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SubjectRe: [RESEND PATCH 2/5] mtd: rawnand: add NVIDIA Tegra NAND Flash controller driver
Hi Boris,

Thanks for the initial review! One small question below:

On 23.05.2018 16:18, Boris Brezillon wrote:
> Hi Stefan,
>
> On Tue, 22 May 2018 14:07:06 +0200
> Stefan Agner <stefan@agner.ch> wrote:
>> +
>> +struct tegra_nand {
>> + void __iomem *regs;
>> + struct clk *clk;
>> + struct gpio_desc *wp_gpio;
>> +
>> + struct nand_chip chip;
>> + struct device *dev;
>> +
>> + struct completion command_complete;
>> + struct completion dma_complete;
>> + bool last_read_error;
>> +
>> + dma_addr_t data_dma;
>> + void *data_buf;
>> + dma_addr_t oob_dma;
>> + void *oob_buf;
>> +
>> + int cur_chip;
>> +};
>
> This struct should be split in 2 structures: one representing the NAND
> controller and one representing the NAND chip:
>
> struct tegra_nand_controller {
> struct nand_hw_control base;
> void __iomem *regs;
> struct clk *clk;
> struct device *dev;
> struct completion command_complete;
> struct completion dma_complete;
> bool last_read_error;
> int cur_chip;
> };
>
> struct tegra_nand {
> struct nand_chip base;
> dma_addr_t data_dma;
> void *data_buf;
> dma_addr_t oob_dma;
> void *oob_buf;
> };

Is there a particular reason why you would leave DMA buffers in the chip
structure? It seems that is more a controller thing...

If I move them, then struct tegra_nand would be basically empty. Can I
just use struct nand_chip and have no driver specific chip abstraction?

--
Stefan

>
>> +
>> +static inline struct tegra_nand *to_tegra_nand(struct mtd_info *mtd)
>> +{
>> + struct nand_chip *chip = mtd_to_nand(mtd);
>> +
>> + return nand_get_controller_data(chip);
>
> then you can just do:
>
> return container_of(chip, struct tegra_nand, base);
>
>> +}
>> +
>> +static int tegra_nand_ooblayout_16_ecc(struct mtd_info *mtd, int section,
>> + struct mtd_oob_region *oobregion)
>> +{
>> + if (section > 0)
>> + return -ERANGE;
>> +
>> + oobregion->offset = 4;
>> + oobregion->length = 4;
>> +
>> + return 0;
>> +}
>> +
>> +static int tegra_nand_ooblayout_16_free(struct mtd_info *mtd, int section,
>> + struct mtd_oob_region *oobregion)
>> +{
>> + if (section > 0)
>> + return -ERANGE;
>> +
>> + oobregion->offset = 8;
>> + oobregion->length = 8;
>> +
>> + return 0;
>> +}
>
> ...
>
>> +
>> +static int tegra_nand_ooblayout_224_ecc(struct mtd_info *mtd, int section,
>> + struct mtd_oob_region *oobregion)
>> +{
>> + if (section > 0)
>> + return -ERANGE;
>> +
>> + oobregion->offset = 4;
>> + oobregion->length = 144;
>> +
>> + return 0;
>> +}
>> +
>> +static int tegra_nand_ooblayout_224_free(struct mtd_info *mtd, int section,
>> + struct mtd_oob_region *oobregion)
>> +{
>> + if (section > 0)
>> + return -ERANGE;
>> +
>> + oobregion->offset = 148;
>> + oobregion->length = 76;
>> +
>> + return 0;
>> +}
>> +
>> +static const struct mtd_ooblayout_ops tegra_nand_oob_224_ops = {
>> + .ecc = tegra_nand_ooblayout_224_ecc,
>> + .free = tegra_nand_ooblayout_224_free,
>> +};
>> +
>
> I'm pretty sure we can find a pattern here to avoid defining a new
> mtd_ooblayout_ops for each OOB size.
>
>> +static irqreturn_t tegra_nand_irq(int irq, void *data)
>> +{
>> + struct tegra_nand *nand = data;
>> + u32 isr, dma;
>> +
>> + isr = readl(nand->regs + ISR);
>> + dma = readl(nand->regs + DMA_CTRL);
>> + dev_dbg(nand->dev, "isr %08x\n", isr);
>> +
>> + if (!isr && !(dma & DMA_CTRL_IS_DONE))
>> + return IRQ_NONE;
>> +
>> + if (isr & ISR_CORRFAIL_ERR)
>> + nand->last_read_error = true;
>> +
>> + if (isr & ISR_CMD_DONE)
>> + complete(&nand->command_complete);
>> +
>> + if (isr & ISR_UND)
>> + dev_dbg(nand->dev, "FIFO underrun\n");
>> +
>> + if (isr & ISR_OVR)
>> + dev_dbg(nand->dev, "FIFO overrun\n");
>> +
>> + /* handle DMA interrupts */
>> + if (dma & DMA_CTRL_IS_DONE) {
>> + writel(dma, nand->regs + DMA_CTRL);
>> + complete(&nand->dma_complete);
>> + }
>> +
>> + /* clear interrupts */
>> + writel(isr, nand->regs + ISR);
>> +
>> + return IRQ_HANDLED;
>> +}
>> +
>> +static int tegra_nand_cmd(struct nand_chip *chip,
>> + const struct nand_subop *subop)
>> +{
>> + const struct nand_op_instr *instr;
>> + const struct nand_op_instr *instr_data_in = NULL;
>> + struct mtd_info *mtd = nand_to_mtd(chip);
>> + struct tegra_nand *nand = to_tegra_nand(mtd);
>> + unsigned int op_id = -1, trfr_in_sz = 0, trfr_out_sz = 0, offset = 0;
>> + bool first_cmd = true;
>> + bool force8bit;
>> + u32 cmd = 0;
>> + u32 value;
>> +
>> + for (op_id = 0; op_id < subop->ninstrs; op_id++) {
>> + unsigned int naddrs, i;
>> + const u8 *addrs;
>> + u32 addr1 = 0, addr2 = 0;
>> +
>> + instr = &subop->instrs[op_id];
>> +
>> + switch (instr->type) {
>> + case NAND_OP_CMD_INSTR:
>> + if (first_cmd) {
>> + cmd |= CMD_CLE;
>> + writel(instr->ctx.cmd.opcode, nand->regs + CMD_1);
>> + } else {
>> + cmd |= CMD_SEC_CMD;
>> + writel(instr->ctx.cmd.opcode, nand->regs + CMD_2);
>> + }
>> + first_cmd = false;
>> + break;
>> + case NAND_OP_ADDR_INSTR:
>> + offset = nand_subop_get_addr_start_off(subop, op_id);
>> + naddrs = nand_subop_get_num_addr_cyc(subop, op_id);
>> + addrs = &instr->ctx.addr.addrs[offset];
>> +
>> + cmd |= CMD_ALE | CMD_ALE_SIZE(naddrs);
>> + for (i = 0; i < min_t(unsigned int, 4, naddrs); i++)
>> + addr1 |= *addrs++ << (8 * i);
>> + naddrs -= i;
>> + for (i = 0; i < min_t(unsigned int, 4, naddrs); i++)
>> + addr2 |= *addrs++ << (8 * i);
>> + writel(addr1, nand->regs + ADDR_1);
>> + writel(addr2, nand->regs + ADDR_2);
>> + break;
>> +
>> + case NAND_OP_DATA_IN_INSTR:
>> + trfr_in_sz = nand_subop_get_data_len(subop, op_id);
>> + offset = nand_subop_get_data_start_off(subop, op_id);
>> +
>> + cmd |= CMD_TRANS_SIZE(trfr_in_sz) | CMD_PIO | CMD_RX | CMD_A_VALID;
>> +
>> + instr_data_in = instr;
>> + break;
>> +
>> + case NAND_OP_DATA_OUT_INSTR:
>> + trfr_out_sz = nand_subop_get_data_len(subop, op_id);
>> + offset = nand_subop_get_data_start_off(subop, op_id);
>> + trfr_out_sz = min_t(size_t, trfr_out_sz, 4);
>> +
>> + cmd |= CMD_TRANS_SIZE(trfr_out_sz) | CMD_PIO | CMD_TX | CMD_A_VALID;
>> +
>> + memcpy(&value, instr->ctx.data.buf.out + offset, trfr_out_sz);
>> + writel(value, nand->regs + RESP);
>> +
>> + break;
>> + case NAND_OP_WAITRDY_INSTR:
>> + cmd |= CMD_RBSY_CHK;
>> + break;
>> +
>> + }
>> + }
>> +
>> +
>> + cmd |= CMD_GO | CMD_CE(nand->cur_chip);
>> + writel(cmd, nand->regs + CMD);
>> + wait_for_completion(&nand->command_complete);
>> +
>> + if (instr_data_in) {
>> + u32 value;
>> + size_t n = min_t(size_t, trfr_in_sz, 4);
>> +
>> + value = readl(nand->regs + RESP);
>> + memcpy(instr_data_in->ctx.data.buf.in + offset, &value, n);
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static const struct nand_op_parser tegra_nand_op_parser = NAND_OP_PARSER(
>> + NAND_OP_PARSER_PATTERN(tegra_nand_cmd,
>> + NAND_OP_PARSER_PAT_CMD_ELEM(true),
>> + NAND_OP_PARSER_PAT_ADDR_ELEM(true, 8),
>> + NAND_OP_PARSER_PAT_CMD_ELEM(true),
>> + NAND_OP_PARSER_PAT_WAITRDY_ELEM(true)),
>> + NAND_OP_PARSER_PATTERN(tegra_nand_cmd,
>> + NAND_OP_PARSER_PAT_DATA_OUT_ELEM(false, 4)),
>> + NAND_OP_PARSER_PATTERN(tegra_nand_cmd,
>> + NAND_OP_PARSER_PAT_CMD_ELEM(true),
>> + NAND_OP_PARSER_PAT_ADDR_ELEM(true, 8),
>> + NAND_OP_PARSER_PAT_CMD_ELEM(true),
>> + NAND_OP_PARSER_PAT_WAITRDY_ELEM(true),
>> + NAND_OP_PARSER_PAT_DATA_IN_ELEM(true, 4)),
>> + );
>> +
>> +static int tegra_nand_exec_op(struct nand_chip *chip,
>> + const struct nand_operation *op,
>> + bool check_only)
>> +{
>> + return nand_op_parser_exec_op(chip, &tegra_nand_op_parser, op,
>> + check_only);
>> +}
>
> Missing empty line here.
>
>> +static void tegra_nand_select_chip(struct mtd_info *mtd, int chip)
>> +{
>> + struct tegra_nand *nand = to_tegra_nand(mtd);
>> +
>> + nand->cur_chip = chip;
>> +}
>
> ...
>
>> +
>> +static void tegra_nand_setup_chiptiming(struct tegra_nand *nand)
>> +{
>> + struct nand_chip *chip = &nand->chip;
>> + int mode;
>> +
>> + mode = onfi_get_async_timing_mode(chip);
>> + if (mode == ONFI_TIMING_MODE_UNKNOWN)
>> + mode = chip->onfi_timing_mode_default;
>> + else
>> + mode = fls(mode);
>> +
>> + tegra_nand_setup_timing(nand, mode);
>
> Hm, you shouldn't do that. Let the core select the timing mode for you,
> and just implement the ->setup_data_interface() hook.
>
>> +}
>> +
>> +static int tegra_nand_probe(struct platform_device *pdev)
>> +{
>> + struct reset_control *rst;
>> + struct tegra_nand *nand;
>> + struct nand_chip *chip;
>> + struct mtd_info *mtd;
>> + struct resource *res;
>> + unsigned long value;
>> + int irq, err = 0;
>> +
>> + nand = devm_kzalloc(&pdev->dev, sizeof(*nand), GFP_KERNEL);
>> + if (!nand)
>> + return -ENOMEM;
>> +
>> + nand->dev = &pdev->dev;
>> +
>> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> + nand->regs = devm_ioremap_resource(&pdev->dev, res);
>> + if (IS_ERR(nand->regs))
>> + return PTR_ERR(nand->regs);
>> +
>> + irq = platform_get_irq(pdev, 0);
>> + err = devm_request_irq(&pdev->dev, irq, tegra_nand_irq, 0,
>> + dev_name(&pdev->dev), nand);
>> + if (err)
>> + return err;
>> +
>> + rst = devm_reset_control_get(&pdev->dev, "nand");
>> + if (IS_ERR(rst))
>> + return PTR_ERR(rst);
>> +
>> + nand->clk = devm_clk_get(&pdev->dev, "nand");
>> + if (IS_ERR(nand->clk))
>> + return PTR_ERR(nand->clk);
>> +
>> + nand->wp_gpio = gpiod_get_optional(&pdev->dev, "wp-gpios",
>> + GPIOD_OUT_HIGH);
>> + if (IS_ERR(nand->wp_gpio))
>> + return PTR_ERR(nand->wp_gpio);
>> +
>> + err = clk_prepare_enable(nand->clk);
>> + if (err)
>> + return err;
>> +
>> + reset_control_assert(rst);
>> + udelay(2);
>> + reset_control_deassert(rst);
>> +
>> + value = HWSTATUS_RDSTATUS_MASK(1) | HWSTATUS_RDSTATUS_VALUE(0) |
>> + HWSTATUS_RBSY_MASK(NAND_STATUS_READY) |
>> + HWSTATUS_RBSY_VALUE(NAND_STATUS_READY);
>> + writel(NAND_CMD_STATUS, nand->regs + HWSTATUS_CMD);
>> + writel(value, nand->regs + HWSTATUS_MASK);
>> +
>> + init_completion(&nand->command_complete);
>> + init_completion(&nand->dma_complete);
>> +
>> + /* clear interrupts */
>> + value = readl(nand->regs + ISR);
>> + writel(value, nand->regs + ISR);
>> +
>> + writel(DMA_CTRL_IS_DONE, nand->regs + DMA_CTRL);
>> +
>> + /* enable interrupts */
>> + value = IER_UND | IER_OVR | IER_CMD_DONE | IER_ECC_ERR | IER_GIE;
>> + writel(value, nand->regs + IER);
>> +
>> + /* reset config */
>> + writel(0, nand->regs + CFG);
>> +
>> + chip = &nand->chip;
>> + mtd = nand_to_mtd(chip);
>> +
>> + mtd->dev.parent = &pdev->dev;
>> + mtd->name = "tegra_nand";
>> + mtd->owner = THIS_MODULE;
>> +
>> + nand_set_flash_node(chip, pdev->dev.of_node);
>> + nand_set_controller_data(chip, nand);
>> +
>> + chip->options = NAND_NO_SUBPAGE_WRITE;
>> + chip->exec_op = tegra_nand_exec_op;
>> + chip->select_chip = tegra_nand_select_chip;
>> + tegra_nand_setup_timing(nand, 0);
>> +
>> + err = nand_scan_ident(mtd, 1, NULL);
>> + if (err)
>> + goto err_disable_clk;
>> +
>> + if (chip->bbt_options & NAND_BBT_USE_FLASH)
>> + chip->bbt_options |= NAND_BBT_NO_OOB;
>> +
>> + nand->data_buf = dmam_alloc_coherent(&pdev->dev, mtd->writesize,
>> + &nand->data_dma, GFP_KERNEL);
>> + if (!nand->data_buf) {
>> + err = -ENOMEM;
>> + goto err_disable_clk;
>> + }
>> +
>> + nand->oob_buf = dmam_alloc_coherent(&pdev->dev, mtd->oobsize,
>> + &nand->oob_dma, GFP_KERNEL);
>> + if (!nand->oob_buf) {
>> + err = -ENOMEM;
>> + goto err_disable_clk;
>> + }
>> +
>> + chip->ecc.mode = NAND_ECC_HW;
>> + chip->ecc.size = 512;
>> + chip->ecc.read_page = tegra_nand_read_page;
>> + chip->ecc.write_page = tegra_nand_write_page;
>
> I'd like to have raw accessors implemented here.
>
> That was just a quick review focusing mainly on architectural issues so
> that you can start working on a v2.
>
> Regards,
>
> Boris

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