONSOLE 2
#define PSTORE_TYPE_FTRACE 3
#define PSTORE_TYPE_PMSG 7
#define PSTORE_TYPE_ALL 255

static phys_addr_t pstore_addr = CONFIG_CMD_PSTORE_MEM_ADDR;
static phys_size_t pstore_length = CONFIG_CMD_PSTORE_MEM_SIZE;
static unsigned int pstore_record_size = CONFIG_CMD_PSTORE_RECORD_SIZE;
static unsigned int pstore_console_size = CONFIG_CMD_PSTORE_CONSOLE_SIZE;
static unsigned int pstore_ftrace_size = CONFIG_CMD_PSTORE_FTRACE_SIZE;
static unsigned int pstore_pmsg_size = CONFIG_CMD_PSTORE_PMSG_SIZE;
static unsigned int pstore_ecc_size = CONFIG_CMD_PSTORE_ECC_SIZE;
static unsigned int buffer_size;

 /**
  * pstore_read_kmsg_hdr() - Check kernel header and get compression flag if
  *                          available.
  * @buffer: Kernel messages buffer.
  * @compressed: Returns TRUE if kernel buffer is compressed, else FALSE.
  *
  * Check if buffer starts with a kernel header of the form:
  *   ====<secs>.<nsecs>[-<compression>]\n
  * If <compression> is equal to 'C' then the buffer is compressed, else iter
  * should be 'D'.
  *
  * Return: Length of kernel header.
  */
static int pstore_read_kmsg_hdr(char *buffer, bool *compressed)
{
        char *ptr = buffer;
        *compressed = false;

        if (strncmp(RAMOOPS_KERNMSG_HDR, ptr, strlen(RAMOOPS_KERNMSG_HDR)) != 0)
                return 0;

        ptr += strlen(RAMOOPS_KERNMSG_HDR);

        ptr = strchr(ptr, '\n');
        if (!ptr)
                return 0;

        if (ptr[-2] == '-' && ptr[-1] == 'C')
                *compressed = true;

        return ptr - buffer + 1;
}

/**
 * pstore_get_buffer() - Get unwrapped record buffer
 * @sig: Signature to check
 * @buffer: Buffer containing wrapped record
 * @size: wrapped record size
 * @dest: Buffer used to store unwrapped record
 *
 * The record starts with <signature><start><size> header.
 * The signature is 'DBGC' for all records except for Ftrace's record(s) wich
 * use LINUX_VERSION_CODE ^ 'DBGC'.
 * Use 0 for @sig to prevent checking signature.
 * Start and size are 4 bytes long.
 *
 * Return: record's length
 */
static u32 pstore_get_buffer(u32 sig, phys_addr_t buffer, u32 size, char *dest)
{
        struct persistent_ram_buffer *prb =
                (struct persistent_ram_buffer *)map_sysmem(buffer, size);
        u32 dest_size;

        if (sig == 0 || prb->sig == sig) {
                if (prb->size == 0) {
                        log_debug("found existing empty buffer\n");
                        return 0;
                }

                if (prb->size > size) {
                        log_debug("found existing invalid buffer, size %u, start %u\n",
                                  prb->size, prb->start);
                        return 0;
                }
        } else {
                log_debug("no valid data in buffer (sig = 0x%08x)\n", prb->sig);
                return 0;
        }

        log_debug("found existing buffer, size %u, start %u\n",
                  prb->size, prb->start);

        memcpy(dest, &prb->data[prb->start], prb->size - prb->start);
        memcpy(dest + prb->size - prb->start, &prb->data[0], prb->start);

        dest_size = prb->size;
        unmap_sysmem(prb);

        return dest_size;
}

/**
 * pstore_init_buffer_size() - Init buffer size to largest record size
 *
 * Records, console, FTrace and user logs can use different buffer sizes.
 * This function allows to retrieve the biggest one.
 */
static void pstore_init_buffer_size(void)
{
        if (pstore_record_size > buffer_size)
                buffer_size = pstore_record_size;

        if (pstore_console_size > buffer_size)
                buffer_size = pstore_console_size;

        if (pstore_ftrace_size > buffer_size)
                buffer_size = pstore_ftrace_size;

        if (pstore_pmsg_size > buffer_size)
                buffer_size = pstore_pmsg_size;
}

/**
 * pstore_set() - Initialize PStore settings from command line arguments
 * @cmdtp: Command data struct pointer
 * @flag: Command flag
 * @argc: Command-line argument count
 * @argv: Array of command-line arguments
 *
 * Set pstore reserved memory info, starting at 'addr' for 'len' bytes.
 * Default length for records is 4K.
 * Mandatory arguments:
 * - addr: ramoops starting address
 * - len: ramoops total length
 * Optional arguments:
 * - record-size: size of one panic or oops record ('dump' type)
 * - console-size: size of the kernel logs record
 * - ftrace-size: size of the ftrace record(s), this can be a single record or
 *                divided in parts based on number of CPUs
 * - pmsg-size: size of the user space logs record
 * - ecc-size: enables/disables ECC support and specifies ECC buffer size in
 *             bytes (0 disables it, 1 is a special value, means 16 bytes ECC)
 *
 * Return: zero on success, CMD_RET_USAGE in case of misuse and negative
 * on error.
 */
static int pstore_set(struct cmd_tbl *cmdtp, int flag,  int argc,
                      char * const argv[])
{
        if (argc < 3)
                return CMD_RET_USAGE;

        /* Address is specified since argc > 2
         */
        pstore_addr = hextoul(argv[1], NULL);

        /* Length is specified since argc > 2
         */
        pstore_length = hextoul(argv[2], NULL);

        if (argc > 3)
                pstore_record_size = hextoul(argv[3], NULL);

        if (argc > 4)
                pstore_console_size = hextoul(argv[4], NULL);

        if (argc > 5)
                pstore_ftrace_size = hextoul(argv[5], NULL);

        if (argc > 6)
                pstore_pmsg_size = hextoul(argv[6], NULL);

        if (argc > 7)
                pstore_ecc_size = hextoul(argv[7], NULL);

        if (pstore_length < (pstore_record_size + pstore_console_size
                             + pstore_ftrace_size + pstore_pmsg_size)) {
                printf("pstore <len> should be larger than the sum of all records sizes\n");
                pstore_length = 0;
        }

        log_debug("pstore set done: start 0x%08llx - length 0x%llx\n",
                  (unsigned long long)pstore_addr,
                  (unsigned long long)pstore_length);

        return 0;
}

/**
 * pstore_print_buffer() - Print buffer
 * @type: buffer type
 * @buffer: buffer to print
 * @size: buffer size
 *
 * Print buffer type and content
 */
static void pstore_print_buffer(char *type, char *buffer, u32 size)
{
        u32 i = 0;

        printf("**** %s\n", type);
        while (i < size && buffer[i] != 0) {
                putc(buffer[i]);
                i++;
        }
}

/**
 * pstore_display() - Display existing records in pstore reserved memory
 * @cmdtp: Command data struct pointer
 * @flag: Command flag
 * @argc: Command-line argument count
 * @argv: Array of command-line arguments
 *
 * A 'record-type' can be given to only display records of this kind.
 * If no 'record-type' is given, all valid records are dispayed.
 * 'record-type' can be one of 'dump', 'console', 'ftrace' or 'user'. For 'dump'
 * and 'ftrace' types, a 'nb' can be given to only display one record.
 *
 * Return: zero on success, CMD_RET_USAGE in case of misuse and negative
 * on error.
 */
static int pstore_display(struct cmd_tbl *cmdtp, int flag,  int argc,
                          char * const argv[])
{
        int type = PSTORE_TYPE_ALL;
        phys_addr_t ptr;
        char *buffer;
        u32 size;
        int header_len = 0;
        bool compressed;

        if (argc > 1) {
                if (!strcmp(argv[1], "dump"))
                        type = PSTORE_TYPE_DMESG;
                else if (!strcmp(argv[1], "console"))
                        type = PSTORE_TYPE_CONSOLE;
                else if (!strcmp(argv[1], "ftrace"))
                        type = PSTORE_TYPE_FTRACE;
                else if (!strcmp(argv[1], "user"))
                        type = PSTORE_TYPE_PMSG;
                else
                        return CMD_RET_USAGE;
        }

        if (pstore_length == 0) {
                printf("Please set PStore configuration\n");
                return CMD_RET_USAGE;
        }

        if (buffer_size == 0)
                pstore_init_buffer_size();

        buffer = malloc_cache_aligned(buffer_size);

        if (type == PSTORE_TYPE_DMESG || type == PSTORE_TYPE_ALL) {
                ptr = pstore_addr;
                phys_addr_t ptr_end = ptr + pstore_length - pstore_pmsg_size
                                - pstore_ftrace_size - pstore_console_size;

                if (argc > 2) {
                        ptr += dectoul(argv[2], NULL)
                                * pstore_record_size;
                        ptr_end = ptr + pstore_record_size;
                }

                while (ptr < ptr_end) {
                        size = pstore_get_buffer(PERSISTENT_RAM_SIG, ptr,
                                                 pstore_record_size, buffer);
                        ptr += pstore_record_size;

                        if (size == 0)
                                continue;

                        header_len = pstore_read_kmsg_hdr(buffer, &compressed);
                        if (header_len == 0) {
                                log_debug("no valid kernel header\n");
                                continue;
                        }

                        if (compressed) {
                                printf("Compressed buffer, display not available\n");
                                continue;
                        }

                        pstore_print_buffer("Dump", buffer + header_len,
                                            size - header_len);
                }
        }

        if (type == PSTORE_TYPE_CONSOLE || type == PSTORE_TYPE_ALL) {
                ptr = pstore_addr + pstore_length - pstore_pmsg_size
                        - pstore_ftrace_size - pstore_console_size;
                size = pstore_get_buffer(PERSISTENT_RAM_SIG, ptr,
                                         pstore_console_size, buffer);
                if (size != 0)
                        pstore_print_buffer("Console", buffer, size);
        }

        if (type == PSTORE_TYPE_FTRACE || type == PSTORE_TYPE_ALL) {
                ptr = pstore_addr + pstore_length - pstore_pmsg_size
                - pstore_ftrace_size;
                /* The FTrace record(s) uses LINUX_VERSION_CODE ^ 'DBGC'
                 * signature, pass 0 to pstore_get_buffer to prevent
                 * checking it
                 */
                size = pstore_get_buffer(0, ptr, pstore_ftrace_size, buffer);
                if (size != 0)
                        pstore_print_buffer("FTrace", buffer, size);
        }

        if (type == PSTORE_TYPE_PMSG || type == PSTORE_TYPE_ALL) {
                ptr = pstore_addr + pstore_length - pstore_pmsg_size;
                size = pstore_get_buffer(PERSISTENT_RAM_SIG, ptr,
                                         pstore_pmsg_size, buffer);
                if (size != 0)
                        pstore_print_buffer("User", buffer, size);
        }

        free(buffer);

        return 0;
}

/**
 * pstore_save() - Save existing records from pstore reserved memory
 * @cmdtp: Command data struct pointer
 * @flag: Command flag
 * @argc: Command-line argument count
 * @argv: Array of command-line arguments
 *
 * the records are saved under 'directory path', which should already exist,
 * to partition 'part' on device type 'interface' instance 'dev'
 * Filenames are automatically generated, depending on record type, like in
 * /sys/fs/pstore under Linux
 *
 * Return: zero on success, CMD_RET_USAGE in case of misuse and negative
 * on error.
 */
static int pstore_save(struct cmd_tbl *cmdtp, int flag,  int argc,
                       char * const argv[])
{
        phys_addr_t ptr, ptr_end;
        char *buffer;
        char *save_argv[6];
        char addr[19], length[19];
        char path[256];
        u32 size;
        unsigned int index;
        int header_len = 0;
        bool compressed;

        if (argc < 4)
                return CMD_RET_USAGE;

        if (pstore_length == 0) {
                printf("Please set PStore configuration\n");
                return CMD_RET_USAGE;
        }

        if (buffer_size == 0)
                pstore_init_buffer_size();

        buffer = malloc_cache_aligned(buffer_size);
        sprintf(addr, "0x%p", buffer);

        save_argv[0] = argv[0];
        save_argv[1] = argv[1];
        save_argv[2] = argv[2];
        save_argv[3] = addr;
        save_argv[4] = path;
        save_argv[5] = length;

        /* Save all Dump records */
        ptr = pstore_addr;
        ptr_end = ptr + pstore_length - pstore_pmsg_size - pstore_ftrace_size
                                - pstore_console_size;
        index = 0;
        while (ptr < ptr_end) {
                size = pstore_get_buffer(PERSISTENT_RAM_SIG, ptr,
                                         pstore_record_size, buffer);
                ptr += pstore_record_size;

                if (size == 0)
                        continue;

                header_len = pstore_read_kmsg_hdr(buffer, &compressed);
                if (header_len == 0) {
                        log_debug("no valid kernel header\n");
                        continue;
                }

                sprintf(addr, "0x%08lx", (ulong)map_to_sysmem(buffer + header_len));
                sprintf(length, "0x%X", size - header_len);
                sprintf(path, "%s/dmesg-ramoops-%u%s", argv[3], index,
                        compressed ? ".enc.z" : "");
                do_save(cmdtp, flag, 6, save_argv, FS_TYPE_ANY);
                index++;
        }

        sprintf(addr, "0x%08lx", (ulong)map_to_sysmem(buffer));

        /* Save Console record */
        size = pstore_get_buffer(PERSISTENT_RAM_SIG, ptr, pstore_console_size,
                                 buffer);
        if (size != 0) {
                sprintf(length, "0x%X", size);
                sprintf(path, "%s/console-ramoops-0", argv[3]);
                do_save(cmdtp, flag, 6, save_argv, FS_TYPE_ANY);
        }
        ptr += pstore_console_size;

        /* Save FTrace record(s)
         * The FTrace record(s) uses LINUX_VERSION_CODE ^ 'DBGC' signature,
         * pass 0 to pstore_get_buffer to prevent checking it
         */
        size = pstore_get_buffer(0, ptr, pstore_ftrace_size, buffer);
        if (size != 0) {
                sprintf(length, "0x%X", size);
                sprintf(path, "%s/ftrace-ramoops-0", argv[3]);
                do_save(cmdtp, flag, 6, save_argv, FS_TYPE_ANY);
        }
        ptr += pstore_ftrace_size;

        /* Save Console record */
        size = pstore_get_buffer(PERSISTENT_RAM_SIG, ptr, pstore_pmsg_size,
                                 buffer);
        if (size != 0) {
                sprintf(length, "0x%X", size);
                sprintf(path, "%s/pmsg-ramoops-0", argv[3]);
                do_save(cmdtp, flag, 6, save_argv, FS_TYPE_ANY);
        }

        free(buffer);

        return 0;
}

static struct cmd_tbl cmd_pstore_sub[] = {
        U_BOOT_CMD_MKENT(set, 8, 0, pstore_set, "", ""),
        U_BOOT_CMD_MKENT(display, 3, 0, pstore_display, "", ""),
        U_BOOT_CMD_MKENT(save, 4, 0, pstore_save, "", ""),
};

static int do_pstore(struct cmd_tbl *cmdtp, int flag, int argc, char * const argv[])
{
        struct cmd_tbl *c;

        if (argc < 2)
                return CMD_RET_USAGE;

        /* Strip off leading argument */
        argc--;
        argv++;

        c = find_cmd_tbl(argv[0], cmd_pstore_sub, ARRAY_SIZE(cmd_pstore_sub));

        if (!c)
                return CMD_RET_USAGE;

        return c->cmd(cmdtp, flag, argc, argv);
}

void fdt_fixup_pstore(void *blob)
{
        char node[32];
        int  nodeoffset;        /* node offset from libfdt */

        nodeoffset = fdt_path_offset(blob, "/");
        if (nodeoffset < 0) {
                /* Not found or something else bad happened. */
                log_err("fdt_path_offset() returned %s\n", fdt_strerror(nodeoffset));
                return;
        }

        nodeoffset = fdt_add_subnode(blob, nodeoffset, "reserved-memory");
        if (nodeoffset < 0) {
                log_err("Add 'reserved-memory' node failed: %s\n",
                                fdt_strerror(nodeoffset));
                return;
        }
        fdt_setprop_u32(blob, nodeoffset, "#address-cells", 2);
        fdt_setprop_u32(blob, nodeoffset, "#size-cells", 2);
        fdt_setprop_empty(blob, nodeoffset, "ranges");

        sprintf(node, "ramoops@%llx", (unsigned long long)pstore_addr);
        nodeoffset = fdt_add_subnode(blob, nodeoffset, node);
        if (nodeoffset < 0) {
                log_err("Add '%s' node failed: %s\n", node, fdt_strerror(nodeoffset));
                return;
        }
        fdt_setprop_string(blob, nodeoffset, "compatible", "ramoops");
        fdt_setprop_u64(blob, nodeoffset, "reg", pstore_addr);
        fdt_appendprop_u64(blob, nodeoffset, "reg", pstore_length);
        fdt_setprop_u32(blob, nodeoffset, "record-size", pstore_record_size);
        fdt_setprop_u32(blob, nodeoffset, "console-size", pstore_console_size);
        fdt_setprop_u32(blob, nodeoffset, "ftrace-size", pstore_ftrace_size);
        fdt_setprop_u32(blob, nodeoffset, "pmsg-size", pstore_pmsg_size);
        fdt_setprop_u32(blob, nodeoffset, "ecc-size", pstore_ecc_size);
}

U_BOOT_CMD(pstore, 10, 0, do_pstore,
           "Manage Linux Persistent Storage",
           "set <addr> <len> [record-size] [console-size] [ftrace-size] [pmsg_size] [ecc-size]\n"
           "- Set pstore reserved memory info, starting at 'addr' for 'len' bytes.\n"
           "  Default length for records is 4K.\n"
           "  'record-size' is the size of one panic or oops record ('dump' type).\n"
           "  'console-size' is the size of the kernel logs record.\n"
           "  'ftrace-size' is the size of the ftrace record(s), this can be a single\n"
           "  record or divided in parts based on number of CPUs.\n"
           "  'pmsg-size' is the size of the user space logs record.\n"
           "  'ecc-size' enables/disables ECC support and specifies ECC buffer size in\n"
           "  bytes (0 disables it, 1 is a special value, means 16 bytes ECC).\n"
           "pstore display [record-type] [nb]\n"
           "- Display existing records in pstore reserved memory. A 'record-type' can\n"
           "  be given to only display records of this kind. 'record-type' can be one\n"
           "  of 'dump', 'console', 'ftrace' or 'user'. For 'dump' and 'ftrace' types,\n"
           "  a 'nb' can be given to only display one record.\n"
           "pstore save <interface> <dev[:part]> <directory-path>\n"
           "- Save existing records in pstore reserved memory under 'directory path'\n"
           "  to partition 'part' on device type 'interface' instance 'dev'.\n"
           "  Filenames are automatically generated, depending on record type, like\n"
           "  in /sys/fs/pstore under Linux.\n"
           "  The 'directory-path' should already exist.\n"
);