Messages in this thread | | | Date | Tue, 3 May 2022 15:54:19 +0200 | Subject | Re: [PATCH] mtd: nand: ecc-mtk: add external ecc engine support | From | AngeloGioacchino Del Regno <> |
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Il 30/04/22 18:40, Chuanhong Guo ha scritto: > This adds support for using ecc-mtk as an external ECC engine. > > The implemented OOB layout follows the convention to put all ECC data > at the end of OOB. As a result, the data layout is incompatible with > MTK NFI piplined ECC mode. > > Signed-off-by: Chuanhong Guo <gch981213@gmail.com> > --- > drivers/mtd/nand/ecc-mtk.c | 335 ++++++++++++++++++++++++++++++++++++- > 1 file changed, 331 insertions(+), 4 deletions(-) > > diff --git a/drivers/mtd/nand/ecc-mtk.c b/drivers/mtd/nand/ecc-mtk.c > index 9f9b201fe706..998276ada671 100644 > --- a/drivers/mtd/nand/ecc-mtk.c > +++ b/drivers/mtd/nand/ecc-mtk.c > @@ -15,6 +15,7 @@ > #include <linux/of.h> > #include <linux/of_platform.h> > #include <linux/mutex.h> > +#include <linux/mtd/nand.h> > #include <linux/mtd/nand-ecc-mtk.h> > > #define ECC_IDLE_MASK BIT(0) > @@ -26,12 +27,14 @@ > #define ECC_ENCCON (0x00) > #define ECC_ENCCNFG (0x04) > #define ECC_MS_SHIFT (16) > +#define ECC_MAX_MS (8191) > #define ECC_ENCDIADDR (0x08) > #define ECC_ENCIDLE (0x0C) > #define ECC_DECCON (0x100) > #define ECC_DECCNFG (0x104) > #define DEC_EMPTY_EN BIT(31) > #define DEC_CNFG_CORRECT (0x3 << 12) > +#define ECC_DECDIADDR (0x108) > #define ECC_DECIDLE (0x10C) > #define ECC_DECENUM0 (0x114) > > @@ -59,11 +62,23 @@ struct mtk_ecc { > > struct completion done; > struct mutex lock; > + struct nand_ecc_engine ecc_eng; > u32 sectors; > + u32 refcnt;
Please always use signed values for refcounts.
> > u8 *eccdata; > }; > > +struct mtk_ecc_host_ctx { > + struct mtk_ecc_config cfg; > + struct nand_ecc_req_tweak_ctx req_ctx; > + u8 *buf; > + dma_addr_t buf_dma; > + u32 free_len; > + u32 parity_len; > + u32 steps; > +}; > + > /* ecc strength that each IP supports */ > static const u8 ecc_strength_mt2701[] = { > 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 28, 32, 36, > @@ -75,6 +90,8 @@ static const u8 ecc_strength_mt2712[] = { > 40, 44, 48, 52, 56, 60, 68, 72, 80 > }; > > +static const u8 ecc_strength_mt7621[] = { 4 }; Please remove this one.
> + > static const u8 ecc_strength_mt7622[] = { > 4, 6, 8, 10, 12 > }; > @@ -115,6 +132,13 @@ static int mt7622_ecc_regs[] = { > [ECC_DECIRQ_STA] = 0x144, > }; >
..snip..
> @@ -239,8 +268,14 @@ EXPORT_SYMBOL(mtk_ecc_get_stats); > > void mtk_ecc_release(struct mtk_ecc *ecc) > { > - clk_disable_unprepare(ecc->clk); > - put_device(ecc->dev); > + mutex_lock(&ecc->lock); > + > + ecc->refcnt--; > + if (!ecc->refcnt) {
For the sake of readability, be explicit here.
if (ecc->refcnt == 0)
...also, for safety (since we're talking about data here) it may be worth to add a
WARN((ecc->refcnt < 0), "sensible warning message here");
> + clk_disable_unprepare(ecc->clk); > + put_device(ecc->dev); > + } > + mutex_unlock(&ecc->lock); > } > EXPORT_SYMBOL(mtk_ecc_release); >
> + > +static int mtk_ecc_host_init_ctx(struct nand_device *nand) > +{ > + struct mtk_ecc *ecc = nand_to_mtk_ecc(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); > + const u8 *ecc_strength = ecc->caps->ecc_strength;
struct mtk_ecc_host_ctx *ctx; belongs here.
> + int step_size = 0, strength = 0; > + int ret = 0; > + struct mtk_ecc_host_ctx *ctx;
...not here.
> + int steps, parity_len; > + int i; > + u32 parity_bits; > +
..snip..
> + > + dev_info(ecc->dev, "OOB: free: %u bytes, ECC: %u bytes", ctx->free_len, > + ctx->parity_len * ctx->steps); > + dev_info(ecc->dev, "ECC strength: %d bits per %d bytes\n", strength, > + step_size);
I'm not sure that this should really be a dev_info(), or at least not both.. as I don't think that this is that much informative anyway.
I'd go for dev_dbg() instead.
> + return 0; > +free_buf: > + dma_free_coherent(ecc->dev, step_size + parity_len, ctx->buf, > + ctx->buf_dma); > +free_ctx: > + kfree(ctx); > + return ret; > +} > +
..snip..
> +static int mtk_ecc_host_prepare_io_req(struct nand_device *nand, > + struct nand_page_io_req *req) > +{ > + struct mtk_ecc *ecc = nand_to_mtk_ecc(nand); > + struct mtd_info *mtd = nanddev_to_mtd(nand); > + struct mtk_ecc_host_ctx *ctx = nand_to_ecc_ctx(nand); > + int ret, step; > + > + if (req->mode == MTD_OPS_RAW) > + return 0; > + > + nand_ecc_tweak_req(&ctx->req_ctx, req); > + > + if (req->type == NAND_PAGE_READ) > + return 0; > + > + ctx->cfg.op = ECC_ENCODE; > + > + for (step = 0; step < ctx->steps; step++) { > + ctx->cfg.addr = dma_map_single( > + ecc->dev, (u8 *)req->databuf.out + step * ctx->cfg.len, > + ctx->cfg.len, DMA_TO_DEVICE); > + ret = dma_mapping_error(ecc->dev, ctx->cfg.addr); > + if (ret) { > + dev_err(ecc->dev, "DMA mapping failed.\n"); > + return ret; > + } > + ret = mtk_ecc_enable(ecc, &ctx->cfg); > + if (ret) { > + dma_unmap_single(ecc->dev, ctx->cfg.addr, ctx->cfg.len, > + DMA_TO_DEVICE); > + return ret; > + } > + > + ret = mtk_ecc_wait_done(ecc, ECC_ENCODE); > + if (ret) { > + mtk_ecc_disable(ecc); > + dma_unmap_single(ecc->dev, ctx->cfg.addr, ctx->cfg.len, > + DMA_TO_DEVICE); > + return ret; > + } > + > + mtk_ecc_wait_idle(ecc, ECC_ENCODE); > + dma_unmap_single(ecc->dev, ctx->cfg.addr, ctx->cfg.len, > + DMA_TO_DEVICE); > + __ioread32_copy(ecc->eccdata, > + ecc->regs + ecc->caps->ecc_regs[ECC_ENCPAR00], > + round_up(ctx->parity_len, 4)); > + mtd_ooblayout_set_eccbytes(mtd, ecc->eccdata, > + (void *)req->oobbuf.out, > + ctx->parity_len * step, > + ctx->parity_len); > + mtk_ecc_disable(ecc); > + } > + > + return ret;
You have addressed all of the error conditions, so return 0 here.
> +} > + > +static int mtk_ecc_host_finish_io_req(struct nand_device *nand, > + struct nand_page_io_req *req) > +{ > + struct mtk_ecc *ecc = nand_to_mtk_ecc(nand); > + struct mtd_info *mtd = nanddev_to_mtd(nand); > + struct mtk_ecc_host_ctx *ctx = nand_to_ecc_ctx(nand); > + u32 bitflips = 0, failed = 0; > + int ret, step, i;
> + u32 err;
It would be more appropriate to call this variable "val" or "regval".
Also, please reorder the variables, you can do it by name...
struct mtk_ecc_host_ctx *ctx = nand_to_ecc_ctx(nand); struct mtk_ecc *ecc = nand_to_mtk_ecc(nand); struct mtd_info *mtd = nanddev_to_mtd(nand); u32 bitflips = 0, failed = 0, regval; int ret, step, i;
Please also do the same for the other instances of that.
> + > + /* Nothing to do for a raw operation */ > + if (req->mode == MTD_OPS_RAW) > + return 0; > + > + /* This engine does not provide BBM/free OOB bytes protection */ > + if (!req->datalen) > + return 0; > + > + /* No more preparation for page write */ > + if (req->type == NAND_PAGE_WRITE) { > + nand_ecc_restore_req(&ctx->req_ctx, req); > + return 0; > + } > + > + ctx->cfg.op = ECC_DECODE; > + ctx->cfg.addr = ctx->buf_dma; > + > + for (step = 0; step < ctx->steps; step++) { > + memcpy(ctx->buf, req->databuf.in + step * ctx->cfg.len, > + ctx->cfg.len); > + mtd_ooblayout_get_eccbytes(mtd, ctx->buf + ctx->cfg.len, > + req->oobbuf.in, > + ctx->parity_len * step, > + ctx->parity_len); > + > + ret = mtk_ecc_enable(ecc, &ctx->cfg); > + if (ret) > + break; > + > + ret = mtk_ecc_wait_done(ecc, ECC_DECODE); > + if (ret)
I think that you forgot to revert the enablement here; translation: you probably forgot to call mtk_ecc_disable(ecc). Or is there any particular and valid reason to not do that here?
If there is, you should add a comment explaining why.
> + break; > + > + mtk_ecc_wait_idle(ecc, ECC_DECODE); > + > + memcpy(req->databuf.in + step * ctx->cfg.len, ctx->buf, > + ctx->cfg.len);
You can avoid breaking this line, as this results in 87 cols, which is fine. Same for the other memcpy before that one, and all other instances.
> + mtd_ooblayout_set_eccbytes(mtd, ctx->buf + ctx->cfg.len, > + req->oobbuf.in, > + ctx->parity_len * step, > + ctx->parity_len); > + err = readl(ecc->regs + ECC_DECENUM0); > + err &= ecc->caps->err_mask; > + if (err == ecc->caps->err_mask) { > + // skip empty page
C-style comments please. /* */
Regards, Angelo
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