[Patch v3 2/5] mtd: nand: add NVIDIA Tegra NAND Flash controller driver
Lucas Stach
dev at lynxeye.de
Wed Jul 22 13:42:40 PDT 2015
Am Dienstag, den 21.07.2015, 14:27 -0700 schrieb Brian Norris:
> Hi Lucas,
>
> On Sun, May 10, 2015 at 08:29:59PM +0200, Lucas Stach wrote:
> > Add support for the NAND flash controller found on NVIDIA
> > Tegra 2/3 SoCs.
> >
> > Signed-off-by: Thierry Reding <thierry.reding at avionic-design.de>
> > Signed-off-by: Lucas Stach <dev at lynxeye.de>
> > Reviewed-by: Stefan Agner <stefan at agner.ch>
> > ---
> > v2:
> > - remove Tegra 3 compatible
> > - remove useless part_probes
> > - don't store irq number
> > - use gpiod API instead of deprecated of_gpios
> > - don't store reset
> > - correct TIMING_TCS mask
> > - simplify irq handler
> > - correct timing calculations
> > - don't store buswidth
> > - drop compile test
> > - correct ECC handling
> >
> > v3:
> > - remove superfluous NAND cap setting
> > - correct ECC layout
> > - don't flag ECC error for erased pages
>
> ^^ So you approached a tricky subject here :) more below
>
> > - make MTD device name a bit human friendlier
> > - mark subpage writes as unsupported
> > - parse BBT on flash property
> > ---
> > MAINTAINERS | 6 +
> > drivers/mtd/nand/Kconfig | 6 +
> > drivers/mtd/nand/Makefile | 1 +
> > drivers/mtd/nand/tegra_nand.c | 801 ++++++++++++++++++++++++++++++++++++++++++
> > 4 files changed, 814 insertions(+)
> > create mode 100644 drivers/mtd/nand/tegra_nand.c
> >
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 781e099..7e5551f 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -9747,6 +9747,12 @@ M: Laxman Dewangan <ldewangan at nvidia.com>
> > S: Supported
> > F: drivers/input/keyboard/tegra-kbc.c
> >
> > +TEGRA NAND DRIVER
> > +M: Lucas Stach <dev at lynxeye.de>
> > +S: Maintained
> > +F: Documentation/devicetree/bindings/mtd/nvidia,tegra20-nand.txt
> > +F: drivers/mtd/nand/tegra_nand.c
>
> Thanks for doing this.
>
> > +
> > TEGRA PWM DRIVER
> > M: Thierry Reding <thierry.reding at gmail.com>
> > S: Supported
> > diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
> > index 5897d8d..2696418 100644
> > --- a/drivers/mtd/nand/Kconfig
> > +++ b/drivers/mtd/nand/Kconfig
> > @@ -530,4 +530,10 @@ config MTD_NAND_HISI504
> > help
> > Enables support for NAND controller on Hisilicon SoC Hip04.
> >
> > +config MTD_NAND_TEGRA
> > + tristate "Support for NAND on NVIDIA Tegra"
> > + depends on ARCH_TEGRA
>
> Is this a strict depends? Maybe relax to the following at least:
>
> depends on ARCH_TEGRA || COMPILE_TEST
>
> > + help
> > + Enables support for NAND flash on NVIDIA Tegra SoC based boards.
> > +
> > endif # MTD_NAND
> > diff --git a/drivers/mtd/nand/Makefile b/drivers/mtd/nand/Makefile
> > index 582bbd05..3228e6e 100644
> > --- a/drivers/mtd/nand/Makefile
> > +++ b/drivers/mtd/nand/Makefile
> > @@ -52,5 +52,6 @@ obj-$(CONFIG_MTD_NAND_XWAY) += xway_nand.o
> > obj-$(CONFIG_MTD_NAND_BCM47XXNFLASH) += bcm47xxnflash/
> > obj-$(CONFIG_MTD_NAND_SUNXI) += sunxi_nand.o
> > obj-$(CONFIG_MTD_NAND_HISI504) += hisi504_nand.o
> > +obj-$(CONFIG_MTD_NAND_TEGRA) += tegra_nand.o
> >
> > nand-objs := nand_base.o nand_bbt.o nand_timings.o
> > diff --git a/drivers/mtd/nand/tegra_nand.c b/drivers/mtd/nand/tegra_nand.c
> > new file mode 100644
> > index 0000000..20ea1f1
> > --- /dev/null
> > +++ b/drivers/mtd/nand/tegra_nand.c
> > @@ -0,0 +1,801 @@
> > +/*
> > + * Copyright (C) 2014-2015 Lucas Stach <dev at lynxeye.de>
> > + * Copyright (C) 2012 Avionic Design GmbH
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License version 2 as
> > + * published by the Free Software Foundation.
> > + */
> > +
> > +#include <linux/clk.h>
> > +#include <linux/completion.h>
> > +#include <linux/delay.h>
> > +#include <linux/dma-mapping.h>
> > +#include <linux/err.h>
> > +#include <linux/gpio/consumer.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/io.h>
> > +#include <linux/module.h>
> > +#include <linux/mtd/nand.h>
> > +#include <linux/mtd/partitions.h>
> > +#include <linux/of_mtd.h>
> > +#include <linux/of.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/reset.h>
> > +
> > +#define CMD 0x00
> > +#define CMD_GO (1 << 31)
> > +#define CMD_CLE (1 << 30)
> > +#define CMD_ALE (1 << 29)
> > +#define CMD_PIO (1 << 28)
> > +#define CMD_TX (1 << 27)
> > +#define CMD_RX (1 << 26)
> > +#define CMD_SEC_CMD (1 << 25)
> > +#define CMD_AFT_DAT (1 << 24)
> > +#define CMD_TRANS_SIZE(x) (((x) & 0xf) << 20)
> > +#define CMD_A_VALID (1 << 19)
> > +#define CMD_B_VALID (1 << 18)
> > +#define CMD_RD_STATUS_CHK (1 << 17)
> > +#define CMD_RBSY_CHK (1 << 16)
> > +#define CMD_CE(x) (1 << (8 + ((x) & 0x7)))
> > +#define CMD_CLE_SIZE(x) (((x) & 0x3) << 4)
> > +#define CMD_ALE_SIZE(x) (((x) & 0xf) << 0)
> > +
> > +#define STATUS 0x04
> > +
> > +#define ISR 0x08
> > +#define ISR_UND (1 << 7)
> > +#define ISR_OVR (1 << 6)
> > +#define ISR_CMD_DONE (1 << 5)
> > +#define ISR_ECC_ERR (1 << 4)
> > +
> > +#define IER 0x0c
> > +#define IER_ERR_TRIG_VAL(x) (((x) & 0xf) << 16)
> > +#define IER_UND (1 << 7)
> > +#define IER_OVR (1 << 6)
> > +#define IER_CMD_DONE (1 << 5)
> > +#define IER_ECC_ERR (1 << 4)
> > +#define IER_GIE (1 << 0)
> > +
> > +#define CFG 0x10
> > +#define CFG_HW_ECC (1 << 31)
> > +#define CFG_ECC_SEL (1 << 30)
> > +#define CFG_ERR_COR (1 << 29)
> > +#define CFG_PIPE_EN (1 << 28)
> > +#define CFG_TVAL_4 (0 << 24)
> > +#define CFG_TVAL_6 (1 << 24)
> > +#define CFG_TVAL_8 (2 << 24)
> > +#define CFG_SKIP_SPARE (1 << 23)
> > +#define CFG_BUS_WIDTH_8 (0 << 21)
> > +#define CFG_BUS_WIDTH_16 (1 << 21)
> > +#define CFG_COM_BSY (1 << 20)
> > +#define CFG_PS_256 (0 << 16)
> > +#define CFG_PS_512 (1 << 16)
> > +#define CFG_PS_1024 (2 << 16)
> > +#define CFG_PS_2048 (3 << 16)
> > +#define CFG_PS_4096 (4 << 16)
> > +#define CFG_SKIP_SPARE_SIZE_4 (0 << 14)
> > +#define CFG_SKIP_SPARE_SIZE_8 (1 << 14)
> > +#define CFG_SKIP_SPARE_SIZE_12 (2 << 14)
> > +#define CFG_SKIP_SPARE_SIZE_16 (3 << 14)
> > +#define CFG_TAG_BYTE_SIZE(x) ((x) & 0xff)
> > +
> > +#define TIMING_1 0x14
> > +#define TIMING_TRP_RESP(x) (((x) & 0xf) << 28)
> > +#define TIMING_TWB(x) (((x) & 0xf) << 24)
> > +#define TIMING_TCR_TAR_TRR(x) (((x) & 0xf) << 20)
> > +#define TIMING_TWHR(x) (((x) & 0xf) << 16)
> > +#define TIMING_TCS(x) (((x) & 0x3) << 14)
> > +#define TIMING_TWH(x) (((x) & 0x3) << 12)
> > +#define TIMING_TWP(x) (((x) & 0xf) << 8)
> > +#define TIMING_TRH(x) (((x) & 0xf) << 4)
> > +#define TIMING_TRP(x) (((x) & 0xf) << 0)
> > +
> > +#define RESP 0x18
> > +
> > +#define TIMING_2 0x1c
> > +#define TIMING_TADL(x) ((x) & 0xf)
> > +
> > +#define CMD_1 0x20
> > +#define CMD_2 0x24
> > +#define ADDR_1 0x28
> > +#define ADDR_2 0x2c
> > +
> > +#define DMA_CTRL 0x30
> > +#define DMA_CTRL_GO (1 << 31)
> > +#define DMA_CTRL_IN (0 << 30)
> > +#define DMA_CTRL_OUT (1 << 30)
> > +#define DMA_CTRL_PERF_EN (1 << 29)
> > +#define DMA_CTRL_IE_DONE (1 << 28)
> > +#define DMA_CTRL_REUSE (1 << 27)
> > +#define DMA_CTRL_BURST_1 (2 << 24)
> > +#define DMA_CTRL_BURST_4 (3 << 24)
> > +#define DMA_CTRL_BURST_8 (4 << 24)
> > +#define DMA_CTRL_BURST_16 (5 << 24)
> > +#define DMA_CTRL_IS_DONE (1 << 20)
> > +#define DMA_CTRL_EN_A (1 << 2)
> > +#define DMA_CTRL_EN_B (1 << 1)
> > +
> > +#define DMA_CFG_A 0x34
> > +#define DMA_CFG_B 0x38
> > +
> > +#define FIFO_CTRL 0x3c
> > +#define FIFO_CTRL_CLR_ALL (1 << 3)
> > +
> > +#define DATA_PTR 0x40
> > +#define TAG_PTR 0x44
> > +#define ECC_PTR 0x48
> > +
> > +#define DEC_STATUS 0x4c
> > +#define DEC_STATUS_A_ECC_FAIL (1 << 1)
> > +#define DEC_STATUS_ERR_COUNT_MASK 0x00ff0000
> > +#define DEC_STATUS_ERR_COUNT_SHIFT 16
> > +
> > +#define HWSTATUS_CMD 0x50
> > +#define HWSTATUS_MASK 0x54
> > +#define HWSTATUS_RDSTATUS_MASK(x) (((x) & 0xff) << 24)
> > +#define HWSTATUS_RDSTATUS_VALUE(x) (((x) & 0xff) << 16)
> > +#define HWSTATUS_RBSY_MASK(x) (((x) & 0xff) << 8)
> > +#define HWSTATUS_RBSY_VALUE(x) (((x) & 0xff) << 0)
> > +
> > +struct tegra_nand {
> > + void __iomem *regs;
> > + struct clk *clk;
> > + struct gpio_desc *wp_gpio;
> > +
> > + struct nand_chip chip;
> > + struct mtd_info mtd;
> > + struct device *dev;
> > +
> > + struct completion command_complete;
> > + struct completion dma_complete;
> > +
> > + dma_addr_t data_dma;
> > + void *data_buf;
> > + dma_addr_t oob_dma;
> > + void *oob_buf;
> > +
> > + int cur_chip;
> > +};
> > +
> > +static inline struct tegra_nand *to_tegra_nand(struct mtd_info *mtd)
> > +{
> > + return container_of(mtd, struct tegra_nand, mtd);
> > +}
> > +
> > +static struct nand_ecclayout tegra_nand_oob_16 = {
> > + .eccbytes = 4,
> > + .eccpos = { 4, 5, 6, 7 },
> > + .oobfree = {
> > + { .offset = 8, . length = 8 }
> > + }
> > +};
> > +
> > +static struct nand_ecclayout tegra_nand_oob_64 = {
> > + .eccbytes = 36,
> > + .eccpos = {
> > + 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,
> > + 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35,
> > + 36, 37, 38, 39
> > + },
> > + .oobfree = {
> > + { .offset = 40, .length = 24 }
> > + }
> > +};
> > +
> > +static struct nand_ecclayout tegra_nand_oob_128 = {
> > + .eccbytes = 72,
> > + .eccpos = {
> > + 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,
> > + 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35,
> > + 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51,
> > + 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67,
> > + 68, 69, 70, 71, 72, 73, 74, 75
> > + },
> > + .oobfree = {
> > + { .offset = 76, .length = 52 }
> > + }
> > +};
> > +
> > +static struct nand_ecclayout tegra_nand_oob_224 = {
> > + .eccbytes = 144,
> > + .eccpos = {
> > + 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
> > + 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
> > + 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42,
> > + 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55,
> > + 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68,
> > + 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81,
> > + 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94,
> > + 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107,
> > + 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120,
> > + 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133,
> > + 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146,
> > + 147
> > + },
> > + .oobfree = {
> > + { .offset = 148, .length = 76 }
> > + }
> > +};
> > +
> > +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);
> > +
> > + if (!isr && !(dma & DMA_CTRL_IS_DONE))
> > + return IRQ_NONE;
> > +
> > + 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 void tegra_nand_command(struct mtd_info *mtd, unsigned int command,
> > + int column, int page_addr)
> > +{
> > + struct tegra_nand *nand = to_tegra_nand(mtd);
> > + u32 value;
> > +
> > + switch (command) {
> > + case NAND_CMD_READOOB:
> > + column += mtd->writesize;
> > + /* fall-through */
> > +
> > + case NAND_CMD_READ0:
> > + writel(NAND_CMD_READ0, nand->regs + CMD_1);
> > + writel(NAND_CMD_READSTART, nand->regs + CMD_2);
> > +
> > + value = (page_addr << 16) | (column & 0xffff);
> > + writel(value, nand->regs + ADDR_1);
> > +
> > + value = page_addr >> 16;
> > + writel(value, nand->regs + ADDR_2);
> > +
> > + value = CMD_CLE | CMD_ALE | CMD_ALE_SIZE(4) | CMD_SEC_CMD |
> > + CMD_RBSY_CHK | CMD_CE(nand->cur_chip) | CMD_GO;
> > + writel(value, nand->regs + CMD);
> > + break;
> > +
> > + case NAND_CMD_SEQIN:
> > + writel(NAND_CMD_SEQIN, nand->regs + CMD_1);
> > +
> > + value = (page_addr << 16) | (column & 0xffff);
> > + writel(value, nand->regs + ADDR_1);
> > +
> > + value = page_addr >> 16;
> > + writel(value, nand->regs + ADDR_2);
> > +
> > + value = CMD_CLE | CMD_ALE | CMD_ALE_SIZE(4) |
> > + CMD_CE(nand->cur_chip) | CMD_GO;
> > + writel(value, nand->regs + CMD);
> > + break;
> > +
> > + case NAND_CMD_PAGEPROG:
> > + writel(NAND_CMD_PAGEPROG, nand->regs + CMD_1);
> > +
> > + value = CMD_CLE | CMD_CE(nand->cur_chip) | CMD_GO;
> > + writel(value, nand->regs + CMD);
> > + break;
> > +
> > + case NAND_CMD_READID:
> > + writel(NAND_CMD_READID, nand->regs + CMD_1);
> > + writel(column & 0xff, nand->regs + ADDR_1);
> > +
> > + value = CMD_GO | CMD_CLE | CMD_ALE | CMD_CE(nand->cur_chip);
> > + writel(value, nand->regs + CMD);
> > + break;
> > +
> > + case NAND_CMD_ERASE1:
> > + writel(NAND_CMD_ERASE1, nand->regs + CMD_1);
> > + writel(NAND_CMD_ERASE2, nand->regs + CMD_2);
> > + writel(page_addr, nand->regs + ADDR_1);
> > +
> > + value = CMD_GO | CMD_CLE | CMD_ALE | CMD_ALE_SIZE(2) |
> > + CMD_SEC_CMD | CMD_RBSY_CHK | CMD_CE(nand->cur_chip);
> > + writel(value, nand->regs + CMD);
> > + break;
> > +
> > + case NAND_CMD_ERASE2:
> > + return;
> > +
> > + case NAND_CMD_STATUS:
> > + writel(NAND_CMD_STATUS, nand->regs + CMD_1);
> > +
> > + value = CMD_GO | CMD_CLE | CMD_CE(nand->cur_chip);
> > + writel(value, nand->regs + CMD);
> > + break;
> > +
> > + case NAND_CMD_PARAM:
> > + writel(NAND_CMD_PARAM, nand->regs + CMD_1);
> > + writel(column & 0xff, nand->regs + ADDR_1);
> > + value = CMD_GO | CMD_CLE | CMD_ALE | CMD_CE(nand->cur_chip);
> > + writel(value, nand->regs + CMD);
> > + break;
> > +
> > + case NAND_CMD_RESET:
> > + writel(NAND_CMD_RESET, nand->regs + CMD_1);
> > +
> > + value = CMD_GO | CMD_CLE | CMD_CE(nand->cur_chip);
> > + writel(value, nand->regs + CMD);
> > + break;
> > +
> > + default:
> > + dev_warn(nand->dev, "unsupported command: %x\n", command);
> > + return;
> > + }
> > +
> > + wait_for_completion(&nand->command_complete);
> > +}
> > +
> > +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 uint8_t tegra_nand_read_byte(struct mtd_info *mtd)
> > +{
> > + struct tegra_nand *nand = to_tegra_nand(mtd);
> > + u32 value;
> > +
> > + value = CMD_TRANS_SIZE(0) | CMD_CE(nand->cur_chip) |
> > + CMD_PIO | CMD_RX | CMD_A_VALID | CMD_GO;
> > +
> > + writel(value, nand->regs + CMD);
> > + wait_for_completion(&nand->command_complete);
> > +
> > + return readl(nand->regs + RESP) & 0xff;
> > +}
> > +
> > +static void tegra_nand_read_buf(struct mtd_info *mtd, uint8_t *buffer,
> > + int length)
> > +{
> > + struct tegra_nand *nand = to_tegra_nand(mtd);
> > + size_t i;
> > +
> > + for (i = 0; i < length; i += 4) {
> > + u32 value;
> > + size_t n = min_t(size_t, length - i, 4);
> > +
> > + value = CMD_GO | CMD_PIO | CMD_RX | CMD_A_VALID |
> > + CMD_CE(nand->cur_chip) | CMD_TRANS_SIZE(n - 1);
> > +
> > + writel(value, nand->regs + CMD);
> > + wait_for_completion(&nand->command_complete);
> > +
> > + value = readl(nand->regs + RESP);
> > + memcpy(buffer + i, &value, n);
> > + }
> > +}
> > +
> > +static void tegra_nand_write_buf(struct mtd_info *mtd, const uint8_t *buffer,
> > + int length)
> > +{
> > + struct tegra_nand *nand = to_tegra_nand(mtd);
> > + size_t i;
> > +
> > + for (i = 0; i < length; i += 4) {
> > + u32 value;
> > + size_t n = min_t(size_t, length - i, 4);
> > +
> > + memcpy(&value, buffer + i, n);
> > + writel(value, nand->regs + RESP);
> > +
> > + value = CMD_GO | CMD_PIO | CMD_TX | CMD_A_VALID |
> > + CMD_CE(nand->cur_chip) | CMD_TRANS_SIZE(n - 1);
> > +
> > + writel(value, nand->regs + CMD);
> > + wait_for_completion(&nand->command_complete);
> > + }
> > +}
> > +
> > +static int tegra_nand_read_page(struct mtd_info *mtd, struct nand_chip *chip,
> > + uint8_t *buf, int oob_required, int page)
> > +{
> > + struct tegra_nand *nand = to_tegra_nand(mtd);
> > + u32 value;
> > +
> > + value = readl(nand->regs + CFG);
> > + value |= CFG_HW_ECC | CFG_ERR_COR;
> > + writel(value, nand->regs + CFG);
> > +
> > + writel(mtd->writesize - 1, nand->regs + DMA_CFG_A);
> > + writel(nand->data_dma, nand->regs + DATA_PTR);
> > +
> > + if (oob_required) {
> > + writel(mtd->oobsize - 1, nand->regs + DMA_CFG_B);
> > + writel(nand->oob_dma, nand->regs + TAG_PTR);
> > + } else {
> > + writel(0, nand->regs + DMA_CFG_B);
> > + writel(0, nand->regs + TAG_PTR);
> > + }
> > +
> > + value = DMA_CTRL_GO | DMA_CTRL_IN | DMA_CTRL_PERF_EN |
> > + DMA_CTRL_REUSE | DMA_CTRL_IE_DONE | DMA_CTRL_IS_DONE |
> > + DMA_CTRL_BURST_8 | DMA_CTRL_EN_A;
> > +
> > + if (oob_required)
> > + value |= DMA_CTRL_EN_B;
> > +
> > + writel(value, nand->regs + DMA_CTRL);
> > +
> > + value = CMD_GO | CMD_RX | CMD_TRANS_SIZE(8) |
> > + CMD_A_VALID | CMD_CE(nand->cur_chip);
> > + if (oob_required)
> > + value |= CMD_B_VALID;
> > + writel(value, nand->regs + CMD);
> > +
> > + wait_for_completion(&nand->command_complete);
> > + wait_for_completion(&nand->dma_complete);
> > +
> > + if (oob_required)
> > + memcpy(chip->oob_poi, nand->oob_buf, mtd->oobsize);
> > + memcpy(buf, nand->data_buf, mtd->writesize);
> > +
> > + value = readl(nand->regs + CFG);
> > + value &= ~(CFG_HW_ECC | CFG_ERR_COR);
> > + writel(value, nand->regs + CFG);
> > +
> > + value = readl(nand->regs + DEC_STATUS);
> > +
> > + if (value & DEC_STATUS_A_ECC_FAIL) {
> > + /*
> > + * The ECC isn't smart enough to figure out if a page is
> > + * completely erased and flags an error in this case. So we
> > + * check the read data here to figure out if it's a legitimate
> > + * error or a false positive.
> > + */
> > + int i;
> > + u32 *data = (u32 *)buf;
> > + for (i = 0; i < mtd->writesize / 4; i++) {
> > + if (data[i] != 0xffffffff) {
> > + mtd->ecc_stats.failed++;
> > + return -EBADMSG;
> > + }
> > + }
>
> Hmm, what about OOB? It's possible to actually write 0xff to the entire
> page. This hunk means that such a data pattern would then be
> unprotected. You should probably check that *both* the main and OOB data
> are all 0xff; if there are non-0xff bytes, then that (probably, see the
> following) means someone intentionally wrote all 0xff to the page. [1]
>
This check is only executed if the ECC engine flagged a non-correctable
error. If someone wrote all 0xff to the page there will be a proper ECC
checksum calculated and we won't get into this path. So to get this
check to wrongly paper over a legitimate error someone would need to
write almost all 0xff with a few bits 0, which then flip to a 1
afterwards, which is highly unlikely as far as I understand flash
technology.
> Also, your check doesn't handle the case of finding bitflips in erased
> pages. So not only do you need to check for all 0xff, but you also need
> to tolerate a few flips. e.g., using hweight*() functions. There is
> plenty of discussion on this subject, as many people have tried to
> resolve this for their various drivers. But none have really done this
> in a thorough and correct way, so few have been merged. Thus, I'd really
> like to get something like this merged to nand_base.c, with a NAND_*
> flag or two to enable it. That would help drivers like yours to easily
> grab a good (albeit, likely slow) implementation.
>
Did those discussion lead somewhere? It seems they got stuck some time
ago. I'm all for using common infrastructure that does the right thing,
but I wouldn't like to base this driver on top of future work with no
clear roadmap.
> So, I'd like to see the first request (about OOB checks) solved, and if
> the larger bitflips-in-erased-pages issue isn't addressed, please
> include a FIXME comment, or something similar.
>
> > + return 0;
> > + }
> > +
> > + if (value & DEC_STATUS_ERR_COUNT_MASK) {
> > + value = (value & DEC_STATUS_ERR_COUNT_MASK) >>
> > + DEC_STATUS_ERR_COUNT_SHIFT;
>
> What does this ERR_COUNT represent? The total bitflips seen in this
> page? The max seen per ECC region? Or something else?
>
> > + mtd->ecc_stats.corrected += value;
>
> I ask because this ^^^ should be accounting the total bitflips for the
> page, if possible...
>
> > + return value;
>
> ...and this ^^^ should be returning the max bitflips seen in a single
> correction region (see the mtd_read() API). There is a subtle
> difference.
>
Urgh, yeah. The value is bitflips per page. I think there is another
register that should give max errors per ECC region, but I'm not sure it
works correctly. Will test that. Thanks for the hint.
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int tegra_nand_write_page(struct mtd_info *mtd, struct nand_chip *chip,
> > + const uint8_t *buf, int oob_required)
> > +{
> > + struct tegra_nand *nand = to_tegra_nand(mtd);
> > + unsigned long value;
> > +
> > + value = readl(nand->regs + CFG);
> > + value |= CFG_HW_ECC | CFG_ERR_COR;
> > + writel(value, nand->regs + CFG);
> > +
> > + memcpy(nand->data_buf, buf, mtd->writesize);
> > +
> > + writel(mtd->writesize - 1, nand->regs + DMA_CFG_A);
> > + writel(nand->data_dma, nand->regs + DATA_PTR);
> > +
> > + writel(0, nand->regs + DMA_CFG_B);
> > + writel(0, nand->regs + TAG_PTR);
> > +
> > + value = DMA_CTRL_GO | DMA_CTRL_OUT | DMA_CTRL_PERF_EN |
> > + DMA_CTRL_IE_DONE | DMA_CTRL_IS_DONE |
> > + DMA_CTRL_BURST_8 | DMA_CTRL_EN_A;
> > + writel(value, nand->regs + DMA_CTRL);
> > +
> > + value = CMD_GO | CMD_TX | CMD_A_VALID | CMD_TRANS_SIZE(8) |
> > + CMD_CE(nand->cur_chip);
> > + writel(value, nand->regs + CMD);
> > +
> > + wait_for_completion(&nand->command_complete);
> > + wait_for_completion(&nand->dma_complete);
> > +
> > + value = readl(nand->regs + CFG);
> > + value &= ~(CFG_HW_ECC | CFG_ERR_COR);
> > + writel(value, nand->regs + CFG);
> > +
> > + return 0;
> > +}
> > +
> > +static void tegra_nand_setup_timing(struct tegra_nand *nand, int mode)
> > +{
>
> This function could use some comments. The math can be easy to get
> wrong, especially without the annotation of units (e.g., picoseconds).
> Also, look out for rounding inaccuracies. DIV_ROUND_UP() is nice for
> getting conservative conversions at times.
>
The timing formulas are listed in the TRM and I don't think it makes
sense to repeat them here. Are you okay with a pointer to the relevant
section in the TRM?
> > + unsigned long rate = clk_get_rate(nand->clk) / 1000000;
> > + unsigned long period = 1000000 / rate;
> > + const struct nand_sdr_timings *timings;
> > + u32 val, reg = 0;
> > +
> > + timings = onfi_async_timing_mode_to_sdr_timings(mode);
> > +
> > + val = max3(timings->tAR_min, timings->tRR_min,
> > + timings->tRC_min) / period;
> > + if (val > 2)
> > + val -= 3;
> > + reg |= TIMING_TCR_TAR_TRR(val);
> > +
> > + val = max(max(timings->tCS_min, timings->tCH_min),
> > + max(timings->tALS_min, timings->tALH_min)) / period;
> > + if (val > 1)
> > + val -= 2;
> > + reg |= TIMING_TCS(val);
> > +
> > + val = (max(timings->tRP_min, timings->tREA_max) + 6000) / period;
> > + reg |= (TIMING_TRP(val) | TIMING_TRP_RESP(val));
> > +
> > + reg |= TIMING_TWB(timings->tWB_max / period);
> > + reg |= TIMING_TWHR(timings->tWHR_min / period);
> > + reg |= TIMING_TWH(timings->tWH_min / period);
> > + reg |= TIMING_TWP(timings->tWP_min / period);
> > + reg |= TIMING_TRH(timings->tRHW_min / period);
> > +
> > + writel(reg, nand->regs + TIMING_1);
> > +
> > + val = timings->tADL_min / period;
> > + if (val > 2)
> > + val -= 3;
> > + reg = TIMING_TADL(val);
> > +
> > + writel(reg, nand->regs + TIMING_2);
> > +}
> > +
> > +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);
> > +}
> > +
> > +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, buswidth, 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, "nvidia,wp-gpios",
> > + GPIOD_OUT_HIGH);
> > + if (IS_ERR(nand->wp_gpio))
> > + return PTR_ERR(nand->wp_gpio);
> > +
> > + buswidth = of_get_nand_bus_width(pdev->dev.of_node);
> > + if (buswidth < 0)
> > + return buswidth;
>
> You could set chip->dn, then nand_dt_init() might capture this for you.
>
Thanks, will do.
> > +
> > + 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);
> > +
> > + mtd = &nand->mtd;
> > + mtd->name = "tegra_nand";
> > + mtd->owner = THIS_MODULE;
> > + mtd->priv = &nand->chip;
> > +
> > + /* 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);
> > +
> > + value = 0;
> > + if (buswidth == 16)
> > + value |= CFG_BUS_WIDTH_16;
> > + writel(value, nand->regs + CFG);
> > +
> > + chip = &nand->chip;
> > + chip->options = NAND_NO_SUBPAGE_WRITE;
> > + chip->cmdfunc = tegra_nand_command;
> > + chip->select_chip = tegra_nand_select_chip;
> > + chip->read_byte = tegra_nand_read_byte;
> > + chip->read_buf = tegra_nand_read_buf;
> > + chip->write_buf = tegra_nand_write_buf;
> > +
> > + if (of_get_nand_on_flash_bbt(pdev->dev.of_node))
> > + chip->bbt_options = NAND_BBT_USE_FLASH | NAND_BBT_NO_OOB;
>
> Again, nand_dt_init() might help you. You might then augment it with:
>
> if (chip->bbt_options & NAND_BBT_USE_FLASH)
> chip->bbt_options |= NAND_BBT_NO_OOB;
>
> > +
> > + tegra_nand_setup_timing(nand, 0);
> > +
> > + err = nand_scan_ident(mtd, 1, NULL);
> > + if (err)
> > + return err;
> > +
> > + nand->data_buf = dmam_alloc_coherent(&pdev->dev, mtd->writesize,
> > + &nand->data_dma, GFP_KERNEL);
> > + if (!nand->data_buf)
> > + return -ENOMEM;
> > +
> > + nand->oob_buf = dmam_alloc_coherent(&pdev->dev, mtd->oobsize,
> > + &nand->oob_dma, GFP_KERNEL);
> > + if (!nand->oob_buf)
> > + return -ENOMEM;
> > +
> > + chip->ecc.mode = NAND_ECC_HW;
> > + chip->ecc.size = 512;
> > + chip->ecc.bytes = mtd->oobsize;
> > + chip->ecc.read_page = tegra_nand_read_page;
> > + chip->ecc.write_page = tegra_nand_write_page;
> > +
> > + value = readl(nand->regs + CFG);
> > + value |= CFG_PIPE_EN | CFG_SKIP_SPARE | CFG_SKIP_SPARE_SIZE_4;
> > +
> > + switch (mtd->oobsize) {
> > + case 16:
> > + chip->ecc.layout = &tegra_nand_oob_16;
> > + chip->ecc.strength = 1;
> > + value |= CFG_TAG_BYTE_SIZE(tegra_nand_oob_16.oobfree[0].length
> > + - 1);
> > + break;
> > + case 64:
> > + chip->ecc.layout = &tegra_nand_oob_64;
> > + chip->ecc.strength = 8;
> > + value |= CFG_ECC_SEL | CFG_TVAL_8 |
> > + CFG_TAG_BYTE_SIZE(tegra_nand_oob_64.oobfree[0].length
> > + - 1);
> > + break;
> > + case 128:
> > + chip->ecc.layout = &tegra_nand_oob_128;
> > + chip->ecc.strength = 8;
> > + value |= CFG_ECC_SEL | CFG_TVAL_8 |
> > + CFG_TAG_BYTE_SIZE(tegra_nand_oob_128.oobfree[0].length
> > + - 1);
> > + break;
> > + case 224:
> > + chip->ecc.layout = &tegra_nand_oob_224;
> > + chip->ecc.strength = 8;
> > + value |= CFG_ECC_SEL | CFG_TVAL_8 |
> > + CFG_TAG_BYTE_SIZE(tegra_nand_oob_224.oobfree[0].length
> > + - 1);
> > + break;
> > + default:
> > + dev_err(&pdev->dev, "unhandled OOB size %d\n", mtd->oobsize);
> > + return -ENODEV;
> > + }
> > +
> > + switch (mtd->writesize) {
> > + case 256:
> > + value |= CFG_PS_256;
> > + break;
> > + case 512:
> > + value |= CFG_PS_512;
> > + break;
> > + case 1024:
> > + value |= CFG_PS_1024;
> > + break;
> > + case 2048:
> > + value |= CFG_PS_2048;
> > + break;
> > + case 4096:
> > + value |= CFG_PS_4096;
> > + break;
> > + default:
> > + dev_err(&pdev->dev, "unhandled writesize %d\n", mtd->writesize);
> > + return -ENODEV;
> > + }
> > +
> > + writel(value, nand->regs + CFG);
> > +
> > + tegra_nand_setup_chiptiming(nand);
> > +
> > + err = nand_scan_tail(mtd);
> > + if (err)
> > + return err;
> > +
> > + mtd_device_parse_register(mtd, NULL,
> > + &(struct mtd_part_parser_data) {
> > + .of_node = pdev->dev.of_node,
> > + },
> > + NULL, 0);
>
> Check the return value for errors.
>
Will do,
Thanks,
Lucas
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