Messages in this thread | | | Date | Mon, 13 Mar 2023 12:18:08 +0100 | From | Miquel Raynal <> | Subject | Re: [RFC PATCH v1] mtd: rawnand: meson: invalidate cache on polling ECC bit |
| |
Hi Arseniy,
avkrasnov@sberdevices.ru wrote on Mon, 13 Mar 2023 10:36:11 +0300:
> Hello, > > we reproduced this problem on one of our boards. It triggers very rare > when 'usleep_range()' is present, but when sleeping is removed - it fires > always. I suppose problem is with caching, as 'info_buf' memory is mapped by > 'dma_map_single()'.
The fix looks really legitimate, indeed I get that the usleep_range() might make it work most of the time but not always. Having this bit in a DMA buf area is a bit strange. Well, the fix LGTM anyway.
> > Thanks, Arseniy > > On 13.03.2023 10:32, Arseniy Krasnov wrote: > > 'info_buf' memory is cached and driver polls ECC bit in it. This bit > > is set by the NAND controller. If 'usleep_range()' returns before device > > sets this bit, 'info_buf' will be cached and driver won't see update of > > this bit and will loop forever. > > > > Fixes: 8fae856c5350 ("mtd: rawnand: meson: add support for Amlogic NAND flash controller") > > Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru> > > --- > > drivers/mtd/nand/raw/meson_nand.c | 8 +++++++- > > 1 file changed, 7 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/mtd/nand/raw/meson_nand.c b/drivers/mtd/nand/raw/meson_nand.c > > index 5ee01231ac4c..2c05c08a0eaf 100644 > > --- a/drivers/mtd/nand/raw/meson_nand.c > > +++ b/drivers/mtd/nand/raw/meson_nand.c > > @@ -176,6 +176,7 @@ struct meson_nfc { > > > > dma_addr_t daddr; > > dma_addr_t iaddr; > > + u32 info_bytes; > > > > unsigned long assigned_cs; > > }; > > @@ -503,6 +504,7 @@ static int meson_nfc_dma_buffer_setup(struct nand_chip *nand, void *databuf, > > nfc->daddr, datalen, dir); > > return ret; > > } > > + nfc->info_bytes = infolen; > > cmd = GENCMDIADDRL(NFC_CMD_AIL, nfc->iaddr); > > writel(cmd, nfc->reg_base + NFC_REG_CMD); > > > > @@ -520,8 +522,10 @@ static void meson_nfc_dma_buffer_release(struct nand_chip *nand, > > struct meson_nfc *nfc = nand_get_controller_data(nand); > > > > dma_unmap_single(nfc->dev, nfc->daddr, datalen, dir); > > - if (infolen) > > + if (infolen) { > > dma_unmap_single(nfc->dev, nfc->iaddr, infolen, dir); > > + nfc->info_bytes = 0; > > + } > > } > > > > static int meson_nfc_read_buf(struct nand_chip *nand, u8 *buf, int len) > > @@ -710,6 +714,8 @@ static void meson_nfc_check_ecc_pages_valid(struct meson_nfc *nfc, > > usleep_range(10, 15); > > /* info is updated by nfc dma engine*/ > > smp_rmb(); > > + dma_sync_single_for_cpu(nfc->dev, nfc->iaddr, nfc->info_bytes, > > + DMA_FROM_DEVICE); > > ret = *info & ECC_COMPLETE; > > } while (!ret); > > }
Thanks, Miquèl
| |