Dear Sascha,
Thank you for your reply.
On 2024/9/18 下午 06:58, Sascha Hauer wrote:
Hi,
The driver has a few minor whitespace issues, please run through
checkpatch.pl to catch them.
I will fix it.
Some more things inline.
On Wed, Sep 18, 2024 at 09:03:08AM +0000, Hui-Ping Chen wrote:
Nuvoton MA35 SoCs NAND Flash Interface Controller
supports 2kiB, 4kiB and 8kiB page size, and up to
8-bit, 12-bit, and 24-bit hardware ECC calculation
circuit to protect data.
Signed-off-by: Hui-Ping Chen <hpchen0nvt@xxxxxxxxx>
---
drivers/mtd/nand/raw/Kconfig | 8 +
drivers/mtd/nand/raw/Makefile | 1 +
drivers/mtd/nand/raw/nuvoton_ma35d1_nand.c | 935 +++++++++++++++++++++
3 files changed, 944 insertions(+)
create mode 100644 drivers/mtd/nand/raw/nuvoton_ma35d1_nand.c
+#define SKIP_SPARE_BYTES 4
Unused, please drop.
I will remove it.
+static int ma35_nfi_ecc_check(struct nand_chip *chip, unsigned long addr)
+{
+ struct ma35_nand_info *nand = nand_get_controller_data(chip);
+ struct mtd_info *mtd = nand_to_mtd(chip);
+ int status, i, j, nchunks = 0;
status should be unsigned.
Okay, I will modify it.
+ int report_err = 0;
+ int err_cnt = 0;
+
+ nchunks = mtd->writesize / chip->ecc.steps;
+ if (nchunks < 4)
+ nchunks = 1;
+ else
+ nchunks /= 4;
+
+ for (j = 0; j < nchunks; j++) {
+ status = readl(nand->regs + MA35_NFI_REG_NANDECCES0 + j*4);
+ if (!status)
+ continue;
+
+ for (i = 0; i < 4; i++) {
+ if (!(status & ECC_STATUS_MASK)) {
+ /* No error */
+ status >>= 8;
+ continue;
+
+ } else if ((status & ECC_STATUS_MASK) == 0x01) {
+ /* Correctable error */
+ err_cnt = (status >> 2) & ECC_ERR_CNT_MASK;
+ dev_warn(nand->dev, "nchunks (%d, %d) have %d error!\n",
+ j, i, err_cnt);
Correctable bitflips are expected. Please don't spam the log with it.
I will remove it.
+ ma35_nfi_correct(nand, j*4+i, err_cnt, (u8 *)addr);
+ report_err += err_cnt;
+
+ } else {
+ /* uncorrectable error */
+ dev_warn(nand->dev, "uncorrectable error! 0x%4x\n", status);
+ return -1;
+ }
+ status >>= 8;
+ }
+ }
+ return report_err;
There are a few things wrong here. Your chip->ecc.read_page op must
return the maximum number of bitflips occured on a subpage while
reading a page.
To archieve this I suggest you fix the return value of this function
accordingly and call it from chip->ecc.read_page rather than from the
interrupt handler.
Nevertheless mtd->ecc_stats.corrected counts the total number of
bitflips, so you must handle this counter in this function.
See rk_nfc_read_page_hwecc() as an example of a driver which gets it
right.
The background is that we have to rewrite the page once one ECC block
hits a critical bitflip limit. A whole page might be fine when the
bitflips are evenly distributed across the subpages, but it's not when
all bitflips are occur in a single subpage.
I will refer to rk_nfc_read_page_hwecc() and then rewrite it.
+static int ma35_nand_do_write(struct nand_chip *chip, const u8 *addr, u32 len)
+{
+ struct ma35_nand_info *nand = nand_get_controller_data(chip);
+ struct mtd_info *mtd = nand_to_mtd(chip);
+ dma_addr_t dma_addr;
+ int ret = 0, i;
+ u32 val, reg;
+
+ ma35_nand_target_enable(nand);
+
+ if (len != mtd->writesize) {
+ for (i = 0; i < len; i++)
+ writel(addr[i], nand->regs + MA35_NFI_REG_NANDDATA);
+ ma35_nand_target_disable(nand);
+ return ret;
+ }
+
+ /* Check the DMA status before enabling the DMA */
+ ret = readl_poll_timeout(nand->regs + MA35_NFI_REG_DMACTL, val,
+ !(val & DMA_BUSY), 50, HZ/2);
+ if (ret)
+ dev_warn(nand->dev, "dma busy\n");
+
+ /* Reinitial dmac */
+ ma35_nand_dmac_init(nand);
The function name already says it and the comment doesn't offer any
additional information. Please drop such comments.
I will remove it.
+
+ writel(mtd->oobsize, nand->regs + MA35_NFI_REG_NANDRACTL);
+
+ /* setup and start DMA using dma_addr */
+ writel(INT_DMA, nand->regs + MA35_NFI_REG_NANDINTEN);
+ /* To mark this page as dirty. */
+ reg = readl(nand->regs + MA35_NFI_REG_NANDRA0);
+ if (reg & 0xffff0000)
+ writel(reg & 0xffff, nand->regs + MA35_NFI_REG_NANDRA0);
+
+ /* Fill dma_addr */
+ dma_addr = dma_map_single(nand->dev, (void *)addr, len, DMA_TO_DEVICE);
+ dma_sync_single_for_device(nand->dev, dma_addr, len, DMA_TO_DEVICE);
+ ret = dma_mapping_error(nand->dev, dma_addr);
+ if (ret) {
+ dev_err(nand->dev, "dma mapping error\n");
+ return -EINVAL;
+ }
Call dma_sync_single_for_device() after you have checked for an error
with dma_mapping_error().
That said, I think calling dma_sync_single_for_device() after
dma_map_single() is unnecessary.
I will modify the calling sequence.
+
+ writel((unsigned long)dma_addr, nand->regs + MA35_NFI_REG_DMASA);
+ writel(readl(nand->regs + MA35_NFI_REG_NANDCTL) | DMA_W_EN,
+ nand->regs + MA35_NFI_REG_NANDCTL);
+ ret = wait_for_completion_timeout(&nand->complete, msecs_to_jiffies(1000));
+ if (!ret) {
+ dev_err(nand->dev, "write timeout\n");
+ ret = -ETIMEDOUT;
+ }
+
+ dma_unmap_single(nand->dev, dma_addr, len, DMA_TO_DEVICE);
+
+ ma35_nand_target_disable(nand);
+
+ return ret;
+}
+
+static int ma35_nand_do_read(struct nand_chip *chip, const u8 *addr, u32 len)
The addr argument shouldn't be const. You are supposed to write to this
buffer and you actually do so.
I will change this argument to u8 *.
+{
+ struct ma35_nand_info *nand = nand_get_controller_data(chip);
+ struct mtd_info *mtd = nand_to_mtd(chip);
+ u8 *ptr = (u8 *)addr;
+ dma_addr_t dma_addr;
+ int ret = 0, i;
+ u32 val;
+
+ ma35_nand_target_enable(nand);
+
+ if (len != mtd->writesize) {
+ for (i = 0; i < len; i++)
+ *(ptr+i) = (u8)readl(nand->regs + MA35_NFI_REG_NANDDATA);
+ ma35_nand_target_disable(nand);
+ return ret;
Just return 0 here. It's easier to read than having to look up the
initialization value.
I will change it to return 0 directly.
+ }
+
+ /* Check the DMA status before enabling the DMA */
+ ret = readl_poll_timeout(nand->regs + MA35_NFI_REG_DMACTL, val,
+ !(val & DMA_BUSY), 50, HZ/2);
+ if (ret)
+ dev_warn(nand->dev, "dma busy\n");
+
+ /* Reinitial dmac */
+ ma35_nand_dmac_init(nand);
+
+ writel(mtd->oobsize, nand->regs + MA35_NFI_REG_NANDRACTL);
+
+ /* setup and start DMA using dma_addr */
+ dma_addr = dma_map_single(nand->dev, (void *)addr, len, DMA_FROM_DEVICE);
+ ret = dma_mapping_error(nand->dev, dma_addr);
+ if (ret) {
+ dev_err(nand->dev, "dma mapping error\n");
+ return -EINVAL;
+ }
+ nand->dma_buf = (u8 *)addr;
+ nand->dma_addr = dma_addr;
+
+ writel((unsigned long)dma_addr, nand->regs + MA35_NFI_REG_DMASA);
+ writel(readl(nand->regs + MA35_NFI_REG_NANDCTL) | DMA_R_EN,
+ nand->regs + MA35_NFI_REG_NANDCTL);
+ ret = wait_for_completion_timeout(&nand->complete, msecs_to_jiffies(1000));
+ if (!ret) {
+ dev_err(nand->dev, "read timeout\n");
+ ret = -ETIMEDOUT;
+ }
+
+ dma_sync_single_for_cpu(nand->dev, dma_addr, len, DMA_FROM_DEVICE);
+ dma_unmap_single(nand->dev, dma_addr, len, DMA_FROM_DEVICE);
No need to call dma_sync_single_for_cpu() before dma_unmap_single().
I will remove it.
+
+ ma35_nand_target_disable(nand);
+
+ return ret;
+}
+
+
+static int ma35_nand_write_page_hwecc(struct nand_chip *chip, const u8 *buf,
+ int oob_required, int page)
+{
+ struct mtd_info *mtd = nand_to_mtd(chip);
+ u8 *ecc_calc = chip->ecc.calc_buf;
Make this a void * to get rid of the explicit casting below.
I will modify it.
+
+ ma35_clear_spare(chip, mtd->oobsize);
+ ma35_write_spare(chip, mtd->oobsize - chip->ecc.total, (u32 *)chip->oob_poi);
+
+ nand_prog_page_begin_op(chip, page, 0, buf, mtd->writesize);
+ nand_prog_page_end_op(chip);
+
+ /* Copy parity code in NANDRA to calc */
+ ma35_read_spare(chip, chip->ecc.total, (u32 *)ecc_calc,
+ mtd->oobsize - chip->ecc.total);
+
+ /* Copy parity code in calc to oob_poi */
+ memcpy((void *)(chip->oob_poi + (mtd->oobsize - chip->ecc.total)),
+ (void *)ecc_calc, chip->ecc.total);
+
+ return 0;
+}
+
+static irqreturn_t ma35_nand_irq(int irq, void *id)
+{
+ struct ma35_nand_info *nand = (struct ma35_nand_info *)id;
+ struct mtd_info *mtd = nand_to_mtd(&nand->chip);
+ int stat = 0;
+ u32 isr;
+
+ spin_lock(&nand->dma_lock);
+
+ isr = readl(nand->regs + MA35_NFI_REG_NANDINTSTS);
+ if (isr & INT_ECC) {
+ dma_sync_single_for_cpu(nand->dev, nand->dma_addr, mtd->writesize,
+ DMA_FROM_DEVICE);
+ stat = ma35_nfi_ecc_check(&nand->chip, (unsigned long)nand->dma_buf);
nand->dma_buf already is a pointer which you cast to unisgned long here
and back to a pointer in ma35_nfi_ecc_check(). ma35_nfi_ecc_check()
should take a poiner instead.
I will fix it.
+ if (stat < 0) {
+ mtd->ecc_stats.failed++;
+ writel(DMA_RST | DMA_EN, nand->regs + MA35_NFI_REG_DMACTL);
+ writel(readl(nand->regs + MA35_NFI_REG_NANDCTL) | SWRST,
+ nand->regs + MA35_NFI_REG_NANDCTL);
+ } else if (stat > 0) {
+ mtd->ecc_stats.corrected += stat; /* Add corrected bit count */
+ }
+ writel(INT_ECC, nand->regs + MA35_NFI_REG_NANDINTSTS);
+ }
+ if (isr & INT_DMA) {
+ writel(INT_DMA, nand->regs + MA35_NFI_REG_NANDINTSTS);
+ complete(&nand->complete);
+ }
+ spin_unlock(&nand->dma_lock);
+
+ return IRQ_HANDLED;
+}
+
+static int ma35_nfc_exec_op(struct nand_chip *chip,
+ const struct nand_operation *op,
+ bool check_only)
+{
+ struct ma35_nand_info *nand = nand_get_controller_data(chip);
+ u32 i, reg;
+ int ret = 0;
+
+ if (check_only)
+ return 0;
+
+ ma35_nand_target_enable(nand);
+ reg = readl(nand->regs + MA35_NFI_REG_NANDINTSTS);
+ reg |= INT_RB0;
+ writel(reg, nand->regs + MA35_NFI_REG_NANDINTSTS);
+
+ for (i = 0; i < op->ninstrs; i++) {
+ ret = ma35_nfc_exec_instr(chip, &op->instrs[i]);
+ if (ret)
+ break;
+ }
The way ma35_nand_target_[en|dis]able() is called looks inconsistent.
This function calls ma35_nand_target_enable(), so I would expect that
the corresponding ma35_nand_target_disable() should be called here as
well.
ma35_nand_do_read() is called from here which has its own call to
ma35_nand_target_enable(), but it doesn't call ma35_nand_target_disable()
from all of its return pathes.
Okay. I will check and fix it.
+
+ ret = devm_request_irq(&pdev->dev, nand->irq, ma35_nand_irq,
+ IRQF_TRIGGER_HIGH, "ma35d1-nand", nand);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to request NAND irq\n");
+ clk_disable_unprepare(nand->clk);
You used devm_clk_get_enabled(), so this will be done automatically.
I will remove it.
+ return -ENXIO;
+ }
+
+ nand->chip.controller = &nand->controller;
+ platform_set_drvdata(pdev, nand);
+
+ chip->options |= NAND_NO_SUBPAGE_WRITE | NAND_USES_DMA;
+
+ /* set default mode in case dt entry is missing */
+ chip->ecc.engine_type = NAND_ECC_ENGINE_TYPE_ON_HOST;
+
+ chip->ecc.write_page = ma35_nand_write_page_hwecc;
+ chip->ecc.read_page = ma35_nand_read_page_hwecc;
+ chip->ecc.read_oob = ma35_nand_read_oob_hwecc;
+
+ mtd = nand_to_mtd(chip);
+ mtd->priv = chip;
+ mtd->owner = THIS_MODULE;
+ mtd->dev.parent = &pdev->dev;
+
+ writel(NAND_EN, nand->regs + MA35_NFI_REG_GCTL);
+
+ ret = nand_scan(chip, 1);
+ if (ret)
+ return ret;
+
+ ret = mtd_device_register(mtd, NULL, 0);
+ if (ret) {
+ nand_cleanup(chip);
+ devm_kfree(&pdev->dev, nand);
Unnecessary free. Drop it.
I will remove it.
+ return ret;
+ }
+
+ return ret;
+}
+
+static void ma35_nand_remove(struct platform_device *pdev)
+{
+ struct ma35_nand_info *nand = platform_get_drvdata(pdev);
+ int ret;
+
+ devm_free_irq(&pdev->dev, nand->irq, nand);
devm_ is a mechanism to let resources be freed automatically. There's
normally no need to do this manually.
Okay. I will check and remove it.
Sascha
Best regards,
Hui-Ping Chen
