[PATCH v3 14/22] mtd: nand: mxic-ecc: Add Macronix external ECC engine support

Miquel Raynal
2021-12-07T09:53:14Z

Some SPI-NAND chips do not support on-die ECC. For these chips,
correction must apply on the SPI controller end. In order to avoid
doing all the calculations by software, Macronix provides a specific
engine that can offload the intensive work.

Add Macronix ECC engine support, this engine can work in conjunction
with a SPI controller and a raw NAND controller, it can be pipelined
or external and supports linear and syndrome layouts.

Right now the simplest configuration is supported: SPI controller
external and linear ECC engine.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
drivers/mtd/nand/Kconfig | 6 +
drivers/mtd/nand/Makefile | 1 +
drivers/mtd/nand/ecc-mxic.c | 692 ++++++++++++++++++++++++++++++++++++
3 files changed, 699 insertions(+)
create mode 100644 drivers/mtd/nand/ecc-mxic.c

diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
index b40455234cbd..8431292ff49d 100644
--- a/drivers/mtd/nand/Kconfig
+++ b/drivers/mtd/nand/Kconfig
@@ -46,6 +46,12 @@ config MTD_NAND_ECC_SW_BCH
ECC codes. They are used with NAND devices requiring more than 1 bit
of error correction.

+config MTD_NAND_ECC_MXIC
+ bool "Macronix external hardware ECC engine"
+ select MTD_NAND_ECC
+ help
+ This enables support for the hardware ECC engine from Macronix.
+
endmenu

endmenu
diff --git a/drivers/mtd/nand/Makefile b/drivers/mtd/nand/Makefile
index 1c0b46960eb1..a4e6b7ae0614 100644
--- a/drivers/mtd/nand/Makefile
+++ b/drivers/mtd/nand/Makefile
@@ -10,3 +10,4 @@ obj-y += spi/
nandcore-$(CONFIG_MTD_NAND_ECC) += ecc.o
nandcore-$(CONFIG_MTD_NAND_ECC_SW_HAMMING) += ecc-sw-hamming.o
nandcore-$(CONFIG_MTD_NAND_ECC_SW_BCH) += ecc-sw-bch.o
+nandcore-$(CONFIG_MTD_NAND_ECC_MXIC) += ecc-mxic.o
diff --git a/drivers/mtd/nand/ecc-mxic.c b/drivers/mtd/nand/ecc-mxic.c
new file mode 100644
index 000000000000..ea88a411ed70
--- /dev/null
+++ b/drivers/mtd/nand/ecc-mxic.c
@@ -0,0 +1,692 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Support for Macronix external hardware ECC engine for NAND devices, also
+ * called DPE for Data Processing Engine.
+ *
+ * Copyright © 2019 Macronix
+ * Author: Miquel Raynal <miquel.raynal@bootlin.com>
+ */
+
+#include <linux/dma-mapping.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/nand.h>
+#include <linux/mutex.h>
+#include <linux/of_device.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+/* DPE Configuration */
+#define DP_CONFIG 0x00
+#define ECC_EN BIT(0)
+#define ECC_TYP(idx) (((idx) << 3) & GENMASK(6, 3))
+/* DPE Interrupt Status */
+#define INTRPT_STS 0x04
+#define TRANS_CMPLT BIT(0)
+#define SDMA_MAIN BIT(1)
+#define SDMA_SPARE BIT(2)
+#define ECC_ERR BIT(3)
+#define TO_SPARE BIT(4)
+#define TO_MAIN BIT(5)
+/* DPE Interrupt Status Enable */
+#define INTRPT_STS_EN 0x08
+/* DPE Interrupt Signal Enable */
+#define INTRPT_SIG_EN 0x0C
+/* Host Controller Configuration */
+#define HC_CONFIG 0x10
+#define MEM2MEM BIT(4) /* TRANS_TYP_IO in the spec */
+#define ECC_PACKED 0 /* LAYOUT_TYP_INTEGRATED in the spec */
+#define ECC_INTERLEAVED BIT(2) /* LAYOUT_TYP_DISTRIBUTED in the spec */
+#define BURST_TYP_FIXED 0
+#define BURST_TYP_INCREASING BIT(0)
+/* Host Controller Slave Address */
+#define HC_SLV_ADDR 0x14
+/* ECC Chunk Size */
+#define CHUNK_SIZE 0x20
+/* Main Data Size */
+#define MAIN_SIZE 0x24
+/* Spare Data Size */
+#define SPARE_SIZE 0x28
+#define META_SZ(reg) ((reg) & GENMASK(7, 0))
+#define PARITY_SZ(reg) (((reg) & GENMASK(15, 8)) >> 8)
+#define RSV_SZ(reg) (((reg) & GENMASK(23, 16)) >> 16)
+#define SPARE_SZ(reg) ((reg) >> 24)
+/* ECC Chunk Count */
+#define CHUNK_CNT 0x30
+/* SDMA Control */
+#define SDMA_CTRL 0x40
+#define WRITE_NAND 0
+#define READ_NAND BIT(1)
+#define CONT_NAND BIT(29)
+#define CONT_SYSM BIT(30) /* Continue System Memory? */
+#define SDMA_STRT BIT(31)
+/* SDMA Address of Main Data */
+#define SDMA_MAIN_ADDR 0x44
+/* SDMA Address of Spare Data */
+#define SDMA_SPARE_ADDR 0x48
+/* DPE Version Number */
+#define DP_VER 0xD0
+#define DP_VER_OFFSET 16
+
+/* Status bytes between each chunk of spare data */
+#define STAT_BYTES 4
+#define NO_ERR 0x00
+#define MAX_CORR_ERR 0x28
+#define UNCORR_ERR 0xFE
+#define ERASED_CHUNK 0xFF
+
+struct mxic_ecc_engine {
+ struct device *dev;
+ void __iomem *regs;
+ int irq;
+ struct completion complete;
+ struct nand_ecc_engine external_engine;
+ struct mutex lock;
+};
+
+struct mxic_ecc_ctx {
+ /* ECC machinery */
+ unsigned int data_step_sz;
+ unsigned int oob_step_sz;
+ unsigned int parity_sz;
+ unsigned int meta_sz;
+ u8 *status;
+ int steps;
+
+ /* DMA boilerplate */
+ struct nand_ecc_req_tweak_ctx req_ctx;
+ u8 *oobwithstat;
+ struct scatterlist sg[2];
+ struct nand_page_io_req *req;
+};
+
+static struct mxic_ecc_engine *ext_ecc_eng_to_mxic(struct nand_ecc_engine *eng)
+{
+ return container_of(eng, struct mxic_ecc_engine, external_engine);
+}
+
+static struct mxic_ecc_engine *nand_to_mxic(struct nand_device *nand)
+{
+ struct nand_ecc_engine *eng = nand->ecc.engine;
+
+ return ext_ecc_eng_to_mxic(eng);
+}
+
+static int mxic_ecc_ooblayout_ecc(struct mtd_info *mtd, int section,
+ struct mtd_oob_region *oobregion)
+{
+ struct nand_device *nand = mtd_to_nanddev(mtd);
+ struct mxic_ecc_ctx *ctx = nand_to_ecc_ctx(nand);
+
+ if (section < 0 || section >= ctx->steps)
+ return -ERANGE;
+
+ oobregion->offset = (section * ctx->oob_step_sz) + ctx->meta_sz;
+ oobregion->length = ctx->parity_sz;
+
+ return 0;
+}
+
+static int mxic_ecc_ooblayout_free(struct mtd_info *mtd, int section,
+ struct mtd_oob_region *oobregion)
+{
+ struct nand_device *nand = mtd_to_nanddev(mtd);
+ struct mxic_ecc_ctx *ctx = nand_to_ecc_ctx(nand);
+
+ if (section < 0 || section >= ctx->steps)
+ return -ERANGE;
+
+ if (!section) {
+ oobregion->offset = 2;
+ oobregion->length = ctx->meta_sz - 2;
+ } else {
+ oobregion->offset = section * ctx->oob_step_sz;
+ oobregion->length = ctx->meta_sz;
+ }
+
+ return 0;
+}
+
+static const struct mtd_ooblayout_ops mxic_ecc_ooblayout_ops = {
+ .ecc = mxic_ecc_ooblayout_ecc,
+ .free = mxic_ecc_ooblayout_free,
+};
+
+static void mxic_ecc_disable_engine(struct mxic_ecc_engine *mxic)
+{
+ u32 reg;
+
+ reg = readl(mxic->regs + DP_CONFIG);
+ reg &= ~ECC_EN;
+ writel(reg, mxic->regs + DP_CONFIG);
+}
+
+static void mxic_ecc_enable_engine(struct mxic_ecc_engine *mxic)
+{
+ u32 reg;
+
+ reg = readl(mxic->regs + DP_CONFIG);
+ reg |= ECC_EN;
+ writel(reg, mxic->regs + DP_CONFIG);
+}
+
+static void mxic_ecc_disable_int(struct mxic_ecc_engine *mxic)
+{
+ writel(0, mxic->regs + INTRPT_SIG_EN);
+}
+
+static void mxic_ecc_enable_int(struct mxic_ecc_engine *mxic)
+{
+ writel(TRANS_CMPLT, mxic->regs + INTRPT_SIG_EN);
+}
+
+static irqreturn_t mxic_ecc_isr(int irq, void *dev_id)
+{
+ struct mxic_ecc_engine *mxic = dev_id;
+ u32 sts;
+
+ sts = readl(mxic->regs + INTRPT_STS);
+ if (!sts)
+ return IRQ_NONE;
+
+ if (sts & TRANS_CMPLT)
+ complete(&mxic->complete);
+
+ writel(sts, mxic->regs + INTRPT_STS);
+
+ return IRQ_HANDLED;
+}
+
+static int mxic_ecc_init_ctx(struct nand_device *nand, struct device *dev)
+{
+ struct mxic_ecc_engine *mxic = nand_to_mxic(nand);
+ struct nand_ecc_props *conf = &nand->ecc.ctx.conf;
+ struct nand_ecc_props *reqs = &nand->ecc.requirements;
+ struct nand_ecc_props *user = &nand->ecc.user_conf;
+ struct mtd_info *mtd = nanddev_to_mtd(nand);
+ int step_size = 0, strength = 0, desired_correction = 0, steps, idx;
+ int possible_strength[] = {4, 8, 40, 48};
+ int spare_size[] = {32, 32, 96, 96};
+ struct mxic_ecc_ctx *ctx;
+ u32 spare_reg;
+ int ret;
+
+ ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
+ if (!ctx)
+ return -ENOMEM;
+
+ nand->ecc.ctx.priv = ctx;
+
+ /* Only large page NAND chips may use BCH */
+ if (mtd->oobsize < 64) {
+ pr_err("BCH cannot be used with small page NAND chips\n");
+ return -EINVAL;
+ }
+
+ mtd_set_ooblayout(mtd, &mxic_ecc_ooblayout_ops);
+
+ /* Enable all status bits */
+ writel(TRANS_CMPLT | SDMA_MAIN | SDMA_SPARE | ECC_ERR |
+ TO_SPARE | TO_MAIN, mxic->regs + INTRPT_STS_EN);
+
+ /* Configure the correction depending on the NAND device topology */
+ if (user->step_size && user->strength) {
+ step_size = user->step_size;
+ strength = user->strength;
+ } else if (reqs->step_size && reqs->strength) {
+ step_size = reqs->step_size;
+ strength = reqs->strength;
+ }
+
+ if (step_size && strength) {
+ steps = mtd->writesize / step_size;
+ desired_correction = steps * strength;
+ }
+
+ /* Step size is fixed to 1kiB, strength may vary (4 possible values) */
+ conf->step_size = SZ_1K;
+ steps = mtd->writesize / conf->step_size;
+
+ ctx->status = devm_kzalloc(dev, steps * sizeof(u8), GFP_KERNEL);
+ if (!ctx->status)
+ return -ENOMEM;
+
+ if (desired_correction) {
+ strength = desired_correction / steps;
+
+ for (idx = 0; idx < ARRAY_SIZE(possible_strength); idx++)
+ if (possible_strength[idx] >= strength)
+ break;
+
+ idx = min_t(unsigned int, idx,
+ ARRAY_SIZE(possible_strength) - 1);
+ } else {
+ /* Missing data, maximize the correction */
+ idx = ARRAY_SIZE(possible_strength) - 1;
+ }
+
+ /* Tune the selected strength until it fits in the OOB area */
+ for (; idx >= 0; idx--) {
+ if (spare_size[idx] * steps <= mtd->oobsize)
+ break;
+ }
+
+ /* This engine cannot be used with this NAND device */
+ if (idx < 0)
+ return -EINVAL;
+
+ /* Configure the engine for the desired strength */
+ writel(ECC_TYP(idx), mxic->regs + DP_CONFIG);
+ conf->strength = possible_strength[idx];
+ spare_reg = readl(mxic->regs + SPARE_SIZE);
+
+ ctx->steps = steps;
+ ctx->data_step_sz = mtd->writesize / steps;
+ ctx->oob_step_sz = mtd->oobsize / steps;
+ ctx->parity_sz = PARITY_SZ(spare_reg);
+ ctx->meta_sz = META_SZ(spare_reg);
+
+ /* Ensure buffers will contain enough bytes to store the STAT_BYTES */
+ ctx->req_ctx.oob_buffer_size = nanddev_per_page_oobsize(nand) +
+ (ctx->steps * STAT_BYTES);
+ ret = nand_ecc_init_req_tweaking(&ctx->req_ctx, nand);
+ if (ret)
+ return ret;
+
+ ctx->oobwithstat = kmalloc(mtd->oobsize + (ctx->steps * STAT_BYTES),
+ GFP_KERNEL);
+ if (!ctx->oobwithstat) {
+ ret = -ENOMEM;
+ goto cleanup_req_tweak;
+ }
+
+ sg_init_table(ctx->sg, 2);
+
+ /* Configuration dump and sanity checks */
+ dev_err(dev, "DPE version number: %d\n",
+ readl(mxic->regs + DP_VER) >> DP_VER_OFFSET);
+ dev_err(dev, "Chunk size: %d\n", readl(mxic->regs + CHUNK_SIZE));
+ dev_err(dev, "Main size: %d\n", readl(mxic->regs + MAIN_SIZE));
+ dev_err(dev, "Spare size: %d\n", SPARE_SZ(spare_reg));
+ dev_err(dev, "Rsv size: %ld\n", RSV_SZ(spare_reg));
+ dev_err(dev, "Parity size: %d\n", ctx->parity_sz);
+ dev_err(dev, "Meta size: %d\n", ctx->meta_sz);
+
+ if ((ctx->meta_sz + ctx->parity_sz + RSV_SZ(spare_reg)) !=
+ SPARE_SZ(spare_reg)) {
+ dev_err(dev, "Wrong OOB configuration: %d + %d + %ld != %d\n",
+ ctx->meta_sz, ctx->parity_sz, RSV_SZ(spare_reg),
+ SPARE_SZ(spare_reg));
+ ret = -EINVAL;
+ goto free_oobwithstat;
+ }
+
+ if (ctx->oob_step_sz != SPARE_SZ(spare_reg)) {
+ dev_err(dev, "Wrong OOB configuration: %d != %d\n",
+ ctx->oob_step_sz, SPARE_SZ(spare_reg));
+ ret = -EINVAL;
+ goto free_oobwithstat;
+ }
+
+ return 0;
+
+free_oobwithstat:
+ kfree(ctx->oobwithstat);
+cleanup_req_tweak:
+ nand_ecc_cleanup_req_tweaking(&ctx->req_ctx);
+
+ return ret;
+}
+
+static int mxic_ecc_init_ctx_external(struct nand_device *nand)
+{
+ struct mxic_ecc_engine *mxic = nand_to_mxic(nand);
+ struct device *dev = nand->ecc.engine->dev;
+ int ret;
+
+ dev_info(dev, "Macronix ECC engine in external mode\n");
+
+ ret = mxic_ecc_init_ctx(nand, dev);
+ if (ret)
+ return ret;
+
+ /* Trigger each step manually */
+ writel(1, mxic->regs + CHUNK_CNT);
+ writel(BURST_TYP_INCREASING | ECC_PACKED | MEM2MEM,
+ mxic->regs + HC_CONFIG);
+
+ return 0;
+}
+
+static void mxic_ecc_cleanup_ctx(struct nand_device *nand)
+{
+ struct mxic_ecc_ctx *ctx = nand_to_ecc_ctx(nand);
+
+ if (ctx) {
+ nand_ecc_cleanup_req_tweaking(&ctx->req_ctx);
+ kfree(ctx->oobwithstat);
+ }
+}
+
+static int mxic_ecc_data_xfer_wait_for_completion(struct mxic_ecc_engine *mxic)
+{
+ u32 val;
+ int ret;
+
+ if (mxic->irq) {
+ reinit_completion(&mxic->complete);
+ mxic_ecc_enable_int(mxic);
+ ret = wait_for_completion_timeout(&mxic->complete,
+ msecs_to_jiffies(1000));
+ mxic_ecc_disable_int(mxic);
+ } else {
+ ret = readl_poll_timeout(mxic->regs + INTRPT_STS, val,
+ val & TRANS_CMPLT, 10, USEC_PER_SEC);
+ writel(val, mxic->regs + INTRPT_STS);
+ }
+
+ if (ret) {
+ dev_err(mxic->dev, "Timeout on data xfer completion (sts 0x%08x)\n", val);
+ return -ETIMEDOUT;
+ }
+
+ return 0;
+}
+
+static int mxic_ecc_process_data(struct mxic_ecc_engine *mxic,
+ unsigned int direction)
+{
+ unsigned int dir = (direction == NAND_PAGE_READ) ?
+ READ_NAND : WRITE_NAND;
+ int ret;
+
+ mxic_ecc_enable_engine(mxic);
+
+ /* Trigger processing */
+ writel(SDMA_STRT | dir, mxic->regs + SDMA_CTRL);
+
+ /* Wait for completion */
+ ret = mxic_ecc_data_xfer_wait_for_completion(mxic);
+
+ mxic_ecc_disable_engine(mxic);
+
+ return ret;
+}
+
+static void mxic_ecc_extract_status_bytes(struct mxic_ecc_ctx *ctx)
+{
+ u8 *buf = ctx->oobwithstat;
+ int next_stat_pos;
+ int step;
+
+ /* Extract the ECC status */
+ for (step = 0; step < ctx->steps; step++) {
+ next_stat_pos = ctx->oob_step_sz +
+ ((STAT_BYTES + ctx->oob_step_sz) * step);
+
+ ctx->status[step] = buf[next_stat_pos];
+ }
+}
+
+static void mxic_ecc_reconstruct_oobbuf(struct mxic_ecc_ctx *ctx,
+ u8 *dst, const u8 *src)
+{
+ int step;
+
+ /* Reconstruct the OOB buffer linearly (without the ECC status bytes) */
+ for (step = 0; step < ctx->steps; step++)
+ memcpy(dst + (step * ctx->oob_step_sz),
+ src + (step * (ctx->oob_step_sz + STAT_BYTES)),
+ ctx->oob_step_sz);
+}
+
+static void mxic_ecc_add_room_in_oobbuf(struct mxic_ecc_ctx *ctx,
+ u8 *dst, const u8 *src)
+{
+ int step;
+
+ /* Add some space in the OOB buffer for the status bytes */
+ for (step = 0; step < ctx->steps; step++)
+ memcpy(dst + (step * (ctx->oob_step_sz + STAT_BYTES)),
+ src + (step * ctx->oob_step_sz),
+ ctx->oob_step_sz);
+}
+
+static int mxic_ecc_count_biterrs(struct mxic_ecc_engine *mxic,
+ struct nand_device *nand)
+{
+ struct mxic_ecc_ctx *ctx = nand_to_ecc_ctx(nand);
+ struct mtd_info *mtd = nanddev_to_mtd(nand);
+ struct device *dev = mxic->dev;
+ unsigned int max_bf = 0;
+ bool failure = false;
+ int step;
+
+ for (step = 0; step < ctx->steps; step++) {
+ u8 stat = ctx->status[step];
+
+ if (stat == NO_ERR) {
+ dev_dbg(dev, "ECC step %d: no error\n", step);
+ } else if (stat == ERASED_CHUNK) {
+ dev_dbg(dev, "ECC step %d: erased\n", step);
+ } else if (stat == UNCORR_ERR || stat > MAX_CORR_ERR) {
+ dev_dbg(dev, "ECC step %d: uncorrectable\n", step);
+ mtd->ecc_stats.failed++;
+ failure = true;
+ } else {
+ dev_dbg(dev, "ECC step %d: %d bits corrected\n",
+ step, stat);
+ max_bf = max_t(unsigned int, max_bf, stat);
+ mtd->ecc_stats.corrected += stat;
+ }
+ }
+
+ return failure ? -EBADMSG : max_bf;
+}
+
+/* External ECC engine helpers */
+static int mxic_ecc_prepare_io_req_external(struct nand_device *nand,
+ struct nand_page_io_req *req)
+{
+ struct mxic_ecc_engine *mxic = nand_to_mxic(nand);
+ struct mxic_ecc_ctx *ctx = nand_to_ecc_ctx(nand);
+ struct mtd_info *mtd = nanddev_to_mtd(nand);
+ int offset, nents, step, ret;
+
+ if (req->mode == MTD_OPS_RAW)
+ return 0;
+
+ nand_ecc_tweak_req(&ctx->req_ctx, req);
+ ctx->req = req;
+
+ if (req->type == NAND_PAGE_READ)
+ return 0;
+
+ mxic_ecc_add_room_in_oobbuf(ctx, ctx->oobwithstat,
+ ctx->req->oobbuf.out);
+
+ sg_set_buf(&ctx->sg[0], req->databuf.out, req->datalen);
+ sg_set_buf(&ctx->sg[1], ctx->oobwithstat,
+ req->ooblen + (ctx->steps * STAT_BYTES));
+
+ nents = dma_map_sg(mxic->dev, ctx->sg, 2, DMA_BIDIRECTIONAL);
+ if (!nents)
+ return -EINVAL;
+
+ mutex_lock(&mxic->lock);
+
+ for (step = 0; step < ctx->steps; step++) {
+ writel(sg_dma_address(&ctx->sg[0]) + (step * ctx->data_step_sz),
+ mxic->regs + SDMA_MAIN_ADDR);
+ writel(sg_dma_address(&ctx->sg[1]) + (step * (ctx->oob_step_sz + STAT_BYTES)),
+ mxic->regs + SDMA_SPARE_ADDR);
+ ret = mxic_ecc_process_data(mxic, ctx->req->type);
+ if (ret)
+ break;
+ }
+
+ mutex_unlock(&mxic->lock);
+
+ dma_unmap_sg(mxic->dev, ctx->sg, 2, DMA_BIDIRECTIONAL);
+
+ /* Retrieve the calculated ECC bytes */
+ for (step = 0; step < ctx->steps; step++) {
+ offset = ctx->meta_sz + (step * ctx->oob_step_sz);
+ mtd_ooblayout_get_eccbytes(mtd,
+ (u8 *)ctx->req->oobbuf.out + offset,
+ ctx->oobwithstat + (step * STAT_BYTES),
+ step * ctx->parity_sz,
+ ctx->parity_sz);
+ }
+
+ return ret;
+}
+
+static int mxic_ecc_finish_io_req_external(struct nand_device *nand,
+ struct nand_page_io_req *req)
+{
+ struct mxic_ecc_engine *mxic = nand_to_mxic(nand);
+ struct mxic_ecc_ctx *ctx = nand_to_ecc_ctx(nand);
+ int nents, step, ret;
+
+ if (req->mode == MTD_OPS_RAW)
+ return 0;
+
+ if (req->type == NAND_PAGE_WRITE) {
+ nand_ecc_restore_req(&ctx->req_ctx, req);
+ return 0;
+ }
+
+ /* Copy the OOB buffer and add room for the ECC engine status bytes */
+ mxic_ecc_add_room_in_oobbuf(ctx, ctx->oobwithstat, ctx->req->oobbuf.in);
+
+ sg_set_buf(&ctx->sg[0], req->databuf.in, req->datalen);
+ sg_set_buf(&ctx->sg[1], ctx->oobwithstat,
+ req->ooblen + (ctx->steps * STAT_BYTES));
+ nents = dma_map_sg(mxic->dev, ctx->sg, 2, DMA_BIDIRECTIONAL);
+ if (!nents)
+ return -EINVAL;
+
+ mutex_lock(&mxic->lock);
+
+ for (step = 0; step < ctx->steps; step++) {
+ writel(sg_dma_address(&ctx->sg[0]) + (step * ctx->data_step_sz),
+ mxic->regs + SDMA_MAIN_ADDR);
+ writel(sg_dma_address(&ctx->sg[1]) + (step * (ctx->oob_step_sz + STAT_BYTES)),
+ mxic->regs + SDMA_SPARE_ADDR);
+ ret = mxic_ecc_process_data(mxic, ctx->req->type);
+ if (ret)
+ break;
+ }
+
+ mutex_unlock(&mxic->lock);
+
+ dma_unmap_sg(mxic->dev, ctx->sg, 2, DMA_BIDIRECTIONAL);
+
+ /* Extract the status bytes and reconstruct the buffer */
+ mxic_ecc_extract_status_bytes(ctx);
+ mxic_ecc_reconstruct_oobbuf(ctx, ctx->req->oobbuf.in, ctx->oobwithstat);
+
+ nand_ecc_restore_req(&ctx->req_ctx, req);
+
+ return mxic_ecc_count_biterrs(mxic, nand);
+}
+
+static struct nand_ecc_engine_ops mxic_ecc_engine_external_ops = {
+ .init_ctx = mxic_ecc_init_ctx_external,
+ .cleanup_ctx = mxic_ecc_cleanup_ctx,
+ .prepare_io_req = mxic_ecc_prepare_io_req_external,
+ .finish_io_req = mxic_ecc_finish_io_req_external,
+};
+
+static int mxic_ecc_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct mxic_ecc_engine *mxic;
+ int ret;
+
+ mxic = devm_kzalloc(&pdev->dev, sizeof(*mxic), GFP_KERNEL);
+ if (!mxic)
+ return -ENOMEM;
+
+ mxic->dev = &pdev->dev;
+
+ /*
+ * Both memory regions for the ECC engine itself and the AXI slave
+ * address are mandatory.
+ */
+ mxic->regs = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(mxic->regs)) {
+ dev_err(&pdev->dev, "Missing memory region\n");
+ return PTR_ERR(mxic->regs);
+ }
+
+ mxic_ecc_disable_engine(mxic);
+ mxic_ecc_disable_int(mxic);
+
+ /* IRQ is optional yet much more efficient */
+ mxic->irq = platform_get_irq_byname_optional(pdev, "ecc-engine");
+ if (mxic->irq > 0) {
+ ret = devm_request_irq(&pdev->dev, mxic->irq, mxic_ecc_isr, 0,
+ "mxic-ecc", mxic);
+ if (ret)
+ return ret;
+ } else {
+ dev_info(dev, "Invalid or missing IRQ, fallback to polling\n");
+ mxic->irq = 0;
+ }
+
+ mutex_init(&mxic->lock);
+
+ /*
+ * In external mode, the device is the ECC engine. In pipelined mode,
+ * the device is the host controller. The device is used to match the
+ * right ECC engine based on the DT properties.
+ */
+ mxic->external_engine.dev = &pdev->dev;
+ mxic->external_engine.integration = NAND_ECC_ENGINE_INTEGRATION_EXTERNAL;
+ mxic->external_engine.ops = &mxic_ecc_engine_external_ops;
+
+ nand_ecc_register_on_host_hw_engine(&mxic->external_engine);
+
+ platform_set_drvdata(pdev, mxic);
+
+ return 0;
+}
+
+static int mxic_ecc_remove(struct platform_device *pdev)
+{
+ struct mxic_ecc_engine *mxic = platform_get_drvdata(pdev);
+
+ nand_ecc_unregister_on_host_hw_engine(&mxic->external_engine);
+
+ return 0;
+}
+
+static const struct of_device_id mxic_ecc_of_ids[] = {
+ {
+ .compatible = "mxicy,nand-ecc-engine-rev3",
+ },
+ { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, mxic_ecc_of_ids);
+
+static struct platform_driver mxic_ecc_driver = {
+ .driver = {
+ .name = "mxic-nand-ecc-engine",
+ .of_match_table = mxic_ecc_of_ids,
+ },
+ .probe = mxic_ecc_probe,
+ .remove = mxic_ecc_remove,
+};
+module_platform_driver(mxic_ecc_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Miquel Raynal <miquel.raynal@bootlin.com>");
+MODULE_DESCRIPTION("Macronix NAND hardware ECC controller");