/*
 * Chromium OS cros_ec driver - sandbox emulation
 *
 * Copyright (c) 2013 The Chromium OS Authors.
 *
 * SPDX-License-Identifier:     GPL-2.0+
 */

#include <common.h>
#include <cros_ec.h>
#include <dm.h>
#include <ec_commands.h>
#include <errno.h>
#include <hash.h>
#include <malloc.h>
#include <os.h>
#include <u-boot/sha256.h>
#include <spi.h>
#include <asm/state.h>
#include <asm/sdl.h>
#include <linux/input.h>

/*
 * Ultimately it shold be possible to connect an Chrome OS EC emulation
 * to U-Boot and remove all of this code. But this provides a test
 * environment for bringing up chromeos_sandbox and demonstrating its
 * utility.
 *
 * This emulation includes the following:
 *
 * 1. Emulation of the keyboard, by converting keypresses received from SDL
 * into key scan data, passed back from the EC as key scan messages. The
 * key layout is read from the device tree.
 *
 * 2. Emulation of vboot context - so this can be read/written as required.
 *
 * 3. Save/restore of EC state, so that the vboot context, flash memory
 * contents and current image can be preserved across boots. This is important
 * since the EC is supposed to continue running even if the AP resets.
 *
 * 4. Some event support, in particular allowing Escape to be pressed on boot
 * to enter recovery mode. The EC passes this to U-Boot through the normal
 * event message.
 *
 * 5. Flash read/write/erase support, so that software sync works. The
 * protect messages are supported but no protection is implemented.
 *
 * 6. Hashing of the EC image, again to support software sync.
 *
 * Other features can be added, although a better path is probably to link
 * the EC image in with U-Boot (Vic has demonstrated a prototype for this).
 */

DECLARE_GLOBAL_DATA_PTR;

#define KEYBOARD_ROWS   8
#define KEYBOARD_COLS   13

/* A single entry of the key matrix */
struct ec_keymatrix_entry {
        int row;        /* key matrix row */
        int col;        /* key matrix column */
        int keycode;    /* corresponding linux key code */
};

/**
 * struct ec_state - Information about the EC state
 *
 * @vbnv_context: Vboot context data stored by EC
 * @ec_config: FDT config information about the EC (e.g. flashmap)
 * @flash_data: Contents of flash memory
 * @flash_data_len: Size of flash memory
 * @current_image: Current image the EC is running
 * @matrix_count: Number of keys to decode in matrix
 * @matrix: Information about keyboard matrix
 * @keyscan: Current keyscan information (bit set for each row/column pressed)
 * @recovery_req: Keyboard recovery requested
 */
struct ec_state {
        uint8_t vbnv_context[EC_VBNV_BLOCK_SIZE];
        struct fdt_cros_ec ec_config;
        uint8_t *flash_data;
        int flash_data_len;
        enum ec_current_image current_image;
        int matrix_count;
        struct ec_keymatrix_entry *matrix;      /* the key matrix info */
        uint8_t keyscan[KEYBOARD_COLS];
        bool recovery_req;
} s_state, *g_state;

/**
 * cros_ec_read_state() - read the sandbox EC state from the state file
 *
 * If data is available, then blob and node will provide access to it. If
 * not this function sets up an empty EC.
 *
 * @param blob: Pointer to device tree blob, or NULL if no data to read
 * @param node: Node offset to read from
 */
static int cros_ec_read_state(const void *blob, int node)
{
        struct ec_state *ec = &s_state;
        const char *prop;
        int len;

        /* Set everything to defaults */
        ec->current_image = EC_IMAGE_RO;
        if (!blob)
                return 0;

        /* Read the data if available */
        ec->current_image = fdtdec_get_int(blob, node, "current-image",
                                           EC_IMAGE_RO);
        prop = fdt_getprop(blob, node, "vbnv-context", &len);
        if (prop && len == sizeof(ec->vbnv_context))
                memcpy(ec->vbnv_context, prop, len);

        prop = fdt_getprop(blob, node, "flash-data", &len);
        if (prop) {
                ec->flash_data_len = len;
                ec->flash_data = os_malloc(len);
                if (!ec->flash_data)
                        return -ENOMEM;
                memcpy(ec->flash_data, prop, len);
                debug("%s: Loaded EC flash data size %#x\n", __func__, len);
        }

        return 0;
}

/**
 * cros_ec_write_state() - Write out our state to the state file
 *
 * The caller will ensure that there is a node ready for the state. The node
 * may already contain the old state, in which case it is overridden.
 *
 * @param blob: Device tree blob holding state
 * @param node: Node to write our state into
 */
static int cros_ec_write_state(void *blob, int node)
{
        struct ec_state *ec = g_state;

        /* We are guaranteed enough space to write basic properties */
        fdt_setprop_u32(blob, node, "current-image", ec->current_image);
        fdt_setprop(blob, node, "vbnv-context", ec->vbnv_context,
                    sizeof(ec->vbnv_context));
        return state_setprop(node, "flash-data", ec->flash_data,
                             ec->ec_config.flash.length);
}

SANDBOX_STATE_IO(cros_ec, "google,cros-ec", cros_ec_read_state,
                 cros_ec_write_state);

/**
 * Return the number of bytes used in the specified image.
 *
 * This is the actual size of code+data in the image, as opposed to the
 * amount of space reserved in flash for that image. This code is similar to
 * that used by the real EC code base.
 *
 * @param ec    Current emulated EC state
 * @param entry Flash map entry containing the image to check
 * @return actual image size in bytes, 0 if the image contains no content or
 * error.
 */
static int get_image_used(struct ec_state *ec, struct fmap_entry *entry)
{
        int size;

        /*
         * Scan backwards looking for 0xea byte, which is by definition the
         * last byte of the image.  See ec.lds.S for how this is inserted at
         * the end of the image.
         */
        for (size = entry->length - 1;
             size > 0 && ec->flash_data[entry->offset + size] != 0xea;
             size--)
                ;

        return size ? size + 1 : 0;  /* 0xea byte IS part of the image */
}

/**
 * Read the key matrix from the device tree
 *
 * Keymap entries in the fdt take the form of 0xRRCCKKKK where
 * RR=Row CC=Column KKKK=Key Code
 *
 * @param ec    Current emulated EC state
 * @param node  Keyboard node of device tree containing keyscan information
 * @return 0 if ok, -1 on error
 */
static int keyscan_read_fdt_matrix(struct ec_state *ec, ofnode node)
{
        const u32 *cell;
        int upto;
        int len;

        cell = ofnode_get_property(node, "linux,keymap", &len);
        ec->matrix_count = len / 4;
        ec->matrix = calloc(ec->matrix_count, sizeof(*ec->matrix));
        if (!ec->matrix) {
                debug("%s: Out of memory for key matrix\n", __func__);
                return -1;
        }

        /* Now read the data */
        for (upto = 0; upto < ec->matrix_count; upto++) {
                struct ec_keymatrix_entry *matrix = &ec->matrix[upto];
                u32 word;

                word = fdt32_to_cpu(*cell++);
                matrix->row = word >> 24;
                matrix->col = (word >> 16) & 0xff;
                matrix->keycode = word & 0xffff;

                /* Hard-code some sanity limits for now */
                if (matrix->row >= KEYBOARD_ROWS ||
                    matrix->col >= KEYBOARD_COLS) {
                        debug("%s: Matrix pos out of range (%d,%d)\n",
                              __func__, matrix->row, matrix->col);
                        return -1;
                }
        }

        if (upto != ec->matrix_count) {
                debug("%s: Read mismatch from key matrix\n", __func__);
                return -1;
        }

        return 0;
}

/**
 * Return the next keyscan message contents
 *
 * @param ec    Current emulated EC state
 * @param scan  Place to put keyscan bytes for the keyscan message (must hold
 *              enough space for a full keyscan)
 * @return number of bytes of valid scan data
 */
static int cros_ec_keyscan(struct ec_state *ec, uint8_t *scan)
{
        const struct ec_keymatrix_entry *matrix;
        int bytes = KEYBOARD_COLS;
        int key[8];     /* allow up to 8 keys to be pressed at once */
        int count;
        int i;

        memset(ec->keyscan, '\0', bytes);
        count = sandbox_sdl_scan_keys(key, ARRAY_SIZE(key));

        /* Look up keycode in matrix */
        for (i = 0, matrix = ec->matrix; i < ec->matrix_count; i++, matrix++) {
                bool found;
                int j;

                for (found = false, j = 0; j < count; j++) {
                        if (matrix->keycode == key[j])
                                found = true;
                }

                if (found) {
                        debug("%d: %d,%d\n", matrix->keycode, matrix->row,
                              matrix->col);
                        ec->keyscan[matrix->col] |= 1 << matrix->row;
                }
        }

        memcpy(scan, ec->keyscan, bytes);
        return bytes;
}

/**
 * Process an emulated EC command
 *
 * @param ec            Current emulated EC state
 * @param req_hdr       Pointer to request header
 * @param req_data      Pointer to body of request
 * @param resp_hdr      Pointer to place to put response header
 * @param resp_data     Pointer to place to put response data, if any
 * @return length of response data, or 0 for no response data, or -1 on error
 */
static int process_cmd(struct ec_state *ec,
                       struct ec_host_request *req_hdr, const void *req_data,
                       struct ec_host_response *resp_hdr, void *resp_data)
{
        int len;

        /* TODO(sjg@chromium.org): Check checksums */
        debug("EC command %#0x\n", req_hdr->command);

        switch (req_hdr->command) {
        case EC_CMD_HELLO: {
                const struct ec_params_hello *req = req_data;
                struct ec_response_hello *resp = resp_data;

                resp->out_data = req->in_data + 0x01020304;
                len = sizeof(*resp);
                break;
        }
        case EC_CMD_GET_VERSION: {
                struct ec_response_get_version *resp = resp_data;

                strcpy(resp->version_string_ro, "sandbox_ro");
                strcpy(resp->version_string_rw, "sandbox_rw");
                resp->current_image = ec->current_image;
                debug("Current image %d\n", resp->current_image);
                len = sizeof(*resp);
                break;
        }
        case EC_CMD_VBNV_CONTEXT: {
                const struct ec_params_vbnvcontext *req = req_data;
                struct ec_response_vbnvcontext *resp = resp_data;

                switch (req->op) {
                case EC_VBNV_CONTEXT_OP_READ:
                        memcpy(resp->block, ec->vbnv_context,
                               sizeof(resp->block));
                        len = sizeof(*resp);
                        break;
                case EC_VBNV_CONTEXT_OP_WRITE:
                        memcpy(ec->vbnv_context, resp->block,
                               sizeof(resp->block));
                        len = 0;
                        break;
                default:
                        printf("   ** Unknown vbnv_context command %#02x\n",
                               req->op);
                        return -1;
                }
                break;
        }
        case EC_CMD_REBOOT_EC: {
                const struct ec_params_reboot_ec *req = req_data;

                printf("Request reboot type %d\n", req->cmd);
                switch (req->cmd) {
                case EC_REBOOT_DISABLE_JUMP:
                        len = 0;
                        break;
                case EC_REBOOT_JUMP_RW:
                        ec->current_image = EC_IMAGE_RW;
                        len = 0;
                        break;
                default:
                        puts("   ** Unknown type");
                        return -1;
                }
                break;
        }
        case EC_CMD_HOST_EVENT_GET_B: {
                struct ec_response_host_event_mask *resp = resp_data;

                resp->mask = 0;
                if (ec->recovery_req) {
                        resp->mask |= EC_HOST_EVENT_MASK(
                                        EC_HOST_EVENT_KEYBOARD_RECOVERY);
                }

                len = sizeof(*resp);
                break;
        }
        case EC_CMD_VBOOT_HASH: {
                const struct ec_params_vboot_hash *req = req_data;
                struct ec_response_vboot_hash *resp = resp_data;
                struct fmap_entry *entry;
                int ret, size;

                entry = &ec->ec_config.region[EC_FLASH_REGION_RW];

                switch (req->cmd) {
                case EC_VBOOT_HASH_RECALC:
                case EC_VBOOT_HASH_GET:
                        size = SHA256_SUM_LEN;
                        len = get_image_used(ec, entry);
                        ret = hash_block("sha256",
                                         ec->flash_data + entry->offset,
                                         len, resp->hash_digest, &size);
                        if (ret) {
                                printf("   ** hash_block() failed\n");
                                return -1;
                        }
                        resp->status = EC_VBOOT_HASH_STATUS_DONE;
                        resp->hash_type = EC_VBOOT_HASH_TYPE_SHA256;
                        resp->digest_size = size;
                        resp->reserved0 = 0;
                        resp->offset = entry->offset;
                        resp->size = len;
                        len = sizeof(*resp);
                        break;
                default:
                        printf("   ** EC_CMD_VBOOT_HASH: Unknown command %d\n",
                               req->cmd);
                        return -1;
                }
                break;
        }
        case EC_CMD_FLASH_PROTECT: {
                const struct ec_params_flash_protect *req = req_data;
                struct ec_response_flash_protect *resp = resp_data;
                uint32_t expect = EC_FLASH_PROTECT_ALL_NOW |
                                EC_FLASH_PROTECT_ALL_AT_BOOT;

                printf("mask=%#x, flags=%#x\n", req->mask, req->flags);
                if (req->flags == expect || req->flags == 0) {
                        resp->flags = req->flags ? EC_FLASH_PROTECT_ALL_NOW :
                                                                0;
                        resp->valid_flags = EC_FLASH_PROTECT_ALL_NOW;
                        resp->writable_flags = 0;
                        len = sizeof(*resp);
                } else {
                        puts("   ** unexpected flash protect request\n");
                        return -1;
                }
                break;
        }
        case EC_CMD_FLASH_REGION_INFO: {
                const struct ec_params_flash_region_info *req = req_data;
                struct ec_response_flash_region_info *resp = resp_data;
                struct fmap_entry *entry;

                switch (req->region) {
                case EC_FLASH_REGION_RO:
                case EC_FLASH_REGION_RW:
                case EC_FLASH_REGION_WP_RO:
                        entry = &ec->ec_config.region[req->region];
                        resp->offset = entry->offset;
                        resp->size = entry->length;
                        len = sizeof(*resp);
                        printf("EC flash region %d: offset=%#x, size=%#x\n",
                               req->region, resp->offset, resp->size);
                        break;
                default:
                        printf("** Unknown flash region %d\n", req->region);
                        return -1;
                }
                break;
        }
        case EC_CMD_FLASH_ERASE: {
                const struct ec_params_flash_erase *req = req_data;

                memset(ec->flash_data + req->offset,
                       ec->ec_config.flash_erase_value,
                       req->size);
                len = 0;
                break;
        }
        case EC_CMD_FLASH_WRITE: {
                const struct ec_params_flash_write *req = req_data;

                memcpy(ec->flash_data + req->offset, req + 1, req->size);
                len = 0;
                break;
        }
        case EC_CMD_MKBP_STATE:
                len = cros_ec_keyscan(ec, resp_data);
                break;
        case EC_CMD_ENTERING_MODE:
                len = 0;
                break;
        default:
                printf("   ** Unknown EC command %#02x\n", req_hdr->command);
                return -1;
        }

        return len;
}

int cros_ec_sandbox_packet(struct udevice *udev, int out_bytes, int in_bytes)
{
        struct cros_ec_dev *dev = dev_get_uclass_priv(udev);
        struct ec_state *ec = dev_get_priv(dev->dev);
        struct ec_host_request *req_hdr = (struct ec_host_request *)dev->dout;
        const void *req_data = req_hdr + 1;
        struct ec_host_response *resp_hdr = (struct ec_host_response *)dev->din;
        void *resp_data = resp_hdr + 1;
        int len;

        len = process_cmd(ec, req_hdr, req_data, resp_hdr, resp_data);
        if (len < 0)
                return len;

        resp_hdr->struct_version = 3;
        resp_hdr->result = EC_RES_SUCCESS;
        resp_hdr->data_len = len;
        resp_hdr->reserved = 0;
        len += sizeof(*resp_hdr);
        resp_hdr->checksum = 0;
        resp_hdr->checksum = (uint8_t)
                -cros_ec_calc_checksum((const uint8_t *)resp_hdr, len);

        return in_bytes;
}

void cros_ec_check_keyboard(struct cros_ec_dev *dev)
{
        struct ec_state *ec = dev_get_priv(dev->dev);
        ulong start;

        printf("Press keys for EC to detect on reset (ESC=recovery)...");
        start = get_timer(0);
        while (get_timer(start) < 1000)
                ;
        putc('\n');
        if (!sandbox_sdl_key_pressed(KEY_ESC)) {
                ec->recovery_req = true;
                printf("   - EC requests recovery\n");
        }
}

int cros_ec_probe(struct udevice *dev)
{
        struct ec_state *ec = dev->priv;
        struct cros_ec_dev *cdev = dev->uclass_priv;
        struct udevice *keyb_dev;
        ofnode node;
        int err;

        memcpy(ec, &s_state, sizeof(*ec));
        err = cros_ec_decode_ec_flash(dev, &ec->ec_config);
        if (err) {
                debug("%s: Cannot device EC flash\n", __func__);
                return err;
        }

        node = ofnode_null();
        for (device_find_first_child(dev, &keyb_dev);
             keyb_dev;
             device_find_next_child(&keyb_dev)) {
                if (device_get_uclass_id(keyb_dev) == UCLASS_KEYBOARD) {
                        node = dev_ofnode(keyb_dev);
                        break;
                }
        }
        if (!ofnode_valid(node)) {
                debug("%s: No cros_ec keyboard found\n", __func__);
        } else if (keyscan_read_fdt_matrix(ec, node)) {
                debug("%s: Could not read key matrix\n", __func__);
                return -1;
        }

        /* If we loaded EC data, check that the length matches */
        if (ec->flash_data &&
            ec->flash_data_len != ec->ec_config.flash.length) {
                printf("EC data length is %x, expected %x, discarding data\n",
                       ec->flash_data_len, ec->ec_config.flash.length);
                os_free(ec->flash_data);
                ec->flash_data = NULL;
        }

        /* Otherwise allocate the memory */
        if (!ec->flash_data) {
                ec->flash_data_len = ec->ec_config.flash.length;
                ec->flash_data = os_malloc(ec->flash_data_len);
                if (!ec->flash_data)
                        return -ENOMEM;
        }

        cdev->dev = dev;
        g_state = ec;
        return cros_ec_register(dev);
}

struct dm_cros_ec_ops cros_ec_ops = {
        .packet = cros_ec_sandbox_packet,
};

static const struct udevice_id cros_ec_ids[] = {
        { .compatible = "google,cros-ec-sandbox" },
        { }
};

U_BOOT_DRIVER(cros_ec_sandbox) = {
        .name           = "cros_ec_sandbox",
        .id             = UCLASS_CROS_EC,
        .of_match       = cros_ec_ids,
        .probe          = cros_ec_probe,
        .priv_auto_alloc_size = sizeof(struct ec_state),
        .ops            = &cros_ec_ops,
};