// SPDX-License-Identifier: GPL-2.0
/*
   Common Flash Interface probe code.
   (C) 2000 Red Hat.
*/

#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <asm/io.h>
#include <asm/byteorder.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/interrupt.h>

#include <linux/mtd/xip.h>
#include <linux/mtd/map.h>
#include <linux/mtd/cfi.h>
#include <linux/mtd/gen_probe.h>

//#define DEBUG_CFI

#ifdef DEBUG_CFI
static void print_cfi_ident(struct cfi_ident *);
#endif

static int cfi_probe_chip(struct map_info *map, __u32 base,
                          unsigned long *chip_map, struct cfi_private *cfi);
static int cfi_chip_setup(struct map_info *map, struct cfi_private *cfi);

struct mtd_info *cfi_probe(struct map_info *map);

#ifdef CONFIG_MTD_XIP

/* only needed for short periods, so this is rather simple */
#define xip_disable()   local_irq_disable()

#define xip_allowed(base, map) \
do { \
        (void) map_read(map, base); \
        xip_iprefetch(); \
        local_irq_enable(); \
} while (0)

#define xip_enable(base, map, cfi) \
do { \
        cfi_qry_mode_off(base, map, cfi);               \
        xip_allowed(base, map); \
} while (0)

#define xip_disable_qry(base, map, cfi) \
do { \
        xip_disable(); \
        cfi_qry_mode_on(base, map, cfi); \
} while (0)

#else

#define xip_disable()                   do { } while (0)
#define xip_allowed(base, map)          do { } while (0)
#define xip_enable(base, map, cfi)      do { } while (0)
#define xip_disable_qry(base, map, cfi) do { } while (0)

#endif

/*
 * This fixup occurs immediately after reading the CFI structure and can affect
 * the number of chips detected, unlike cfi_fixup, which occurs after an
 * mtd_info structure has been created for the chip.
 */
struct cfi_early_fixup {
        uint16_t mfr;
        uint16_t id;
        void (*fixup)(struct cfi_private *cfi);
};

static void cfi_early_fixup(struct cfi_private *cfi,
                            const struct cfi_early_fixup *fixups)
{
        const struct cfi_early_fixup *f;

        for (f = fixups; f->fixup; f++) {
                if (((f->mfr == CFI_MFR_ANY) || (f->mfr == cfi->mfr)) &&
                    ((f->id == CFI_ID_ANY) || (f->id == cfi->id))) {
                        f->fixup(cfi);
                }
        }
}

/* check for QRY.
   in: interleave,type,mode
   ret: table index, <0 for error
 */

static int __xipram cfi_probe_chip(struct map_info *map, __u32 base,
                                   unsigned long *chip_map, struct cfi_private *cfi)
{
        int i;

        if ((base + 0) >= map->size) {
                printk(KERN_NOTICE
                        "Probe at base[0x00](0x%08lx) past the end of the map(0x%08lx)\n",
                        (unsigned long)base, map->size -1);
                return 0;
        }
        if ((base + 0xff) >= map->size) {
                printk(KERN_NOTICE
                        "Probe at base[0x55](0x%08lx) past the end of the map(0x%08lx)\n",
                        (unsigned long)base + 0x55, map->size -1);
                return 0;
        }

        xip_disable();
        if (!cfi_qry_mode_on(base, map, cfi)) {
                xip_enable(base, map, cfi);
                return 0;
        }

        if (!cfi->numchips) {
                /* This is the first time we're called. Set up the CFI
                   stuff accordingly and return */
                return cfi_chip_setup(map, cfi);
        }

        /* Check each previous chip to see if it's an alias */
        for (i=0; i < (base >> cfi->chipshift); i++) {
                unsigned long start;
                if(!test_bit(i, chip_map)) {
                        /* Skip location; no valid chip at this address */
                        continue;
                }
                start = i << cfi->chipshift;
                /* This chip should be in read mode if it's one
                   we've already touched. */
                if (cfi_qry_present(map, start, cfi)) {
                        /* Eep. This chip also had the QRY marker.
                         * Is it an alias for the new one? */
                        cfi_qry_mode_off(start, map, cfi);

                        /* If the QRY marker goes away, it's an alias */
                        if (!cfi_qry_present(map, start, cfi)) {
                                xip_allowed(base, map);
                                printk(KERN_DEBUG "%s: Found an alias at 0x%x for the chip at 0x%lx\n",
                                       map->name, base, start);
                                return 0;
                        }
                        /* Yes, it's actually got QRY for data. Most
                         * unfortunate. Stick the new chip in read mode
                         * too and if it's the same, assume it's an alias. */
                        /* FIXME: Use other modes to do a proper check */
                        cfi_qry_mode_off(base, map, cfi);

                        if (cfi_qry_present(map, base, cfi)) {
                                xip_allowed(base, map);
                                printk(KERN_DEBUG "%s: Found an alias at 0x%x for the chip at 0x%lx\n",
                                       map->name, base, start);
                                return 0;
                        }
                }
        }

        /* OK, if we got to here, then none of the previous chips appear to
           be aliases for the current one. */
        set_bit((base >> cfi->chipshift), chip_map); /* Update chip map */
        cfi->numchips++;

        /* Put it back into Read Mode */
        cfi_qry_mode_off(base, map, cfi);
        xip_allowed(base, map);

        printk(KERN_INFO "%s: Found %d x%d devices at 0x%x in %d-bit bank\n",
               map->name, cfi->interleave, cfi->device_type*8, base,
               map->bankwidth*8);

        return 1;
}

static void fixup_s70gl02gs_chips(struct cfi_private *cfi)
{
        /*
         * S70GL02GS flash reports a single 256 MiB chip, but is really made up
         * of two 128 MiB chips with 1024 sectors each.
         */
        cfi->cfiq->DevSize = 27;
        cfi->cfiq->EraseRegionInfo[0] = 0x20003ff;
        pr_warn("Bad S70GL02GS CFI data; adjust to detect 2 chips\n");
}

static const struct cfi_early_fixup cfi_early_fixup_table[] = {
        { CFI_MFR_AMD, 0x4801, fixup_s70gl02gs_chips },
        { },
};

static int __xipram cfi_chip_setup(struct map_info *map,
                                   struct cfi_private *cfi)
{
        int ofs_factor = cfi->interleave*cfi->device_type;
        __u32 base = 0;
        int num_erase_regions = cfi_read_query(map, base + (0x10 + 28)*ofs_factor);
        int i;
        int addr_unlock1 = 0x555, addr_unlock2 = 0x2AA;

        xip_enable(base, map, cfi);
#ifdef DEBUG_CFI
        printk("Number of erase regions: %d\n", num_erase_regions);
#endif
        if (!num_erase_regions)
                return 0;

        cfi->cfiq = kmalloc_flex(*cfi->cfiq, EraseRegionInfo, num_erase_regions);
        if (!cfi->cfiq)
                return 0;

        memset(cfi->cfiq,0,sizeof(struct cfi_ident));

        cfi->cfi_mode = CFI_MODE_CFI;

        cfi->sector_erase_cmd = CMD(0x30);

        /* Read the CFI info structure */
        xip_disable_qry(base, map, cfi);
        for (i=0; i<(sizeof(struct cfi_ident) + num_erase_regions * 4); i++)
                ((unsigned char *)cfi->cfiq)[i] = cfi_read_query(map,base + (0x10 + i)*ofs_factor);

        /* Do any necessary byteswapping */
        cfi->cfiq->P_ID = le16_to_cpu(cfi->cfiq->P_ID);

        cfi->cfiq->P_ADR = le16_to_cpu(cfi->cfiq->P_ADR);
        cfi->cfiq->A_ID = le16_to_cpu(cfi->cfiq->A_ID);
        cfi->cfiq->A_ADR = le16_to_cpu(cfi->cfiq->A_ADR);
        cfi->cfiq->InterfaceDesc = le16_to_cpu(cfi->cfiq->InterfaceDesc);
        cfi->cfiq->MaxBufWriteSize = le16_to_cpu(cfi->cfiq->MaxBufWriteSize);

#ifdef DEBUG_CFI
        /* Dump the information therein */
        print_cfi_ident(cfi->cfiq);
#endif

        for (i=0; i<cfi->cfiq->NumEraseRegions; i++) {
                cfi->cfiq->EraseRegionInfo[i] = le32_to_cpu(cfi->cfiq->EraseRegionInfo[i]);

#ifdef DEBUG_CFI
                printk("  Erase Region #%d: BlockSize 0x%4.4X bytes, %d blocks\n",
                       i, (cfi->cfiq->EraseRegionInfo[i] >> 8) & ~0xff,
                       (cfi->cfiq->EraseRegionInfo[i] & 0xffff) + 1);
#endif
        }

        if (cfi->cfiq->P_ID == P_ID_SST_OLD) {
                addr_unlock1 = 0x5555;
                addr_unlock2 = 0x2AAA;
        }

        /*
         * Note we put the device back into Read Mode BEFORE going into Auto
         * Select Mode, as some devices support nesting of modes, others
         * don't. This way should always work.
         * On cmdset 0001 the writes of 0xaa and 0x55 are not needed, and
         * so should be treated as nops or illegal (and so put the device
         * back into Read Mode, which is a nop in this case).
         */
        cfi_send_gen_cmd(0xf0,     0, base, map, cfi, cfi->device_type, NULL);
        cfi_send_gen_cmd(0xaa, addr_unlock1, base, map, cfi, cfi->device_type, NULL);
        cfi_send_gen_cmd(0x55, addr_unlock2, base, map, cfi, cfi->device_type, NULL);
        cfi_send_gen_cmd(0x90, addr_unlock1, base, map, cfi, cfi->device_type, NULL);
        cfi->mfr = cfi_read_query16(map, base);
        cfi->id = cfi_read_query16(map, base + ofs_factor);

        /* Get AMD/Spansion extended JEDEC ID */
        if (cfi->mfr == CFI_MFR_AMD && (cfi->id & 0xff) == 0x7e)
                cfi->id = cfi_read_query(map, base + 0xe * ofs_factor) << 8 |
                          cfi_read_query(map, base + 0xf * ofs_factor);

        /* Put it back into Read Mode */
        cfi_qry_mode_off(base, map, cfi);
        xip_allowed(base, map);

        cfi_early_fixup(cfi, cfi_early_fixup_table);

        printk(KERN_INFO "%s: Found %d x%d devices at 0x%x in %d-bit bank. Manufacturer ID %#08x Chip ID %#08x\n",
               map->name, cfi->interleave, cfi->device_type*8, base,
               map->bankwidth*8, cfi->mfr, cfi->id);

        return 1;
}

#ifdef DEBUG_CFI
static char *vendorname(__u16 vendor)
{
        switch (vendor) {
        case P_ID_NONE:
                return "None";

        case P_ID_INTEL_EXT:
                return "Intel/Sharp Extended";

        case P_ID_AMD_STD:
                return "AMD/Fujitsu Standard";

        case P_ID_INTEL_STD:
                return "Intel/Sharp Standard";

        case P_ID_AMD_EXT:
                return "AMD/Fujitsu Extended";

        case P_ID_WINBOND:
                return "Winbond Standard";

        case P_ID_ST_ADV:
                return "ST Advanced";

        case P_ID_MITSUBISHI_STD:
                return "Mitsubishi Standard";

        case P_ID_MITSUBISHI_EXT:
                return "Mitsubishi Extended";

        case P_ID_SST_PAGE:
                return "SST Page Write";

        case P_ID_SST_OLD:
                return "SST 39VF160x/39VF320x";

        case P_ID_INTEL_PERFORMANCE:
                return "Intel Performance Code";

        case P_ID_INTEL_DATA:
                return "Intel Data";

        case P_ID_RESERVED:
                return "Not Allowed / Reserved for Future Use";

        default:
                return "Unknown";
        }
}


static void print_cfi_ident(struct cfi_ident *cfip)
{
#if 0
        if (cfip->qry[0] != 'Q' || cfip->qry[1] != 'R' || cfip->qry[2] != 'Y') {
                printk("Invalid CFI ident structure.\n");
                return;
        }
#endif
        printk("Primary Vendor Command Set: %4.4X (%s)\n", cfip->P_ID, vendorname(cfip->P_ID));
        if (cfip->P_ADR)
                printk("Primary Algorithm Table at %4.4X\n", cfip->P_ADR);
        else
                printk("No Primary Algorithm Table\n");

        printk("Alternative Vendor Command Set: %4.4X (%s)\n", cfip->A_ID, vendorname(cfip->A_ID));
        if (cfip->A_ADR)
                printk("Alternate Algorithm Table at %4.4X\n", cfip->A_ADR);
        else
                printk("No Alternate Algorithm Table\n");


        printk("Vcc Minimum: %2d.%d V\n", cfip->VccMin >> 4, cfip->VccMin & 0xf);
        printk("Vcc Maximum: %2d.%d V\n", cfip->VccMax >> 4, cfip->VccMax & 0xf);
        if (cfip->VppMin) {
                printk("Vpp Minimum: %2d.%d V\n", cfip->VppMin >> 4, cfip->VppMin & 0xf);
                printk("Vpp Maximum: %2d.%d V\n", cfip->VppMax >> 4, cfip->VppMax & 0xf);
        }
        else
                printk("No Vpp line\n");

        printk("Typical byte/word write timeout: %d µs\n", 1<<cfip->WordWriteTimeoutTyp);
        printk("Maximum byte/word write timeout: %d µs\n", (1<<cfip->WordWriteTimeoutMax) * (1<<cfip->WordWriteTimeoutTyp));

        if (cfip->BufWriteTimeoutTyp || cfip->BufWriteTimeoutMax) {
                printk("Typical full buffer write timeout: %d µs\n", 1<<cfip->BufWriteTimeoutTyp);
                printk("Maximum full buffer write timeout: %d µs\n", (1<<cfip->BufWriteTimeoutMax) * (1<<cfip->BufWriteTimeoutTyp));
        }
        else
                printk("Full buffer write not supported\n");

        printk("Typical block erase timeout: %d ms\n", 1<<cfip->BlockEraseTimeoutTyp);
        printk("Maximum block erase timeout: %d ms\n", (1<<cfip->BlockEraseTimeoutMax) * (1<<cfip->BlockEraseTimeoutTyp));
        if (cfip->ChipEraseTimeoutTyp || cfip->ChipEraseTimeoutMax) {
                printk("Typical chip erase timeout: %d ms\n", 1<<cfip->ChipEraseTimeoutTyp);
                printk("Maximum chip erase timeout: %d ms\n", (1<<cfip->ChipEraseTimeoutMax) * (1<<cfip->ChipEraseTimeoutTyp));
        }
        else
                printk("Chip erase not supported\n");

        printk("Device size: 0x%X bytes (%d MiB)\n", 1 << cfip->DevSize, 1<< (cfip->DevSize - 20));
        printk("Flash Device Interface description: 0x%4.4X\n", cfip->InterfaceDesc);
        switch(cfip->InterfaceDesc) {
        case CFI_INTERFACE_X8_ASYNC:
                printk("  - x8-only asynchronous interface\n");
                break;

        case CFI_INTERFACE_X16_ASYNC:
                printk("  - x16-only asynchronous interface\n");
                break;

        case CFI_INTERFACE_X8_BY_X16_ASYNC:
                printk("  - supports x8 and x16 via BYTE# with asynchronous interface\n");
                break;

        case CFI_INTERFACE_X32_ASYNC:
                printk("  - x32-only asynchronous interface\n");
                break;

        case CFI_INTERFACE_X16_BY_X32_ASYNC:
                printk("  - supports x16 and x32 via Word# with asynchronous interface\n");
                break;

        case CFI_INTERFACE_NOT_ALLOWED:
                printk("  - Not Allowed / Reserved\n");
                break;

        default:
                printk("  - Unknown\n");
                break;
        }

        printk("Max. bytes in buffer write: 0x%x\n", 1<< cfip->MaxBufWriteSize);
        printk("Number of Erase Block Regions: %d\n", cfip->NumEraseRegions);

}
#endif /* DEBUG_CFI */

static struct chip_probe cfi_chip_probe = {
        .name           = "CFI",
        .probe_chip     = cfi_probe_chip
};

struct mtd_info *cfi_probe(struct map_info *map)
{
        /*
         * Just use the generic probe stuff to call our CFI-specific
         * chip_probe routine in all the possible permutations, etc.
         */
        return mtd_do_chip_probe(map, &cfi_chip_probe);
}

static struct mtd_chip_driver cfi_chipdrv = {
        .probe          = cfi_probe,
        .name           = "cfi_probe",
        .module         = THIS_MODULE
};

static int __init cfi_probe_init(void)
{
        register_mtd_chip_driver(&cfi_chipdrv);
        return 0;
}

static void __exit cfi_probe_exit(void)
{
        unregister_mtd_chip_driver(&cfi_chipdrv);
}

module_init(cfi_probe_init);
module_exit(cfi_probe_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org> et al.");
MODULE_DESCRIPTION("Probe code for CFI-compliant flash chips");