This patch adds NAND flash controller driver for MediaTek MT7621 SoC.
The NAND flash controller of MT7621 supports only SLC NAND flashes.
It supports 4~12 bits correction with maximum 4KB page size.

Signed-off-by: Weijie Gao <weijie....@mediatek.com>
---
v2 changes: none
---
 drivers/mtd/nand/raw/Kconfig       |   11 +
 drivers/mtd/nand/raw/Makefile      |    1 +
 drivers/mtd/nand/raw/mt7621_nand.c | 1189 ++++++++++++++++++++++++++++
 3 files changed, 1201 insertions(+)
 create mode 100644 drivers/mtd/nand/raw/mt7621_nand.c

diff --git a/drivers/mtd/nand/raw/Kconfig b/drivers/mtd/nand/raw/Kconfig
index cb0c0a1581..fe87c521d7 100644
--- a/drivers/mtd/nand/raw/Kconfig
+++ b/drivers/mtd/nand/raw/Kconfig
@@ -475,6 +475,17 @@ config ROCKCHIP_NAND
            NFC v800: RK3308, RV1108
            NFC v900: PX30, RK3326
 
+config NAND_MT7621
+       bool "Support for MediaTek MT7621 NAND flash controller"
+       depends on SOC_MT7621
+       select SYS_NAND_SELF_INIT
+       imply CMD_NAND
+       help
+         This enables NAND driver for the NAND flash controller on MediaTek
+         MT7621 platform.
+         The controller supports 4~12 bits correction per 512 bytes with a
+         maximum 4KB page size.
+
 comment "Generic NAND options"
 
 config SYS_NAND_BLOCK_SIZE
diff --git a/drivers/mtd/nand/raw/Makefile b/drivers/mtd/nand/raw/Makefile
index 6ec3581d20..6d6721a3be 100644
--- a/drivers/mtd/nand/raw/Makefile
+++ b/drivers/mtd/nand/raw/Makefile
@@ -72,6 +72,7 @@ obj-$(CONFIG_NAND_ZYNQ) += zynq_nand.o
 obj-$(CONFIG_NAND_STM32_FMC2) += stm32_fmc2_nand.o
 obj-$(CONFIG_CORTINA_NAND) += cortina_nand.o
 obj-$(CONFIG_ROCKCHIP_NAND) += rockchip_nfc.o
+obj-$(CONFIG_NAND_MT7621) += mt7621_nand.o
 
 else  # minimal SPL drivers
 
diff --git a/drivers/mtd/nand/raw/mt7621_nand.c 
b/drivers/mtd/nand/raw/mt7621_nand.c
new file mode 100644
index 0000000000..e4fe5320f1
--- /dev/null
+++ b/drivers/mtd/nand/raw/mt7621_nand.c
@@ -0,0 +1,1189 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2021 MediaTek Incorporation. All Rights Reserved.
+ *
+ * Author: Weijie Gao <weijie....@mediatek.com>
+ */
+
+#include <log.h>
+#include <nand.h>
+#include <malloc.h>
+#include <asm/addrspace.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/sizes.h>
+#include <linux/bitops.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/rawnand.h>
+
+/* NFI core registers */
+#define NFI_CNFG                       0x000
+#define   CNFG_OP_MODE_S               12
+#define   CNFG_OP_MODE_M               GENMASK(14, 12)
+#define     CNFG_OP_CUSTOM             6
+#define   CNFG_AUTO_FMT_EN             BIT(9)
+#define   CNFG_HW_ECC_EN               BIT(8)
+#define   CNFG_BYTE_RW                 BIT(6)
+#define   CNFG_READ_MODE               BIT(1)
+
+#define NFI_PAGEFMT                    0x004
+#define   PAGEFMT_FDM_ECC_S            12
+#define   PAGEFMT_FDM_ECC_M            GENMASK(15, 12)
+#define   PAGEFMT_FDM_S                        8
+#define   PAGEFMT_FDM_M                        GENMASK(11, 8)
+#define   PAGEFMT_SPARE_S              4
+#define   PAGEFMT_SPARE_M              GENMASK(5, 4)
+#define   PAGEFMT_PAGE_S               0
+#define   PAGEFMT_PAGE_M               GENMASK(1, 0)
+
+#define NFI_CON                                0x008
+#define   CON_NFI_SEC_S                        12
+#define   CON_NFI_SEC_M                        GENMASK(15, 12)
+#define   CON_NFI_BWR                  BIT(9)
+#define   CON_NFI_BRD                  BIT(8)
+#define   CON_NFI_RST                  BIT(1)
+#define   CON_FIFO_FLUSH               BIT(0)
+
+#define NFI_ACCCON                     0x00c
+#define   ACCCON_POECS_S               28
+#define   ACCCON_POECS_MAX             0x0f
+#define   ACCCON_POECS_DEF             3
+#define   ACCCON_PRECS_S               22
+#define   ACCCON_PRECS_MAX             0x3f
+#define   ACCCON_PRECS_DEF             3
+#define   ACCCON_C2R_S                 16
+#define   ACCCON_C2R_MAX               0x3f
+#define   ACCCON_C2R_DEF               7
+#define   ACCCON_W2R_S                 12
+#define   ACCCON_W2R_MAX               0x0f
+#define   ACCCON_W2R_DEF               7
+#define   ACCCON_WH_S                  8
+#define   ACCCON_WH_MAX                        0x0f
+#define   ACCCON_WH_DEF                        15
+#define   ACCCON_WST_S                 4
+#define   ACCCON_WST_MAX               0x0f
+#define   ACCCON_WST_DEF               15
+#define   ACCCON_WST_MIN               3
+#define   ACCCON_RLT_S                 0
+#define   ACCCON_RLT_MAX               0x0f
+#define   ACCCON_RLT_DEF               15
+#define   ACCCON_RLT_MIN               3
+
+#define NFI_CMD                                0x020
+
+#define NFI_ADDRNOB                    0x030
+#define   ADDR_ROW_NOB_S               4
+#define   ADDR_ROW_NOB_M               GENMASK(6, 4)
+#define   ADDR_COL_NOB_S               0
+#define   ADDR_COL_NOB_M               GENMASK(2, 0)
+
+#define NFI_COLADDR                    0x034
+#define NFI_ROWADDR                    0x038
+
+#define NFI_STRDATA                    0x040
+#define   STR_DATA                     BIT(0)
+
+#define NFI_CNRNB                      0x044
+#define   CB2R_TIME_S                  4
+#define   CB2R_TIME_M                  GENMASK(7, 4)
+#define   STR_CNRNB                    BIT(0)
+
+#define NFI_DATAW                      0x050
+#define NFI_DATAR                      0x054
+
+#define NFI_PIO_DIRDY                  0x058
+#define   PIO_DIRDY                    BIT(0)
+
+#define NFI_STA                                0x060
+#define   STA_NFI_FSM_S                        16
+#define   STA_NFI_FSM_M                        GENMASK(19, 16)
+#define     STA_FSM_CUSTOM_DATA                14
+#define   STA_BUSY                     BIT(8)
+#define   STA_ADDR                     BIT(1)
+#define   STA_CMD                      BIT(0)
+
+#define NFI_ADDRCNTR                   0x070
+#define   SEC_CNTR_S                   12
+#define   SEC_CNTR_M                   GENMASK(15, 12)
+#define   SEC_ADDR_S                   0
+#define   SEC_ADDR_M                   GENMASK(9, 0)
+
+#define NFI_CSEL                       0x090
+#define   CSEL_S                       0
+#define   CSEL_M                       GENMASK(1, 0)
+
+#define NFI_FDM0L                      0x0a0
+#define NFI_FDML(n)                    (0x0a0 + ((n) << 3))
+
+#define NFI_FDM0M                      0x0a4
+#define NFI_FDMM(n)                    (0x0a4 + ((n) << 3))
+
+#define NFI_MASTER_STA                 0x210
+#define   MAS_ADDR                     GENMASK(11, 9)
+#define   MAS_RD                       GENMASK(8, 6)
+#define   MAS_WR                       GENMASK(5, 3)
+#define   MAS_RDDLY                    GENMASK(2, 0)
+
+/* ECC engine registers */
+#define ECC_ENCCON                     0x000
+#define   ENC_EN                       BIT(0)
+
+#define ECC_ENCCNFG                    0x004
+#define   ENC_CNFG_MSG_S               16
+#define   ENC_CNFG_MSG_M               GENMASK(28, 16)
+#define   ENC_MODE_S                   4
+#define   ENC_MODE_M                   GENMASK(5, 4)
+#define     ENC_MODE_NFI               1
+#define   ENC_TNUM_S                   0
+#define   ENC_TNUM_M                   GENMASK(2, 0)
+
+#define ECC_ENCIDLE                    0x00c
+#define   ENC_IDLE                     BIT(0)
+
+#define ECC_DECCON                     0x100
+#define   DEC_EN                       BIT(0)
+
+#define ECC_DECCNFG                    0x104
+#define   DEC_EMPTY_EN                 BIT(31)
+#define   DEC_CS_S                     16
+#define   DEC_CS_M                     GENMASK(28, 16)
+#define   DEC_CON_S                    12
+#define   DEC_CON_M                    GENMASK(13, 12)
+#define     DEC_CON_EL                 2
+#define   DEC_MODE_S                   4
+#define   DEC_MODE_M                   GENMASK(5, 4)
+#define     DEC_MODE_NFI               1
+#define   DEC_TNUM_S                   0
+#define   DEC_TNUM_M                   GENMASK(2, 0)
+
+#define ECC_DECIDLE                    0x10c
+#define   DEC_IDLE                     BIT(1)
+
+#define ECC_DECENUM                    0x114
+#define   ERRNUM_S                     2
+#define   ERRNUM_M                     GENMASK(3, 0)
+
+#define ECC_DECDONE                    0x118
+#define   DEC_DONE7                    BIT(7)
+#define   DEC_DONE6                    BIT(6)
+#define   DEC_DONE5                    BIT(5)
+#define   DEC_DONE4                    BIT(4)
+#define   DEC_DONE3                    BIT(3)
+#define   DEC_DONE2                    BIT(2)
+#define   DEC_DONE1                    BIT(1)
+#define   DEC_DONE0                    BIT(0)
+
+#define ECC_DECEL(n)                   (0x11c + (n) * 4)
+#define   DEC_EL_ODD_S                 16
+#define   DEC_EL_EVEN_S                        0
+#define   DEC_EL_M                     0x1fff
+#define   DEC_EL_BYTE_POS_S            3
+#define   DEC_EL_BIT_POS_M             GENMASK(3, 0)
+
+#define ECC_FDMADDR                    0x13c
+
+/* ENCIDLE and DECIDLE */
+#define   ECC_IDLE                     BIT(0)
+
+#define ACCTIMING(tpoecs, tprecs, tc2r, tw2r, twh, twst, trlt) \
+       ((tpoecs) << ACCCON_POECS_S | (tprecs) << ACCCON_PRECS_S | \
+       (tc2r) << ACCCON_C2R_S | (tw2r) << ACCCON_W2R_S | \
+       (twh) << ACCCON_WH_S | (twst) << ACCCON_WST_S | (trlt))
+
+#define MASTER_STA_MASK                        (MAS_ADDR | MAS_RD | MAS_WR | \
+                                        MAS_RDDLY)
+#define NFI_RESET_TIMEOUT              1000000
+#define NFI_CORE_TIMEOUT               500000
+#define ECC_ENGINE_TIMEOUT             500000
+
+#define ECC_SECTOR_SIZE                        512
+#define ECC_PARITY_BITS                        13
+
+#define NFI_FDM_SIZE                   8
+
+/* Register base */
+#define NFI_BASE                       0x1e003000
+#define NFI_ECC_BASE                   0x1e003800
+
+struct mt7621_nfc {
+       struct nand_chip nand;
+
+       void __iomem *nfi_regs;
+       void __iomem *ecc_regs;
+
+       u32 spare_per_sector;
+};
+
+static struct mt7621_nfc nfc_dev;
+
+static const u16 mt7621_nfi_page_size[] = { SZ_512, SZ_2K, SZ_4K };
+static const u8 mt7621_nfi_spare_size[] = { 16, 26, 27, 28 };
+static const u8 mt7621_ecc_strength[] = { 4, 6, 8, 10, 12 };
+
+static inline u32 nfi_read32(struct mt7621_nfc *nfc, u32 reg)
+{
+       return readl(nfc->nfi_regs + reg);
+}
+
+static inline void nfi_write32(struct mt7621_nfc *nfc, u32 reg, u32 val)
+{
+       writel(val, nfc->nfi_regs + reg);
+}
+
+static inline u16 nfi_read16(struct mt7621_nfc *nfc, u32 reg)
+{
+       return readw(nfc->nfi_regs + reg);
+}
+
+static inline void nfi_write16(struct mt7621_nfc *nfc, u32 reg, u16 val)
+{
+       writew(val, nfc->nfi_regs + reg);
+}
+
+static inline void ecc_write16(struct mt7621_nfc *nfc, u32 reg, u16 val)
+{
+       writew(val, nfc->ecc_regs + reg);
+}
+
+static inline u32 ecc_read32(struct mt7621_nfc *nfc, u32 reg)
+{
+       return readl(nfc->ecc_regs + reg);
+}
+
+static inline void ecc_write32(struct mt7621_nfc *nfc, u32 reg, u32 val)
+{
+       return writel(val, nfc->ecc_regs + reg);
+}
+
+static inline u8 *oob_fdm_ptr(struct nand_chip *nand, int sect)
+{
+       return nand->oob_poi + sect * NFI_FDM_SIZE;
+}
+
+static inline u8 *oob_ecc_ptr(struct mt7621_nfc *nfc, int sect)
+{
+       struct nand_chip *nand = &nfc->nand;
+
+       return nand->oob_poi + nand->ecc.steps * NFI_FDM_SIZE +
+               sect * (nfc->spare_per_sector - NFI_FDM_SIZE);
+}
+
+static inline u8 *page_data_ptr(struct nand_chip *nand, const u8 *buf,
+                               int sect)
+{
+       return (u8 *)buf + sect * nand->ecc.size;
+}
+
+static int mt7621_ecc_wait_idle(struct mt7621_nfc *nfc, u32 reg)
+{
+       u32 val;
+       int ret;
+
+       ret = readw_poll_timeout(nfc->ecc_regs + reg, val, val & ECC_IDLE,
+                                ECC_ENGINE_TIMEOUT);
+       if (ret) {
+               pr_warn("ECC engine timed out entering idle mode\n");
+               return -EIO;
+       }
+
+       return 0;
+}
+
+static int mt7621_ecc_decoder_wait_done(struct mt7621_nfc *nfc, u32 sect)
+{
+       u32 val;
+       int ret;
+
+       ret = readw_poll_timeout(nfc->ecc_regs + ECC_DECDONE, val,
+                                val & (1 << sect), ECC_ENGINE_TIMEOUT);
+       if (ret) {
+               pr_warn("ECC decoder for sector %d timed out\n", sect);
+               return -ETIMEDOUT;
+       }
+
+       return 0;
+}
+
+static void mt7621_ecc_encoder_op(struct mt7621_nfc *nfc, bool enable)
+{
+       mt7621_ecc_wait_idle(nfc, ECC_ENCIDLE);
+       ecc_write16(nfc, ECC_ENCCON, enable ? ENC_EN : 0);
+}
+
+static void mt7621_ecc_decoder_op(struct mt7621_nfc *nfc, bool enable)
+{
+       mt7621_ecc_wait_idle(nfc, ECC_DECIDLE);
+       ecc_write16(nfc, ECC_DECCON, enable ? DEC_EN : 0);
+}
+
+static int mt7621_ecc_correct_check(struct mt7621_nfc *nfc, u8 *sector_buf,
+                                   u8 *fdm_buf, u32 sect)
+{
+       struct nand_chip *nand = &nfc->nand;
+       u32 decnum, num_error_bits, fdm_end_bits;
+       u32 error_locations, error_bit_loc;
+       u32 error_byte_pos, error_bit_pos;
+       int bitflips = 0;
+       u32 i;
+
+       decnum = ecc_read32(nfc, ECC_DECENUM);
+       num_error_bits = (decnum >> (sect << ERRNUM_S)) & ERRNUM_M;
+       fdm_end_bits = (nand->ecc.size + NFI_FDM_SIZE) << 3;
+
+       if (!num_error_bits)
+               return 0;
+
+       if (num_error_bits == ERRNUM_M)
+               return -1;
+
+       for (i = 0; i < num_error_bits; i++) {
+               error_locations = ecc_read32(nfc, ECC_DECEL(i / 2));
+               error_bit_loc = (error_locations >> ((i % 2) * DEC_EL_ODD_S)) &
+                               DEC_EL_M;
+               error_byte_pos = error_bit_loc >> DEC_EL_BYTE_POS_S;
+               error_bit_pos = error_bit_loc & DEC_EL_BIT_POS_M;
+
+               if (error_bit_loc < (nand->ecc.size << 3)) {
+                       if (sector_buf) {
+                               sector_buf[error_byte_pos] ^=
+                                       (1 << error_bit_pos);
+                       }
+               } else if (error_bit_loc < fdm_end_bits) {
+                       if (fdm_buf) {
+                               fdm_buf[error_byte_pos - nand->ecc.size] ^=
+                                       (1 << error_bit_pos);
+                       }
+               }
+
+               bitflips++;
+       }
+
+       return bitflips;
+}
+
+static int mt7621_nfc_wait_write_completion(struct mt7621_nfc *nfc,
+                                           struct nand_chip *nand)
+{
+       u16 val;
+       int ret;
+
+       ret = readw_poll_timeout(nfc->nfi_regs + NFI_ADDRCNTR, val,
+               ((val & SEC_CNTR_M) >> SEC_CNTR_S) >= nand->ecc.steps,
+               NFI_CORE_TIMEOUT);
+
+       if (ret) {
+               pr_warn("NFI core write operation timed out\n");
+               return -ETIMEDOUT;
+       }
+
+       return ret;
+}
+
+static void mt7621_nfc_hw_reset(struct mt7621_nfc *nfc)
+{
+       u32 val;
+       int ret;
+
+       /* reset all registers and force the NFI master to terminate */
+       nfi_write16(nfc, NFI_CON, CON_FIFO_FLUSH | CON_NFI_RST);
+
+       /* wait for the master to finish the last transaction */
+       ret = readw_poll_timeout(nfc->nfi_regs + NFI_MASTER_STA, val,
+                                !(val & MASTER_STA_MASK), NFI_RESET_TIMEOUT);
+       if (ret) {
+               pr_warn("Failed to reset NFI master in %dms\n",
+                       NFI_RESET_TIMEOUT);
+       }
+
+       /* ensure any status register affected by the NFI master is reset */
+       nfi_write16(nfc, NFI_CON, CON_FIFO_FLUSH | CON_NFI_RST);
+       nfi_write16(nfc, NFI_STRDATA, 0);
+}
+
+static inline void mt7621_nfc_hw_init(struct mt7621_nfc *nfc)
+{
+       u32 acccon;
+
+       /*
+        * CNRNB: nand ready/busy register
+        * -------------------------------
+        * 7:4: timeout register for polling the NAND busy/ready signal
+        * 0  : poll the status of the busy/ready signal after [7:4]*16 cycles.
+        */
+       nfi_write16(nfc, NFI_CNRNB, CB2R_TIME_M | STR_CNRNB);
+
+       mt7621_nfc_hw_reset(nfc);
+
+       /* Apply default access timing */
+       acccon = ACCTIMING(ACCCON_POECS_DEF, ACCCON_PRECS_DEF, ACCCON_C2R_DEF,
+                          ACCCON_W2R_DEF, ACCCON_WH_DEF, ACCCON_WST_DEF,
+                          ACCCON_RLT_DEF);
+
+       nfi_write32(nfc, NFI_ACCCON, acccon);
+}
+
+static int mt7621_nfc_send_command(struct mt7621_nfc *nfc, u8 command)
+{
+       u32 val;
+       int ret;
+
+       nfi_write32(nfc, NFI_CMD, command);
+
+       ret = readl_poll_timeout(nfc->nfi_regs + NFI_STA, val, !(val & STA_CMD),
+                                NFI_CORE_TIMEOUT);
+       if (ret) {
+               pr_warn("NFI core timed out entering command mode\n");
+               return -EIO;
+       }
+
+       return 0;
+}
+
+static int mt7621_nfc_send_address_byte(struct mt7621_nfc *nfc, int addr)
+{
+       u32 val;
+       int ret;
+
+       nfi_write32(nfc, NFI_COLADDR, addr);
+       nfi_write32(nfc, NFI_ROWADDR, 0);
+       nfi_write16(nfc, NFI_ADDRNOB, 1);
+
+       ret = readl_poll_timeout(nfc->nfi_regs + NFI_STA, val,
+                                !(val & STA_ADDR), NFI_CORE_TIMEOUT);
+       if (ret) {
+               pr_warn("NFI core timed out entering address mode\n");
+               return -EIO;
+       }
+
+       return 0;
+}
+
+static void mt7621_nfc_cmd_ctrl(struct mtd_info *mtd, int dat,
+                               unsigned int ctrl)
+{
+       struct mt7621_nfc *nfc = nand_get_controller_data(mtd_to_nand(mtd));
+
+       if (ctrl & NAND_ALE) {
+               mt7621_nfc_send_address_byte(nfc, dat & 0xff);
+       } else if (ctrl & NAND_CLE) {
+               mt7621_nfc_hw_reset(nfc);
+               nfi_write16(nfc, NFI_CNFG, CNFG_OP_CUSTOM << CNFG_OP_MODE_S);
+               mt7621_nfc_send_command(nfc, dat);
+       }
+}
+
+static int mt7621_nfc_dev_ready(struct mtd_info *mtd)
+{
+       struct mt7621_nfc *nfc = nand_get_controller_data(mtd_to_nand(mtd));
+
+       if (nfi_read32(nfc, NFI_STA) & STA_BUSY)
+               return 0;
+
+       return 1;
+}
+
+static void mt7621_nfc_select_chip(struct mtd_info *mtd, int chipnr)
+{
+       struct mt7621_nfc *nfc = nand_get_controller_data(mtd_to_nand(mtd));
+
+       nfi_write16(nfc, NFI_CSEL, 0);
+}
+
+static void mt7621_nfc_wait_pio_ready(struct mt7621_nfc *nfc)
+{
+       int ret;
+       u16 val;
+
+       ret = readw_poll_timeout(nfc->nfi_regs + NFI_PIO_DIRDY, val,
+                                val & PIO_DIRDY, NFI_CORE_TIMEOUT);
+       if (ret < 0)
+               pr_err("NFI core PIO mode not ready\n");
+}
+
+static u32 mt7621_nfc_pio_read(struct mt7621_nfc *nfc, bool br)
+{
+       u32 reg;
+
+       /* after each byte read, the NFI_STA reg is reset by the hardware */
+       reg = (nfi_read32(nfc, NFI_STA) & STA_NFI_FSM_M) >> STA_NFI_FSM_S;
+       if (reg != STA_FSM_CUSTOM_DATA) {
+               reg = nfi_read16(nfc, NFI_CNFG);
+               reg |= CNFG_READ_MODE | CNFG_BYTE_RW;
+               if (!br)
+                       reg &= ~CNFG_BYTE_RW;
+               nfi_write16(nfc, NFI_CNFG, reg);
+
+               /*
+                * set to max sector to allow the HW to continue reading over
+                * unaligned accesses
+                */
+               nfi_write16(nfc, NFI_CON, CON_NFI_SEC_M | CON_NFI_BRD);
+
+               /* trigger to fetch data */
+               nfi_write16(nfc, NFI_STRDATA, STR_DATA);
+       }
+
+       mt7621_nfc_wait_pio_ready(nfc);
+
+       return nfi_read32(nfc, NFI_DATAR);
+}
+
+static void mt7621_nfc_read_data(struct mt7621_nfc *nfc, u8 *buf, u32 len)
+{
+       while (((uintptr_t)buf & 3) && len) {
+               *buf = mt7621_nfc_pio_read(nfc, true);
+               buf++;
+               len--;
+       }
+
+       while (len >= 4) {
+               *(u32 *)buf = mt7621_nfc_pio_read(nfc, false);
+               buf += 4;
+               len -= 4;
+       }
+
+       while (len) {
+               *buf = mt7621_nfc_pio_read(nfc, true);
+               buf++;
+               len--;
+       }
+}
+
+static void mt7621_nfc_read_data_discard(struct mt7621_nfc *nfc, u32 len)
+{
+       while (len >= 4) {
+               mt7621_nfc_pio_read(nfc, false);
+               len -= 4;
+       }
+
+       while (len) {
+               mt7621_nfc_pio_read(nfc, true);
+               len--;
+       }
+}
+
+static void mt7621_nfc_pio_write(struct mt7621_nfc *nfc, u32 val, bool bw)
+{
+       u32 reg;
+
+       reg = (nfi_read32(nfc, NFI_STA) & STA_NFI_FSM_M) >> STA_NFI_FSM_S;
+       if (reg != STA_FSM_CUSTOM_DATA) {
+               reg = nfi_read16(nfc, NFI_CNFG);
+               reg &= ~(CNFG_READ_MODE | CNFG_BYTE_RW);
+               if (bw)
+                       reg |= CNFG_BYTE_RW;
+               nfi_write16(nfc, NFI_CNFG, reg);
+
+               nfi_write16(nfc, NFI_CON, CON_NFI_SEC_M | CON_NFI_BWR);
+               nfi_write16(nfc, NFI_STRDATA, STR_DATA);
+       }
+
+       mt7621_nfc_wait_pio_ready(nfc);
+       nfi_write32(nfc, NFI_DATAW, val);
+}
+
+static void mt7621_nfc_write_data(struct mt7621_nfc *nfc, const u8 *buf,
+                                 u32 len)
+{
+       while (((uintptr_t)buf & 3) && len) {
+               mt7621_nfc_pio_write(nfc, *buf, true);
+               buf++;
+               len--;
+       }
+
+       while (len >= 4) {
+               mt7621_nfc_pio_write(nfc, *(const u32 *)buf, false);
+               buf += 4;
+               len -= 4;
+       }
+
+       while (len) {
+               mt7621_nfc_pio_write(nfc, *buf, true);
+               buf++;
+               len--;
+       }
+}
+
+static void mt7621_nfc_write_data_empty(struct mt7621_nfc *nfc, u32 len)
+{
+       while (len >= 4) {
+               mt7621_nfc_pio_write(nfc, 0xffffffff, false);
+               len -= 4;
+       }
+
+       while (len) {
+               mt7621_nfc_pio_write(nfc, 0xff, true);
+               len--;
+       }
+}
+
+static void mt7621_nfc_write_byte(struct mtd_info *mtd, u8 byte)
+{
+       struct mt7621_nfc *nfc = nand_get_controller_data(mtd_to_nand(mtd));
+
+       mt7621_nfc_pio_write(nfc, byte, true);
+}
+
+static void mt7621_nfc_write_buf(struct mtd_info *mtd, const u8 *buf, int len)
+{
+       struct mt7621_nfc *nfc = nand_get_controller_data(mtd_to_nand(mtd));
+
+       return mt7621_nfc_write_data(nfc, buf, len);
+}
+
+static u8 mt7621_nfc_read_byte(struct mtd_info *mtd)
+{
+       struct mt7621_nfc *nfc = nand_get_controller_data(mtd_to_nand(mtd));
+
+       return mt7621_nfc_pio_read(nfc, true);
+}
+
+static void mt7621_nfc_read_buf(struct mtd_info *mtd, u8 *buf, int len)
+{
+       struct mt7621_nfc *nfc = nand_get_controller_data(mtd_to_nand(mtd));
+
+       mt7621_nfc_read_data(nfc, buf, len);
+}
+
+static int mt7621_nfc_calc_ecc_strength(struct mt7621_nfc *nfc,
+                                       u32 avail_ecc_bytes)
+{
+       struct nand_chip *nand = &nfc->nand;
+       struct mtd_info *mtd = nand_to_mtd(nand);
+       u32 strength;
+       int i;
+
+       strength = avail_ecc_bytes * 8 / ECC_PARITY_BITS;
+
+       /* Find the closest supported ecc strength */
+       for (i = ARRAY_SIZE(mt7621_ecc_strength) - 1; i >= 0; i--) {
+               if (mt7621_ecc_strength[i] <= strength)
+                       break;
+       }
+
+       if (unlikely(i < 0)) {
+               pr_err("OOB size (%u) is not supported\n", mtd->oobsize);
+               return -EINVAL;
+       }
+
+       nand->ecc.strength = mt7621_ecc_strength[i];
+       nand->ecc.bytes =
+               DIV_ROUND_UP(nand->ecc.strength * ECC_PARITY_BITS, 8);
+
+       pr_debug("ECC strength adjusted to %u bits\n", nand->ecc.strength);
+
+       return i;
+}
+
+static int mt7621_nfc_set_spare_per_sector(struct mt7621_nfc *nfc)
+{
+       struct nand_chip *nand = &nfc->nand;
+       struct mtd_info *mtd = nand_to_mtd(nand);
+       u32 size;
+       int i;
+
+       size = nand->ecc.bytes + NFI_FDM_SIZE;
+
+       /* Find the closest supported spare size */
+       for (i = 0; i < ARRAY_SIZE(mt7621_nfi_spare_size); i++) {
+               if (mt7621_nfi_spare_size[i] >= size)
+                       break;
+       }
+
+       if (unlikely(i >= ARRAY_SIZE(mt7621_nfi_spare_size))) {
+               pr_err("OOB size (%u) is not supported\n", mtd->oobsize);
+               return -EINVAL;
+       }
+
+       nfc->spare_per_sector = mt7621_nfi_spare_size[i];
+
+       return i;
+}
+
+static int mt7621_nfc_ecc_init(struct mt7621_nfc *nfc)
+{
+       struct nand_chip *nand = &nfc->nand;
+       struct mtd_info *mtd = nand_to_mtd(nand);
+       u32 spare_per_sector, encode_block_size, decode_block_size;
+       u32 ecc_enccfg, ecc_deccfg;
+       int ecc_cap;
+
+       nand->ecc.options |= NAND_ECC_CUSTOM_PAGE_ACCESS;
+
+       nand->ecc.size = ECC_SECTOR_SIZE;
+       nand->ecc.steps = mtd->writesize / nand->ecc.size;
+
+       spare_per_sector = mtd->oobsize / nand->ecc.steps;
+
+       ecc_cap = mt7621_nfc_calc_ecc_strength(nfc,
+                                              spare_per_sector - NFI_FDM_SIZE);
+       if (ecc_cap < 0)
+               return ecc_cap;
+
+       /* Sector + FDM */
+       encode_block_size = (nand->ecc.size + NFI_FDM_SIZE) * 8;
+       ecc_enccfg = ecc_cap | (ENC_MODE_NFI << ENC_MODE_S) |
+                    (encode_block_size << ENC_CNFG_MSG_S);
+
+       /* Sector + FDM + ECC parity bits */
+       decode_block_size = ((nand->ecc.size + NFI_FDM_SIZE) * 8) +
+                           nand->ecc.strength * ECC_PARITY_BITS;
+       ecc_deccfg = ecc_cap | (DEC_MODE_NFI << DEC_MODE_S) |
+                    (decode_block_size << DEC_CS_S) |
+                    (DEC_CON_EL << DEC_CON_S) | DEC_EMPTY_EN;
+
+       mt7621_ecc_encoder_op(nfc, false);
+       ecc_write32(nfc, ECC_ENCCNFG, ecc_enccfg);
+
+       mt7621_ecc_decoder_op(nfc, false);
+       ecc_write32(nfc, ECC_DECCNFG, ecc_deccfg);
+
+       return 0;
+}
+
+static int mt7621_nfc_set_page_format(struct mt7621_nfc *nfc)
+{
+       struct nand_chip *nand = &nfc->nand;
+       struct mtd_info *mtd = nand_to_mtd(nand);
+       int i, spare_size;
+       u32 pagefmt;
+
+       spare_size = mt7621_nfc_set_spare_per_sector(nfc);
+       if (spare_size < 0)
+               return spare_size;
+
+       for (i = 0; i < ARRAY_SIZE(mt7621_nfi_page_size); i++) {
+               if (mt7621_nfi_page_size[i] == mtd->writesize)
+                       break;
+       }
+
+       if (unlikely(i >= ARRAY_SIZE(mt7621_nfi_page_size))) {
+               pr_err("Page size (%u) is not supported\n", mtd->writesize);
+               return -EINVAL;
+       }
+
+       pagefmt = i | (spare_size << PAGEFMT_SPARE_S) |
+                 (NFI_FDM_SIZE << PAGEFMT_FDM_S) |
+                 (NFI_FDM_SIZE << PAGEFMT_FDM_ECC_S);
+
+       nfi_write16(nfc, NFI_PAGEFMT, pagefmt);
+
+       return 0;
+}
+
+static int mt7621_nfc_attach_chip(struct nand_chip *nand)
+{
+       struct mt7621_nfc *nfc = nand_get_controller_data(nand);
+       int ret;
+
+       if (nand->options & NAND_BUSWIDTH_16) {
+               pr_err("16-bit buswidth is not supported");
+               return -EINVAL;
+       }
+
+       ret = mt7621_nfc_ecc_init(nfc);
+       if (ret)
+               return ret;
+
+       return mt7621_nfc_set_page_format(nfc);
+}
+
+static void mt7621_nfc_write_fdm(struct mt7621_nfc *nfc)
+{
+       struct nand_chip *nand = &nfc->nand;
+       u32 vall, valm;
+       u8 *oobptr;
+       int i, j;
+
+       for (i = 0; i < nand->ecc.steps; i++) {
+               vall = 0;
+               valm = 0;
+               oobptr = oob_fdm_ptr(nand, i);
+
+               for (j = 0; j < 4; j++)
+                       vall |= (u32)oobptr[j] << (j * 8);
+
+               for (j = 0; j < 4; j++)
+                       valm |= (u32)oobptr[j + 4] << ((j - 4) * 8);
+
+               nfi_write32(nfc, NFI_FDML(i), vall);
+               nfi_write32(nfc, NFI_FDMM(i), valm);
+       }
+}
+
+static void mt7621_nfc_read_sector_fdm(struct mt7621_nfc *nfc, u32 sect)
+{
+       struct nand_chip *nand = &nfc->nand;
+       u32 vall, valm;
+       u8 *oobptr;
+       int i;
+
+       vall = nfi_read32(nfc, NFI_FDML(sect));
+       valm = nfi_read32(nfc, NFI_FDMM(sect));
+       oobptr = oob_fdm_ptr(nand, sect);
+
+       for (i = 0; i < 4; i++)
+               oobptr[i] = (vall >> (i * 8)) & 0xff;
+
+       for (i = 0; i < 4; i++)
+               oobptr[i + 4] = (valm >> (i * 8)) & 0xff;
+}
+
+static int mt7621_nfc_read_page_hwecc(struct mtd_info *mtd,
+                                     struct nand_chip *nand, uint8_t *buf,
+                                     int oob_required, int page)
+{
+       struct mt7621_nfc *nfc = nand_get_controller_data(nand);
+       int bitflips = 0, ret = 0;
+       int rc, i;
+
+       nand_read_page_op(nand, page, 0, NULL, 0);
+
+       nfi_write16(nfc, NFI_CNFG, (CNFG_OP_CUSTOM << CNFG_OP_MODE_S) |
+                   CNFG_READ_MODE | CNFG_AUTO_FMT_EN | CNFG_HW_ECC_EN);
+
+       mt7621_ecc_decoder_op(nfc, true);
+
+       nfi_write16(nfc, NFI_CON,
+                   CON_NFI_BRD | (nand->ecc.steps << CON_NFI_SEC_S));
+
+       for (i = 0; i < nand->ecc.steps; i++) {
+               if (buf)
+                       mt7621_nfc_read_data(nfc, page_data_ptr(nand, buf, i),
+                                            nand->ecc.size);
+               else
+                       mt7621_nfc_read_data_discard(nfc, nand->ecc.size);
+
+               rc = mt7621_ecc_decoder_wait_done(nfc, i);
+
+               mt7621_nfc_read_sector_fdm(nfc, i);
+
+               if (rc < 0) {
+                       ret = -EIO;
+                       continue;
+               }
+
+               rc = mt7621_ecc_correct_check(nfc,
+                       buf ? page_data_ptr(nand, buf, i) : NULL,
+                       oob_fdm_ptr(nand, i), i);
+
+               if (rc < 0) {
+                       pr_warn("Uncorrectable ECC error at page %d step %d\n",
+                               page, i);
+                       bitflips = nand->ecc.strength + 1;
+                       mtd->ecc_stats.failed++;
+               } else {
+                       if (rc > bitflips)
+                               bitflips = rc;
+                       mtd->ecc_stats.corrected += rc;
+               }
+       }
+
+       mt7621_ecc_decoder_op(nfc, false);
+
+       nfi_write16(nfc, NFI_CON, 0);
+
+       if (ret < 0)
+               return ret;
+
+       return bitflips;
+}
+
+static int mt7621_nfc_read_page_raw(struct mtd_info *mtd,
+                                   struct nand_chip *nand, uint8_t *buf,
+                                   int oob_required, int page)
+{
+       struct mt7621_nfc *nfc = nand_get_controller_data(nand);
+       int i;
+
+       nand_read_page_op(nand, page, 0, NULL, 0);
+
+       nfi_write16(nfc, NFI_CNFG, (CNFG_OP_CUSTOM << CNFG_OP_MODE_S) |
+                   CNFG_READ_MODE);
+
+       nfi_write16(nfc, NFI_CON,
+                   CON_NFI_BRD | (nand->ecc.steps << CON_NFI_SEC_S));
+
+       for (i = 0; i < nand->ecc.steps; i++) {
+               /* Read data */
+               if (buf)
+                       mt7621_nfc_read_data(nfc, page_data_ptr(nand, buf, i),
+                                            nand->ecc.size);
+               else
+                       mt7621_nfc_read_data_discard(nfc, nand->ecc.size);
+
+               /* Read FDM */
+               mt7621_nfc_read_data(nfc, oob_fdm_ptr(nand, i), NFI_FDM_SIZE);
+
+               /* Read ECC parity data */
+               mt7621_nfc_read_data(nfc, oob_ecc_ptr(nfc, i),
+                                    nfc->spare_per_sector - NFI_FDM_SIZE);
+       }
+
+       nfi_write16(nfc, NFI_CON, 0);
+
+       return 0;
+}
+
+static int mt7621_nfc_read_oob_hwecc(struct mtd_info *mtd,
+                                    struct nand_chip *nand, int page)
+{
+       return mt7621_nfc_read_page_hwecc(mtd, nand, NULL, 1, page);
+}
+
+static int mt7621_nfc_read_oob_raw(struct mtd_info *mtd,
+                                  struct nand_chip *nand, int page)
+{
+       return mt7621_nfc_read_page_raw(mtd, nand, NULL, 1, page);
+}
+
+static int mt7621_nfc_check_empty_page(struct nand_chip *nand, const u8 *buf)
+{
+       struct mtd_info *mtd = nand_to_mtd(nand);
+       u8 *oobptr;
+       u32 i, j;
+
+       if (buf) {
+               for (i = 0; i < mtd->writesize; i++)
+                       if (buf[i] != 0xff)
+                               return 0;
+       }
+
+       for (i = 0; i < nand->ecc.steps; i++) {
+               oobptr = oob_fdm_ptr(nand, i);
+               for (j = 0; j < NFI_FDM_SIZE; j++)
+                       if (oobptr[j] != 0xff)
+                               return 0;
+       }
+
+       return 1;
+}
+
+static int mt7621_nfc_write_page_hwecc(struct mtd_info *mtd,
+                                      struct nand_chip *nand,
+                                      const u8 *buf, int oob_required,
+                                      int page)
+{
+       struct mt7621_nfc *nfc = nand_get_controller_data(nand);
+
+       if (mt7621_nfc_check_empty_page(nand, buf)) {
+               /*
+                * MT7621 ECC engine always generates parity code for input
+                * pages, even for empty pages. Doing so will write back ECC
+                * parity code to the oob region, which means such pages will
+                * no longer be empty pages.
+                *
+                * To avoid this, stop write operation if current page is an
+                * empty page.
+                */
+               return 0;
+       }
+
+       nand_prog_page_begin_op(nand, page, 0, NULL, 0);
+
+       nfi_write16(nfc, NFI_CNFG, (CNFG_OP_CUSTOM << CNFG_OP_MODE_S) |
+                  CNFG_AUTO_FMT_EN | CNFG_HW_ECC_EN);
+
+       mt7621_ecc_encoder_op(nfc, true);
+
+       mt7621_nfc_write_fdm(nfc);
+
+       nfi_write16(nfc, NFI_CON,
+                   CON_NFI_BWR | (nand->ecc.steps << CON_NFI_SEC_S));
+
+       if (buf)
+               mt7621_nfc_write_data(nfc, buf, mtd->writesize);
+       else
+               mt7621_nfc_write_data_empty(nfc, mtd->writesize);
+
+       mt7621_nfc_wait_write_completion(nfc, nand);
+
+       mt7621_ecc_encoder_op(nfc, false);
+
+       nfi_write16(nfc, NFI_CON, 0);
+
+       return nand_prog_page_end_op(nand);
+}
+
+static int mt7621_nfc_write_page_raw(struct mtd_info *mtd,
+                                    struct nand_chip *nand,
+                                    const u8 *buf, int oob_required,
+                                    int page)
+{
+       struct mt7621_nfc *nfc = nand_get_controller_data(nand);
+       int i;
+
+       nand_prog_page_begin_op(nand, page, 0, NULL, 0);
+
+       nfi_write16(nfc, NFI_CNFG, (CNFG_OP_CUSTOM << CNFG_OP_MODE_S));
+
+       nfi_write16(nfc, NFI_CON,
+                   CON_NFI_BWR | (nand->ecc.steps << CON_NFI_SEC_S));
+
+       for (i = 0; i < nand->ecc.steps; i++) {
+               /* Write data */
+               if (buf)
+                       mt7621_nfc_write_data(nfc, page_data_ptr(nand, buf, i),
+                                             nand->ecc.size);
+               else
+                       mt7621_nfc_write_data_empty(nfc, nand->ecc.size);
+
+               /* Write FDM */
+               mt7621_nfc_write_data(nfc, oob_fdm_ptr(nand, i),
+                                     NFI_FDM_SIZE);
+
+               /* Write dummy ECC parity data */
+               mt7621_nfc_write_data_empty(nfc, nfc->spare_per_sector -
+                                           NFI_FDM_SIZE);
+       }
+
+       mt7621_nfc_wait_write_completion(nfc, nand);
+
+       nfi_write16(nfc, NFI_CON, 0);
+
+       return nand_prog_page_end_op(nand);
+}
+
+static int mt7621_nfc_write_oob_hwecc(struct mtd_info *mtd,
+                                     struct nand_chip *nand, int page)
+{
+       return mt7621_nfc_write_page_hwecc(mtd, nand, NULL, 1, page);
+}
+
+static int mt7621_nfc_write_oob_raw(struct mtd_info *mtd,
+                                   struct nand_chip *nand, int page)
+{
+       return mt7621_nfc_write_page_raw(mtd, nand, NULL, 1, page);
+}
+
+static int mt7621_nfc_ooblayout_free(struct mtd_info *mtd, int section,
+                                    struct mtd_oob_region *oob_region)
+{
+       struct nand_chip *nand = mtd_to_nand(mtd);
+
+       if (section >= nand->ecc.steps)
+               return -ERANGE;
+
+       oob_region->length = NFI_FDM_SIZE - 1;
+       oob_region->offset = section * NFI_FDM_SIZE + 1;
+
+       return 0;
+}
+
+static int mt7621_nfc_ooblayout_ecc(struct mtd_info *mtd, int section,
+                                   struct mtd_oob_region *oob_region)
+{
+       struct nand_chip *nand = mtd_to_nand(mtd);
+
+       if (section)
+               return -ERANGE;
+
+       oob_region->offset = NFI_FDM_SIZE * nand->ecc.steps;
+       oob_region->length = mtd->oobsize - oob_region->offset;
+
+       return 0;
+}
+
+static const struct mtd_ooblayout_ops mt7621_nfc_ooblayout_ops = {
+       .rfree = mt7621_nfc_ooblayout_free,
+       .ecc = mt7621_nfc_ooblayout_ecc,
+};
+
+/*
+ * This function will override the default one which is not supposed to be
+ * used for ECC syndrome based pages.
+ */
+static int mt7621_nfc_block_bad(struct mtd_info *mtd, loff_t ofs)
+{
+       struct nand_chip *nand = mtd_to_nand(mtd);
+       struct mtd_oob_ops ops;
+       int ret, i = 0;
+       u16 bad;
+
+       memset(&ops, 0, sizeof(ops));
+       ops.oobbuf = (uint8_t *)&bad;
+       ops.ooboffs = nand->badblockpos;
+       if (nand->options & NAND_BUSWIDTH_16) {
+               ops.ooboffs &= ~0x01;
+               ops.ooblen = 2;
+       } else {
+               ops.ooblen = 1;
+       }
+       ops.mode = MTD_OPS_RAW;
+
+       /* Read from first/last page(s) if necessary */
+       if (nand->bbt_options & NAND_BBT_SCANLASTPAGE)
+               ofs += mtd->erasesize - mtd->writesize;
+
+       do {
+               ret = mtd_read_oob(mtd, ofs, &ops);
+               if (ret)
+                       return ret;
+
+               if (likely(nand->badblockbits == 8))
+                       ret = bad != 0xFF;
+               else
+                       ret = hweight8(bad) < nand->badblockbits;
+
+               i++;
+               ofs += mtd->writesize;
+       } while (!ret && (nand->bbt_options & NAND_BBT_SCAN2NDPAGE) && i < 2);
+
+       return ret;
+}
+
+static void mt7621_nfc_init_chip(struct mt7621_nfc *nfc)
+{
+       struct nand_chip *nand = &nfc->nand;
+       struct mtd_info *mtd;
+       int ret;
+
+       nand_set_controller_data(nand, (void *)nfc);
+
+       nand->options |= NAND_NO_SUBPAGE_WRITE;
+
+       nand->ecc.mode = NAND_ECC_HW_SYNDROME;
+       nand->ecc.read_page = mt7621_nfc_read_page_hwecc;
+       nand->ecc.read_page_raw = mt7621_nfc_read_page_raw;
+       nand->ecc.write_page = mt7621_nfc_write_page_hwecc;
+       nand->ecc.write_page_raw = mt7621_nfc_write_page_raw;
+       nand->ecc.read_oob = mt7621_nfc_read_oob_hwecc;
+       nand->ecc.read_oob_raw = mt7621_nfc_read_oob_raw;
+       nand->ecc.write_oob = mt7621_nfc_write_oob_hwecc;
+       nand->ecc.write_oob_raw = mt7621_nfc_write_oob_raw;
+
+       nand->dev_ready = mt7621_nfc_dev_ready;
+       nand->select_chip = mt7621_nfc_select_chip;
+       nand->write_byte = mt7621_nfc_write_byte;
+       nand->write_buf = mt7621_nfc_write_buf;
+       nand->read_byte = mt7621_nfc_read_byte;
+       nand->read_buf = mt7621_nfc_read_buf;
+       nand->cmd_ctrl = mt7621_nfc_cmd_ctrl;
+       nand->block_bad = mt7621_nfc_block_bad;
+
+       mtd = nand_to_mtd(nand);
+       mtd_set_ooblayout(mtd, &mt7621_nfc_ooblayout_ops);
+
+       /* Reset NFI master */
+       mt7621_nfc_hw_init(nfc);
+
+       ret = nand_scan_ident(mtd, 1, NULL);
+       if (ret)
+               return;
+
+       mt7621_nfc_attach_chip(nand);
+
+       ret = nand_scan_tail(mtd);
+       if (ret)
+               return;
+
+       nand_register(0, mtd);
+}
+
+void board_nand_init(void)
+{
+       nfc_dev.nfi_regs = (void __iomem *)CKSEG1ADDR(NFI_BASE);
+       nfc_dev.ecc_regs = (void __iomem *)CKSEG1ADDR(NFI_ECC_BASE);
+
+       mt7621_nfc_init_chip(&nfc_dev);
+}
-- 
2.17.1

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