// SPDX-License-Identifier: GPL-2.0+
/*
 * Manage Keyboard Matrices
 *
 * Copyright (c) 2012 The Chromium OS Authors.
 * (C) Copyright 2004 DENX Software Engineering, Wolfgang Denk, wd@denx.de
 */

#include <common.h>
#include <dm.h>
#include <key_matrix.h>
#include <malloc.h>
#include <linux/input.h>

/**
 * Determine if the current keypress configuration can cause key ghosting
 *
 * We figure this out by seeing if we have two or more keys in the same
 * column, as well as two or more keys in the same row.
 *
 * @param config        Keyboard matrix config
 * @param keys          List of keys to check
 * @param valid         Number of valid keypresses to check
 * @return 0 if no ghosting is possible, 1 if it is
 */
static int has_ghosting(struct key_matrix *config, struct key_matrix_key *keys,
                        int valid)
{
        int key_in_same_col = 0, key_in_same_row = 0;
        int i, j;

        if (!config->ghost_filter || valid < 3)
                return 0;

        for (i = 0; i < valid; i++) {
                /*
                 * Find 2 keys such that one key is in the same row
                 * and the other is in the same column as the i-th key.
                 */
                for (j = i + 1; j < valid; j++) {
                        if (keys[j].col == keys[i].col)
                                key_in_same_col = 1;
                        if (keys[j].row == keys[i].row)
                                key_in_same_row = 1;
                }
        }

        if (key_in_same_col && key_in_same_row)
                return 1;
        else
                return 0;
}

int key_matrix_decode(struct key_matrix *config, struct key_matrix_key keys[],
                      int num_keys, int keycode[], int max_keycodes)
{
        const u8 *keymap;
        int valid, upto;
        int pos;

        debug("%s: num_keys = %d\n", __func__, num_keys);
        keymap = config->plain_keycode;
        for (valid = upto = 0; upto < num_keys; upto++) {
                struct key_matrix_key *key = &keys[upto];

                debug("  valid=%d, row=%d, col=%d\n", key->valid, key->row,
                      key->col);
                if (!key->valid)
                        continue;
                pos = key->row * config->num_cols + key->col;
                if (config->fn_keycode && pos == config->fn_pos)
                        keymap = config->fn_keycode;

                /* Convert the (row, col) values into a keycode */
                if (valid < max_keycodes)
                        keycode[valid++] = keymap[pos];
                debug("    keycode=%d\n", keymap[pos]);
        }

        /* For a ghost key config, ignore the keypresses for this iteration. */
        if (has_ghosting(config, keys, valid)) {
                valid = 0;
                debug("    ghosting detected!\n");
        }
        debug("  %d valid keycodes found\n", valid);

        return valid;
}

/**
 * Create a new keycode map from some provided data
 *
 * This decodes a keycode map in the format used by the fdt, which is one
 * word per entry, with the row, col and keycode encoded in that word.
 *
 * We create a (row x col) size byte array with each entry containing the
 * keycode for that (row, col). We also search for map_keycode and return
 * its position if found (this is used for finding the Fn key).
 *
 * @param config        Key matrix dimensions structure
 * @param data          Keycode data
 * @param len           Number of entries in keycode table
 * @param map_keycode   Key code to find in the map
 * @param pos           Returns position of map_keycode, if found, else -1
 * @return map  Pointer to allocated map
 */
static uchar *create_keymap(struct key_matrix *config, const u32 *data, int len,
                            int map_keycode, int *pos)
{
        uchar *map;

        if (pos)
                *pos = -1;
        map = (uchar *)calloc(1, config->key_count);
        if (!map) {
                debug("%s: failed to malloc %d bytes\n", __func__,
                        config->key_count);
                return NULL;
        }

        for (; len >= sizeof(u32); data++, len -= 4) {
                u32 tmp = fdt32_to_cpu(*data);
                int key_code, row, col;
                int entry;

                row = (tmp >> 24) & 0xff;
                col = (tmp >> 16) & 0xff;
                key_code = tmp & 0xffff;
                entry = row * config->num_cols + col;
                map[entry] = key_code;
                debug("   map %d, %d: pos=%d, keycode=%d\n", row, col,
                      entry, key_code);
                if (pos && map_keycode == key_code)
                        *pos = entry;
        }

        return map;
}

int key_matrix_decode_fdt(struct udevice *dev, struct key_matrix *config)
{
        const u32 *prop;
        int proplen;
        uchar *plain_keycode;

        prop = dev_read_prop(dev, "linux,keymap", &proplen);
        /* Basic keymap is required */
        if (!prop) {
                debug("%s: cannot find keycode-plain map\n", __func__);
                return -1;
        }

        plain_keycode = create_keymap(config, prop, proplen, KEY_FN,
                                      &config->fn_pos);
        config->plain_keycode = plain_keycode;
        /* Conversion error -> fail */
        if (!config->plain_keycode)
                return -1;

        prop = dev_read_prop(dev, "linux,fn-keymap", &proplen);
        /* fn keymap is optional */
        if (!prop)
                goto done;

        config->fn_keycode = create_keymap(config, prop, proplen, -1, NULL);
        /* Conversion error -> fail */
        if (!config->fn_keycode) {
                free(plain_keycode);
                return -1;
        }

done:
        debug("%s: Decoded key maps %p, %p from fdt\n", __func__,
              config->plain_keycode, config->fn_keycode);
        return 0;
}

int key_matrix_init(struct key_matrix *config, int rows, int cols,
                    int ghost_filter)
{
        memset(config, '\0', sizeof(*config));
        config->num_rows = rows;
        config->num_cols = cols;
        config->key_count = rows * cols;
        config->ghost_filter = ghost_filter;
        assert(config->key_count > 0);

        return 0;
}