Messages in this thread Patch in this message | | | Subject | Re: [RFC] mmc: meson-gx: use memcpy_to/fromio for dram-access-quirk | From | Robin Murphy <> | Date | Wed, 9 Jun 2021 15:45:36 +0100 |
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On 2021-06-09 14:07, Neil Armstrong wrote: > Hi, > > On 08/06/2021 17:50, Marek Szyprowski wrote: >> Hi >> >> On 08.06.2021 17:33, Neil Armstrong wrote: >>> It has been reported that usage of memcpy() to/from an iomem mapping is invalid, >>> and and recent arm64 memcpy update [1] triggers a memory abort when dram-access-quirk >>> is used on the G12A/G12B platforms. >>> >>> This adds a local sg_copy_to_buffer which makes usage of io versions of memcpy >>> when dram-access-quirk is enabled. >>> >>> Fixes: acdc8e71d9bb ("mmc: meson-gx: add dram-access-quirk") >>> Reported-by: Marek Szyprowski <m.szyprowski@samsung.com> >>> Suggested-by: Mark Rutland <mark.rutland@arm.com> >>> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com> >>> >>> [1] 285133040e6c ("arm64: Import latest memcpy()/memmove() implementation") >>> >>> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com> >>> --- >>> Hi Ulf, Marek, Mark, >>> >>> I haven't tested the patch yet, but should fix issue reported at [2]. >> >> Works fine here and fixed the issue. >> >> Tested-by: Marek Szyprowski <m.szyprowski@samsung.com> > > Thanks, I'll need to rework to pass an __iomem pointer to memcpy_to/fromio so sparse doesn't scream anymore.
Hmm, might it be worth factoring out general sg_copy_{to,from}_iomem() helpers? From a quick grep I found at least mv_cesa_sg_copy() already doing essentially the same thing as meson_mmc_copy_buffer().
Robin.
> > Neil > >> >>> Neil >>> >>> [2] https://lore.kernel.org/r/acb244ad-0759-5a96-c659-5c23003d3dcd@samsung.com >>> >>> drivers/mmc/host/meson-gx-mmc.c | 48 ++++++++++++++++++++++++++++++--- >>> 1 file changed, 44 insertions(+), 4 deletions(-) >>> >>> diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c >>> index b8b771b643cc..89ff6038092d 100644 >>> --- a/drivers/mmc/host/meson-gx-mmc.c >>> +++ b/drivers/mmc/host/meson-gx-mmc.c >>> @@ -742,6 +742,48 @@ static void meson_mmc_desc_chain_transfer(struct mmc_host *mmc, u32 cmd_cfg) >>> writel(start, host->regs + SD_EMMC_START); >>> } >>> >>> +/* local sg copy to buffer version with _to/fromio usage for dram_access_quirk */ >>> +static void meson_mmc_copy_buffer(struct meson_host *host, struct mmc_data *data, >>> + size_t buflen, bool to_buffer) >>> +{ >>> + unsigned int sg_flags = SG_MITER_ATOMIC; >>> + struct scatterlist *sgl = data->sg; >>> + unsigned int nents = data->sg_len; >>> + struct sg_mapping_iter miter; >>> + void *buf = host->bounce_buf; >>> + unsigned int offset = 0; >>> + >>> + if (to_buffer) >>> + sg_flags |= SG_MITER_FROM_SG; >>> + else >>> + sg_flags |= SG_MITER_TO_SG; >>> + >>> + sg_miter_start(&miter, sgl, nents, sg_flags); >>> + >>> + while ((offset < buflen) && sg_miter_next(&miter)) { >>> + unsigned int len; >>> + >>> + len = min(miter.length, buflen - offset); >>> + >>> + /* When dram_access_quirk, the bounce buffer is a iomem mapping */ >>> + if (host->dram_access_quirk) { >>> + if (to_buffer) >>> + memcpy_toio(buf + offset, miter.addr, len); >>> + else >>> + memcpy_fromio(miter.addr, buf + offset, len); >>> + } else { >>> + if (to_buffer) >>> + memcpy(buf + offset, miter.addr, len); >>> + else >>> + memcpy(miter.addr, buf + offset, len); >>> + } >>> + >>> + offset += len; >>> + } >>> + >>> + sg_miter_stop(&miter); >>> +} >>> + >>> static void meson_mmc_start_cmd(struct mmc_host *mmc, struct mmc_command *cmd) >>> { >>> struct meson_host *host = mmc_priv(mmc); >>> @@ -785,8 +827,7 @@ static void meson_mmc_start_cmd(struct mmc_host *mmc, struct mmc_command *cmd) >>> if (data->flags & MMC_DATA_WRITE) { >>> cmd_cfg |= CMD_CFG_DATA_WR; >>> WARN_ON(xfer_bytes > host->bounce_buf_size); >>> - sg_copy_to_buffer(data->sg, data->sg_len, >>> - host->bounce_buf, xfer_bytes); >>> + meson_mmc_copy_buffer(host, data, xfer_bytes, true); >>> dma_wmb(); >>> } >>> >>> @@ -955,8 +996,7 @@ static irqreturn_t meson_mmc_irq_thread(int irq, void *dev_id) >>> if (meson_mmc_bounce_buf_read(data)) { >>> xfer_bytes = data->blksz * data->blocks; >>> WARN_ON(xfer_bytes > host->bounce_buf_size); >>> - sg_copy_from_buffer(data->sg, data->sg_len, >>> - host->bounce_buf, xfer_bytes); >>> + meson_mmc_copy_buffer(host, data, xfer_bytes, false); >>> } >>> >>> next_cmd = meson_mmc_get_next_command(cmd); >> >> Best regards >> > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >
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