// SPDX-License-Identifier: GPL-2.0
/*
 * Routines common to all CFI-type probes.
 * (C) 2001-2003 Red Hat, Inc.
 */

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/map.h>
#include <linux/mtd/cfi.h>
#include <linux/mtd/gen_probe.h>

static struct mtd_info *check_cmd_set(struct map_info *, int);
static struct cfi_private *genprobe_ident_chips(struct map_info *map,
                                                struct chip_probe *cp);
static int genprobe_new_chip(struct map_info *map, struct chip_probe *cp,
                             struct cfi_private *cfi);

struct mtd_info *mtd_do_chip_probe(struct map_info *map, struct chip_probe *cp)
{
        struct mtd_info *mtd;
        struct cfi_private *cfi;

        /* First probe the map to see if we have CFI stuff there. */
        cfi = genprobe_ident_chips(map, cp);

        if (!cfi)
                return NULL;

        map->fldrv_priv = cfi;
        /* OK we liked it. Now find a driver for the command set it talks */

        mtd = check_cmd_set(map, 1); /* First the primary cmdset */
        if (!mtd)
                mtd = check_cmd_set(map, 0); /* Then the secondary */

        if (mtd) {
                if (mtd->size > map->size) {
                        printk(KERN_WARNING "Reducing visibility of %ldKiB chip to %ldKiB\n",
                               (unsigned long)mtd->size >> 10,
                               (unsigned long)map->size >> 10);
                        mtd->size = map->size;
                }
                return mtd;
        }

        printk(KERN_WARNING"gen_probe: No supported Vendor Command Set found\n");

        kfree(cfi->cfiq);
        kfree(cfi);
        map->fldrv_priv = NULL;
        return NULL;
}
EXPORT_SYMBOL(mtd_do_chip_probe);


static struct cfi_private *genprobe_ident_chips(struct map_info *map, struct chip_probe *cp)
{
        struct cfi_private cfi;
        struct cfi_private *retcfi;
        unsigned long *chip_map;
        int max_chips;
        int i, j;

        memset(&cfi, 0, sizeof(cfi));

        /* Call the probetype-specific code with all permutations of
           interleave and device type, etc. */
        if (!genprobe_new_chip(map, cp, &cfi)) {
                /* The probe didn't like it */
                pr_debug("%s: Found no %s device at location zero\n",
                         cp->name, map->name);
                return NULL;
        }

#if 0 /* Let the CFI probe routine do this sanity check. The Intel and AMD
         probe routines won't ever return a broken CFI structure anyway,
         because they make them up themselves.
      */
        if (cfi.cfiq->NumEraseRegions == 0) {
                printk(KERN_WARNING "Number of erase regions is zero\n");
                kfree(cfi.cfiq);
                return NULL;
        }
#endif
        cfi.chipshift = cfi.cfiq->DevSize;

        if (cfi_interleave_is_1(&cfi)) {
                ;
        } else if (cfi_interleave_is_2(&cfi)) {
                cfi.chipshift++;
        } else if (cfi_interleave_is_4((&cfi))) {
                cfi.chipshift += 2;
        } else if (cfi_interleave_is_8(&cfi)) {
                cfi.chipshift += 3;
        } else {
                BUG();
        }

        cfi.numchips = 1;

        /*
         * Allocate memory for bitmap of valid chips.
         * Align bitmap storage size to full byte.
         */
        max_chips = map->size >> cfi.chipshift;
        if (!max_chips) {
                printk(KERN_WARNING "NOR chip too large to fit in mapping. Attempting to cope...\n");
                max_chips = 1;
        }

        chip_map = bitmap_zalloc(max_chips, GFP_KERNEL);
        if (!chip_map) {
                kfree(cfi.cfiq);
                return NULL;
        }

        set_bit(0, chip_map); /* Mark first chip valid */

        /*
         * Now probe for other chips, checking sensibly for aliases while
         * we're at it. The new_chip probe above should have let the first
         * chip in read mode.
         */

        for (i = 1; i < max_chips; i++) {
                cp->probe_chip(map, i << cfi.chipshift, chip_map, &cfi);
        }

        /*
         * Now allocate the space for the structures we need to return to
         * our caller, and copy the appropriate data into them.
         */

        retcfi = kmalloc_flex(*retcfi, chips, cfi.numchips);

        if (!retcfi) {
                kfree(cfi.cfiq);
                bitmap_free(chip_map);
                return NULL;
        }

        memcpy(retcfi, &cfi, sizeof(cfi));
        memset(&retcfi->chips[0], 0, sizeof(struct flchip) * cfi.numchips);

        for (i = 0, j = 0; (j < cfi.numchips) && (i < max_chips); i++) {
                if(test_bit(i, chip_map)) {
                        struct flchip *pchip = &retcfi->chips[j++];

                        pchip->start = (i << cfi.chipshift);
                        pchip->state = FL_READY;
                        init_waitqueue_head(&pchip->wq);
                        mutex_init(&pchip->mutex);
                }
        }

        bitmap_free(chip_map);
        return retcfi;
}


static int genprobe_new_chip(struct map_info *map, struct chip_probe *cp,
                             struct cfi_private *cfi)
{
        int min_chips = (map_bankwidth(map)/4?:1); /* At most 4-bytes wide. */
        int max_chips = map_bankwidth(map); /* And minimum 1 */
        int nr_chips, type;

        for (nr_chips = max_chips; nr_chips >= min_chips; nr_chips >>= 1) {

                if (!cfi_interleave_supported(nr_chips))
                    continue;

                cfi->interleave = nr_chips;

                /* Minimum device size. Don't look for one 8-bit device
                   in a 16-bit bus, etc. */
                type = map_bankwidth(map) / nr_chips;

                for (; type <= CFI_DEVICETYPE_X32; type<<=1) {
                        cfi->device_type = type;

                        if (cp->probe_chip(map, 0, NULL, cfi))
                                return 1;
                }
        }
        return 0;
}

typedef struct mtd_info *cfi_cmdset_fn_t(struct map_info *, int);

extern cfi_cmdset_fn_t cfi_cmdset_0001;
extern cfi_cmdset_fn_t cfi_cmdset_0002;
extern cfi_cmdset_fn_t cfi_cmdset_0020;

static inline struct mtd_info *cfi_cmdset_unknown(struct map_info *map,
                                                  int primary)
{
        struct cfi_private *cfi = map->fldrv_priv;
        __u16 type = primary?cfi->cfiq->P_ID:cfi->cfiq->A_ID;
#ifdef CONFIG_MODULES
        cfi_cmdset_fn_t *probe_function;
        char *probename;

        probename = kasprintf(GFP_KERNEL, "cfi_cmdset_%4.4X", type);
        if (!probename)
                return NULL;

        probe_function = __symbol_get(probename);
        if (!probe_function) {
                request_module("cfi_cmdset_%4.4X", type);
                probe_function = __symbol_get(probename);
        }
        kfree(probename);

        if (probe_function) {
                struct mtd_info *mtd;

                mtd = (*probe_function)(map, primary);
                /* If it was happy, it'll have increased its own use count */
                symbol_put_addr(probe_function);
                return mtd;
        }
#endif
        printk(KERN_NOTICE "Support for command set %04X not present\n", type);

        return NULL;
}

static struct mtd_info *check_cmd_set(struct map_info *map, int primary)
{
        struct cfi_private *cfi = map->fldrv_priv;
        __u16 type = primary?cfi->cfiq->P_ID:cfi->cfiq->A_ID;

        if (type == P_ID_NONE || type == P_ID_RESERVED)
                return NULL;

        switch(type){
                /* We need these for the !CONFIG_MODULES case,
                   because symbol_get() doesn't work there */
#ifdef CONFIG_MTD_CFI_INTELEXT
        case P_ID_INTEL_EXT:
        case P_ID_INTEL_STD:
        case P_ID_INTEL_PERFORMANCE:
                return cfi_cmdset_0001(map, primary);
#endif
#ifdef CONFIG_MTD_CFI_AMDSTD
        case P_ID_AMD_STD:
        case P_ID_SST_OLD:
        case P_ID_WINBOND:
                return cfi_cmdset_0002(map, primary);
#endif
#ifdef CONFIG_MTD_CFI_STAA
        case P_ID_ST_ADV:
                return cfi_cmdset_0020(map, primary);
#endif
        default:
                return cfi_cmdset_unknown(map, primary);
        }
}

MODULE_LICENSE("GPL");
MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
MODULE_DESCRIPTION("Helper routines for flash chip probe code");