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Message-ID: <CAC=U0a2HHYDuEXLGOxjhYpDwBd-9G62tm7JXLK0BPqEkw1KWCA@mail.gmail.com>
Date: Wed, 22 Jan 2020 11:37:24 -0500
From: Kamal Dasu <kdasu.kdev@...il.com>
To: Miquel Raynal <miquel.raynal@...tlin.com>
Cc: MTD Maling List <linux-mtd@...ts.infradead.org>,
bcm-kernel-feedback-list <bcm-kernel-feedback-list@...adcom.com>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Brian Norris <computersforpeace@...il.com>,
Richard Weinberger <richard@....at>,
Vignesh Raghavendra <vigneshr@...com>,
Sumit Semwal <sumit.semwal@...aro.org>,
linux-media@...r.kernel.org, dri-devel@...ts.freedesktop.org,
linaro-mm-sig@...ts.linaro.org
Subject: Re: [PATCH V2 3/3] mtd: rawnand: brcmnand: Add support for flash-edu
for dma transfers
On Wed, Jan 22, 2020 at 3:50 AM Miquel Raynal <miquel.raynal@...tlin.com> wrote:
>
> Hi Kamal,
>
> I'm fine with the patch, nitpicking below :)
>
> Kamal Dasu <kdasu.kdev@...il.com> wrote on Tue, 21 Jan 2020 15:00:08
> -0500:
>
> > Legacy mips soc platforms that have controller v5.0 and 6.0 use
> > flash-edu block for dma transfers. This change adds support for
> > nand dma transfers using the EDU block.
> >
> > Signed-off-by: Kamal Dasu <kdasu.kdev@...il.com>
> > ---
> > drivers/mtd/nand/raw/brcmnand/brcmnand.c | 296 ++++++++++++++++++++++-
> > 1 file changed, 290 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/mtd/nand/raw/brcmnand/brcmnand.c b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
> > index 1a66b1cd51c0..61347607f1da 100644
> > --- a/drivers/mtd/nand/raw/brcmnand/brcmnand.c
> > +++ b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
> > @@ -102,6 +102,45 @@ struct brcm_nand_dma_desc {
> > #define NAND_CTRL_RDY (INTFC_CTLR_READY | INTFC_FLASH_READY)
> > #define NAND_POLL_STATUS_TIMEOUT_MS 100
> >
> > +#define EDU_CMD_WRITE 0x00
> > +#define EDU_CMD_READ 0x01
> > +#define EDU_STATUS_ACTIVE BIT(0)
> > +#define EDU_ERR_STATUS_ERRACK BIT(0)
> > +#define EDU_DONE_MASK GENMASK(1, 0)
> > +
> > +#define EDU_CONFIG_MODE_NAND BIT(0)
> > +#define EDU_CONFIG_SWAP_BYTE BIT(1)
> > +#ifdef CONFIG_CPU_BIG_ENDIAN
> > +#define EDU_CONFIG_SWAP_CFG EDU_CONFIG_SWAP_BYTE
> > +#else
> > +#define EDU_CONFIG_SWAP_CFG 0
> > +#endif
> > +
> > +/* edu registers */
> > +enum edu_reg {
> > + EDU_CONFIG = 0,
> > + EDU_DRAM_ADDR,
> > + EDU_EXT_ADDR,
> > + EDU_LENGTH,
> > + EDU_CMD,
> > + EDU_STOP,
> > + EDU_STATUS,
> > + EDU_DONE,
> > + EDU_ERR_STATUS,
> > +};
> > +
> > +static const u16 edu_regs[] = {
> > + [EDU_CONFIG] = 0x00,
> > + [EDU_DRAM_ADDR] = 0x04,
> > + [EDU_EXT_ADDR] = 0x08,
> > + [EDU_LENGTH] = 0x0c,
> > + [EDU_CMD] = 0x10,
> > + [EDU_STOP] = 0x14,
> > + [EDU_STATUS] = 0x18,
> > + [EDU_DONE] = 0x1c,
> > + [EDU_ERR_STATUS] = 0x20,
> > +};
>
> Why not defining the offsets in the enum directly?
>
EDU is separate block and following the convention used fr the rest of
the driver. Would prefer to keep it this way.
> > +
> > /* flash_dma registers */
> > enum flash_dma_reg {
> > FLASH_DMA_REVISION = 0,
> > @@ -167,6 +206,8 @@ enum {
> > BRCMNAND_HAS_WP = BIT(3),
> > };
> >
> > +struct brcmnand_host;
> > +
> > struct brcmnand_controller {
> > struct device *dev;
> > struct nand_controller controller;
> > @@ -185,17 +226,32 @@ struct brcmnand_controller {
> >
> > int cmd_pending;
> > bool dma_pending;
> > + bool edu_pending;
> > struct completion done;
> > struct completion dma_done;
> > + struct completion edu_done;
> >
> > /* List of NAND hosts (one for each chip-select) */
> > struct list_head host_list;
> >
> > + /* EDU info, per-transaction */
> > + const u16 *edu_offsets;
> > + void __iomem *edu_base;
> > + unsigned int edu_irq;
> > + int edu_count;
> > + u64 edu_dram_addr;
> > + u32 edu_ext_addr;
> > + u32 edu_cmd;
> > + u32 edu_config;
> > +
> > /* flash_dma reg */
> > const u16 *flash_dma_offsets;
> > struct brcm_nand_dma_desc *dma_desc;
> > dma_addr_t dma_pa;
> >
> > + int (*dma_trans)(struct brcmnand_host *host, u64 addr, u32 *buf,
> > + u32 len, u8 dma_cmd);
> > +
> > /* in-memory cache of the FLASH_CACHE, used only for some commands */
> > u8 flash_cache[FC_BYTES];
> >
> > @@ -216,6 +272,7 @@ struct brcmnand_controller {
> > u32 nand_cs_nand_xor;
> > u32 corr_stat_threshold;
> > u32 flash_dma_mode;
> > + u32 flash_edu_mode;
> > bool pio_poll_mode;
> > };
> >
> > @@ -657,6 +714,22 @@ static inline void brcmnand_write_fc(struct brcmnand_controller *ctrl,
> > __raw_writel(val, ctrl->nand_fc + word * 4);
> > }
> >
> > +static inline void edu_writel(struct brcmnand_controller *ctrl,
> > + enum edu_reg reg, u32 val)
> > +{
> > + u16 offs = ctrl->edu_offsets[reg];
> > +
> > + brcmnand_writel(val, ctrl->edu_base + offs);
> > +}
> > +
> > +static inline u32 edu_readl(struct brcmnand_controller *ctrl,
> > + enum edu_reg reg)
> > +{
> > + u16 offs = ctrl->edu_offsets[reg];
> > +
> > + return brcmnand_readl(ctrl->edu_base + offs);
> > +}
> > +
> > static void brcmnand_clear_ecc_addr(struct brcmnand_controller *ctrl)
> > {
> >
> > @@ -926,6 +999,16 @@ static inline bool has_flash_dma(struct brcmnand_controller *ctrl)
> > return ctrl->flash_dma_base;
> > }
> >
> > +static inline bool has_edu(struct brcmnand_controller *ctrl)
> > +{
> > + return ctrl->edu_base;
> > +}
> > +
> > +static inline bool use_dma(struct brcmnand_controller *ctrl)
> > +{
> > + return has_flash_dma(ctrl) || has_edu(ctrl);
> > +}
> > +
> > static inline void disable_ctrl_irqs(struct brcmnand_controller *ctrl)
> > {
> > if (ctrl->pio_poll_mode)
> > @@ -1299,6 +1382,52 @@ static int write_oob_to_regs(struct brcmnand_controller *ctrl, int i,
> > return tbytes;
> > }
> >
> > +static void brcmnand_edu_init(struct brcmnand_controller *ctrl)
> > +{
> > + /* initialize edu */
> > + edu_writel(ctrl, EDU_ERR_STATUS, 0);
> > + edu_readl(ctrl, EDU_ERR_STATUS);
> > + edu_writel(ctrl, EDU_DONE, 0);
> > + edu_writel(ctrl, EDU_DONE, 0);
> > + edu_writel(ctrl, EDU_DONE, 0);
> > + edu_writel(ctrl, EDU_DONE, 0);
> > + edu_readl(ctrl, EDU_DONE);
> > +}
> > +
> > +/* edu irq */
> > +static irqreturn_t brcmnand_edu_irq(int irq, void *data)
> > +{
> > + struct brcmnand_controller *ctrl = data;
> > +
> > + if (ctrl->edu_count) {
> > + ctrl->edu_count--;
> > + while (!(edu_readl(ctrl, EDU_DONE) & EDU_DONE_MASK))
> > + udelay(1);
> > + edu_writel(ctrl, EDU_DONE, 0);
> > + edu_readl(ctrl, EDU_DONE);
> > + }
> > +
> > + if (ctrl->edu_count) {
> > + ctrl->edu_dram_addr += FC_BYTES;
> > + ctrl->edu_ext_addr += FC_BYTES;
> > +
> > + edu_writel(ctrl, EDU_DRAM_ADDR, (u32)ctrl->edu_dram_addr);
> > + edu_readl(ctrl, EDU_DRAM_ADDR);
> > + edu_writel(ctrl, EDU_EXT_ADDR, ctrl->edu_ext_addr);
> > + edu_readl(ctrl, EDU_EXT_ADDR);
> > +
> > + mb(); /* flush previous writes */
> > + edu_writel(ctrl, EDU_CMD, ctrl->edu_cmd);
> > + edu_readl(ctrl, EDU_CMD);
> > +
> > + return IRQ_HANDLED;
> > + }
> > +
> > + complete(&ctrl->edu_done);
> > +
> > + return IRQ_HANDLED;
> > +}
> > +
> > static irqreturn_t brcmnand_ctlrdy_irq(int irq, void *data)
> > {
> > struct brcmnand_controller *ctrl = data;
> > @@ -1307,6 +1436,16 @@ static irqreturn_t brcmnand_ctlrdy_irq(int irq, void *data)
> > if (ctrl->dma_pending)
> > return IRQ_HANDLED;
> >
> > + /* check if you need to piggy back on the ctrlrdy irq */
> > + if (ctrl->edu_pending) {
> > + if (irq == ctrl->irq && ((int)ctrl->edu_irq >= 0))
> > + /* Discard interrupts while using dedicated edu irq */
> > + return IRQ_HANDLED;
> > +
> > + /* no registered edu irq, call handler */
> > + return brcmnand_edu_irq(irq, data);
> > + }
> > +
> > complete(&ctrl->done);
> > return IRQ_HANDLED;
> > }
> > @@ -1644,6 +1783,83 @@ static void brcmnand_write_buf(struct nand_chip *chip, const uint8_t *buf,
> > }
> > }
> >
> > +/**
> > + * Kick EDU engine
> > + */
> > +static int brcmnand_edu_trans(struct brcmnand_host *host, u64 addr, u32 *buf,
> > + u32 len, u8 cmd)
> > +{
> > + struct brcmnand_controller *ctrl = host->ctrl;
> > + unsigned long timeo = msecs_to_jiffies(200);
> > + int ret = 0;
> > + int dir = (cmd == CMD_PAGE_READ ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
> > + u8 edu_cmd = (cmd == CMD_PAGE_READ ? EDU_CMD_READ : EDU_CMD_WRITE);
> > + unsigned int trans = len >> FC_SHIFT;
> > + dma_addr_t pa;
> > +
> > + pa = dma_map_single(ctrl->dev, buf, len, dir);
> > + if (dma_mapping_error(ctrl->dev, pa)) {
> > + dev_err(ctrl->dev, "unable to map buffer for EDU DMA\n");
> > + return -ENOMEM;
> > + }
> > +
> > + ctrl->edu_pending = true;
> > + mb(); /* flush previous writes */
>
> I'd prefer to have the barriers right after the IO access. I don't
> think it changes anything but that would ease understand what writes
> are you concerned about. Also, maybe you can use non _relaxed accessors
> as you usually writel/readl in raw, I don't think you actually need a
> barrier in this case.
>
Agree will remove the barrier.
> > +
> > + ctrl->edu_dram_addr = pa;
> > + ctrl->edu_ext_addr = addr;
> > + ctrl->edu_cmd = edu_cmd;
> > + ctrl->edu_count = trans;
> > +
> > + edu_writel(ctrl, EDU_DRAM_ADDR, (u32)ctrl->edu_dram_addr);
> > + edu_readl(ctrl, EDU_DRAM_ADDR);
> > + edu_writel(ctrl, EDU_EXT_ADDR, ctrl->edu_ext_addr);
> > + edu_readl(ctrl, EDU_EXT_ADDR);
> > + edu_writel(ctrl, EDU_LENGTH, FC_BYTES);
> > + edu_readl(ctrl, EDU_LENGTH);
> > +
> > + /* Start edu engine */
> > + mb(); /* flush previous writes */
> > + edu_writel(ctrl, EDU_CMD, ctrl->edu_cmd);
> > + edu_readl(ctrl, EDU_CMD);
> > +
> > + if (wait_for_completion_timeout(&ctrl->edu_done, timeo) <= 0) {
> > + dev_err(ctrl->dev,
> > + "timeout waiting for EDU; status %#x, error status %#x\n",
> > + edu_readl(ctrl, EDU_STATUS),
> > + edu_readl(ctrl, EDU_ERR_STATUS));
> > + }
> > +
> > + dma_unmap_single(ctrl->dev, pa, len, dir);
> > +
> > + /* for program page check NAND status */
> > + if (((brcmnand_read_reg(ctrl, BRCMNAND_INTFC_STATUS) &
> > + INTFC_FLASH_STATUS) & NAND_STATUS_FAIL) &&
> > + edu_cmd == EDU_CMD_WRITE) {
> > + dev_info(ctrl->dev, "program failed at %llx\n",
> > + (unsigned long long)addr);
> > + ret = -EIO;
> > + }
> > +
> > + /* Make sure the EDU status is clean */
> > + if (edu_readl(ctrl, EDU_STATUS) & EDU_STATUS_ACTIVE)
> > + dev_warn(ctrl->dev, "EDU still active: %#x\n",
> > + edu_readl(ctrl, EDU_STATUS));
> > +
> > + if (unlikely(edu_readl(ctrl, EDU_ERR_STATUS) & EDU_ERR_STATUS_ERRACK)) {
> > + dev_warn(ctrl->dev, "EDU RBUS error at addr %llx\n",
> > + (unsigned long long)addr);
> > + ret = -EIO;
> > + }
> > +
> > + ctrl->edu_pending = false;
> > + brcmnand_edu_init(ctrl);
> > + edu_writel(ctrl, EDU_STOP, 0); /* force stop */
> > + edu_readl(ctrl, EDU_STOP);
> > +
> > + return ret;
> > +}
> > +
> > /**
> > * Construct a FLASH_DMA descriptor as part of a linked list. You must know the
> > * following ahead of time:
> > @@ -1850,9 +2066,11 @@ static int brcmnand_read(struct mtd_info *mtd, struct nand_chip *chip,
> > try_dmaread:
> > brcmnand_clear_ecc_addr(ctrl);
> >
> > - if (has_flash_dma(ctrl) && !oob && flash_dma_buf_ok(buf)) {
> > - err = brcmnand_dma_trans(host, addr, buf, trans * FC_BYTES,
> > - CMD_PAGE_READ);
> > + if (ctrl->dma_trans && !oob && flash_dma_buf_ok(buf)) {
> > + err = ctrl->dma_trans(host, addr, buf,
> > + trans * FC_BYTES,
> > + CMD_PAGE_READ);
> > +
> > if (err) {
> > if (mtd_is_bitflip_or_eccerr(err))
> > err_addr = addr;
> > @@ -1988,10 +2206,12 @@ static int brcmnand_write(struct mtd_info *mtd, struct nand_chip *chip,
> > for (i = 0; i < ctrl->max_oob; i += 4)
> > oob_reg_write(ctrl, i, 0xffffffff);
> >
> > - if (has_flash_dma(ctrl) && !oob && flash_dma_buf_ok(buf)) {
> > - if (brcmnand_dma_trans(host, addr, (u32 *)buf,
> > - mtd->writesize, CMD_PROGRAM_PAGE))
> > + if (use_dma(ctrl) && !oob && flash_dma_buf_ok(buf)) {
> > + if (ctrl->dma_trans(host, addr, (u32 *)buf, mtd->writesize,
> > + CMD_PROGRAM_PAGE))
> > +
> > ret = -EIO;
> > +
> > goto out;
> > }
> >
> > @@ -2494,6 +2714,8 @@ static int brcmnand_suspend(struct device *dev)
> >
> > if (has_flash_dma(ctrl))
> > ctrl->flash_dma_mode = flash_dma_readl(ctrl, FLASH_DMA_MODE);
> > + else if (has_edu(ctrl))
> > + ctrl->edu_config = edu_readl(ctrl, EDU_CONFIG);
> >
> > return 0;
> > }
> > @@ -2508,6 +2730,14 @@ static int brcmnand_resume(struct device *dev)
> > flash_dma_writel(ctrl, FLASH_DMA_ERROR_STATUS, 0);
> > }
> >
> > + if (has_edu(ctrl))
> > + ctrl->edu_config = edu_readl(ctrl, EDU_CONFIG);
> > + else {
> > + edu_writel(ctrl, EDU_CONFIG, ctrl->edu_config);
> > + edu_readl(ctrl, EDU_CONFIG);
> > + brcmnand_edu_init(ctrl);
> > + }
> > +
> > brcmnand_write_reg(ctrl, BRCMNAND_CS_SELECT, ctrl->nand_cs_nand_select);
> > brcmnand_write_reg(ctrl, BRCMNAND_CS_XOR, ctrl->nand_cs_nand_xor);
> > brcmnand_write_reg(ctrl, BRCMNAND_CORR_THRESHOLD,
> > @@ -2553,6 +2783,52 @@ MODULE_DEVICE_TABLE(of, brcmnand_of_match);
> > /***********************************************************************
> > * Platform driver setup (per controller)
> > ***********************************************************************/
> > +static int brcmnand_edu_setup(struct platform_device *pdev)
> > +{
> > + struct device *dev = &pdev->dev;
> > + struct brcmnand_controller *ctrl = dev_get_drvdata(&pdev->dev);
> > + struct resource *res;
> > + int ret;
> > +
> > + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "flash-edu");
> > + if (res) {
> > + ctrl->edu_base = devm_ioremap_resource(dev, res);
> > + if (IS_ERR(ctrl->edu_base))
> > + return PTR_ERR(ctrl->edu_base);
> > +
> > + ctrl->edu_offsets = edu_regs;
> > +
> > + edu_writel(ctrl, EDU_CONFIG, EDU_CONFIG_MODE_NAND |
> > + EDU_CONFIG_SWAP_CFG);
> > + edu_readl(ctrl, EDU_CONFIG);
> > +
> > + /* initialize edu */
> > + brcmnand_edu_init(ctrl);
> > +
> > + ctrl->edu_irq = platform_get_irq_optional(pdev, 1);
> > + if ((int)ctrl->edu_irq < 0) {
>
> Why not declaring it as an int directly? I think it's preferred.
>
Ok will make this change
> > + dev_warn(dev,
> > + "FLASH EDU enabled, using ctlrdy irq\n");
> > + } else {
> > + ret = devm_request_irq(dev, ctrl->edu_irq,
> > + brcmnand_edu_irq, 0,
> > + "brcmnand-edu", ctrl);
> > + if (ret < 0) {
> > + dev_err(ctrl->dev, "can't allocate IRQ %d: error %d\n",
> > + ctrl->edu_irq, ret);
> > + return ret;
> > + }
> > +
> > + dev_info(dev, "FLASH EDU enabled using irq %u\n",
> > + ctrl->edu_irq);
> > + }
> > +
> > + /* set the appropriate edu transfer function to call */
> > + ctrl->dma_trans = brcmnand_edu_trans;
> > + }
> > +
> > + return 0;
> > +}
> >
> > int brcmnand_probe(struct platform_device *pdev, struct brcmnand_soc *soc)
> > {
> > @@ -2578,6 +2854,7 @@ int brcmnand_probe(struct platform_device *pdev, struct brcmnand_soc *soc)
> >
> > init_completion(&ctrl->done);
> > init_completion(&ctrl->dma_done);
> > + init_completion(&ctrl->edu_done);
> > nand_controller_init(&ctrl->controller);
> > ctrl->controller.ops = &brcmnand_controller_ops;
> > INIT_LIST_HEAD(&ctrl->host_list);
> > @@ -2623,6 +2900,7 @@ int brcmnand_probe(struct platform_device *pdev, struct brcmnand_soc *soc)
> > ctrl->reg_offsets[BRCMNAND_FC_BASE];
> > }
> >
> > + ctrl->dma_trans = NULL;
> > /* FLASH_DMA */
> > res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "flash-dma");
> > if (res) {
> > @@ -2665,6 +2943,12 @@ int brcmnand_probe(struct platform_device *pdev, struct brcmnand_soc *soc)
> > }
> >
> > dev_info(dev, "enabling FLASH_DMA\n");
> > + /* set the appropriate flash dma transfer function to call */
> > + ctrl->dma_trans = brcmnand_dma_trans;
> > + } else {
> > + ret = brcmnand_edu_setup(pdev);
> > + if (ret < 0)
> > + goto err;
>
> Nitpicking: you could drop the initialization of dma_trans to NULL and
> assign ctrl->dma_trans in both cases of this if/else block (by moving
> it out of the brcmnand_edu_setup()). I think it enhances readability.
>
Will make this change as well.
> > }
> >
> > /* Disable automatic device ID config, direct addressing */
>
>
> Thanks,
> Miquèl
Will send a V3 patch with the changes.
Thanks
Kamal
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