| Message ID | 1530523083-2106-1-git-send-email-yoshihiro.shimoda.uh@renesas.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
On 02-07-18, 18:18, Yoshihiro Shimoda wrote: > This patch fixes an issue that unexpected retransfering happens > if TCR is set to 0 before rcar_dmac_sync_tcr() writes DE bit to > the CHCR register. For example, sh-sci driver can reproduce this > issue like below: > > In rx_timer_fn(): /* CHCR DE bit may be set to 1 */ > dmaengine_tx_status() > rcar_dmac_tx_status() > rcar_dmac_chan_get_residue() > rcar_dmac_sync_tcr() /* TCR is possible to be set to 0 */ > > According to the description of commit 73a47bd0da66 ("dmaengine: > rcar-dmac: use TCRB instead of TCR for residue"), "this buffered data > will be transferred if CHCR::DE bit was cleared". So, this patch > doesn't need to check TCRB register. > > Fixes: 73a47bd0da66 ("dmaengine: rcar-dmac: use TCRB instead of TCR for residue") > Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> > --- > This patch is based on the latest slave-dma / fixes branch. > > This issue can be reproduced by the following commands on r8a7795 > Salvator-XS and Windows Teraterm :) : > # stty 921600 > (Change Teraterm baud rate) > # cat > rx.txt > (Send 5MiB file by Teraterm. After a few minutes later, we cannot > input any commands by the serial console.) Ack/tested-by ..? > > drivers/dma/sh/rcar-dmac.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c > index 2a2ccd9..8305a1c 100644 > --- a/drivers/dma/sh/rcar-dmac.c > +++ b/drivers/dma/sh/rcar-dmac.c > @@ -774,8 +774,9 @@ static void rcar_dmac_sync_tcr(struct rcar_dmac_chan *chan) > /* make sure all remaining data was flushed */ > rcar_dmac_chcr_de_barrier(chan); > > - /* back DE */ > - rcar_dmac_chan_write(chan, RCAR_DMACHCR, chcr); > + /* back DE if remain data exists */ > + if (rcar_dmac_chan_read(chan, RCAR_DMATCR)) > + rcar_dmac_chan_write(chan, RCAR_DMACHCR, chcr); > } > > static void rcar_dmac_chan_halt(struct rcar_dmac_chan *chan) > -- > 1.9.1 > > -- > To unsubscribe from this list: send the line "unsubscribe dmaengine" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
On 02-07-18, 18:18, Yoshihiro Shimoda wrote: > This patch fixes an issue that unexpected retransfering happens > if TCR is set to 0 before rcar_dmac_sync_tcr() writes DE bit to > the CHCR register. For example, sh-sci driver can reproduce this > issue like below: > > In rx_timer_fn(): /* CHCR DE bit may be set to 1 */ > dmaengine_tx_status() > rcar_dmac_tx_status() > rcar_dmac_chan_get_residue() > rcar_dmac_sync_tcr() /* TCR is possible to be set to 0 */ > > According to the description of commit 73a47bd0da66 ("dmaengine: > rcar-dmac: use TCRB instead of TCR for residue"), "this buffered data > will be transferred if CHCR::DE bit was cleared". So, this patch > doesn't need to check TCRB register. > > Fixes: 73a47bd0da66 ("dmaengine: rcar-dmac: use TCRB instead of TCR for residue") > Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> > --- > This patch is based on the latest slave-dma / fixes branch. > > This issue can be reproduced by the following commands on r8a7795 > Salvator-XS and Windows Teraterm :) : > # stty 921600 > (Change Teraterm baud rate) > # cat > rx.txt > (Send 5MiB file by Teraterm. After a few minutes later, we cannot > input any commands by the serial console.) Applied after fixing subsystem name
On Mon, Jul 2, 2018 at 11:41 AM Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> wrote: > This patch fixes an issue that unexpected retransfering happens > if TCR is set to 0 before rcar_dmac_sync_tcr() writes DE bit to > the CHCR register. For example, sh-sci driver can reproduce this > issue like below: > > In rx_timer_fn(): /* CHCR DE bit may be set to 1 */ > dmaengine_tx_status() > rcar_dmac_tx_status() > rcar_dmac_chan_get_residue() > rcar_dmac_sync_tcr() /* TCR is possible to be set to 0 */ > > According to the description of commit 73a47bd0da66 ("dmaengine: > rcar-dmac: use TCRB instead of TCR for residue"), "this buffered data > will be transferred if CHCR::DE bit was cleared". So, this patch > doesn't need to check TCRB register. > > Fixes: 73a47bd0da66 ("dmaengine: rcar-dmac: use TCRB instead of TCR for residue") > Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> Looks reasonable Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Gr{oetje,eeting}s, Geert
diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c index 2a2ccd9..8305a1c 100644 --- a/drivers/dma/sh/rcar-dmac.c +++ b/drivers/dma/sh/rcar-dmac.c @@ -774,8 +774,9 @@ static void rcar_dmac_sync_tcr(struct rcar_dmac_chan *chan) /* make sure all remaining data was flushed */ rcar_dmac_chcr_de_barrier(chan); - /* back DE */ - rcar_dmac_chan_write(chan, RCAR_DMACHCR, chcr); + /* back DE if remain data exists */ + if (rcar_dmac_chan_read(chan, RCAR_DMATCR)) + rcar_dmac_chan_write(chan, RCAR_DMACHCR, chcr); } static void rcar_dmac_chan_halt(struct rcar_dmac_chan *chan)
This patch fixes an issue that unexpected retransfering happens if TCR is set to 0 before rcar_dmac_sync_tcr() writes DE bit to the CHCR register. For example, sh-sci driver can reproduce this issue like below: In rx_timer_fn(): /* CHCR DE bit may be set to 1 */ dmaengine_tx_status() rcar_dmac_tx_status() rcar_dmac_chan_get_residue() rcar_dmac_sync_tcr() /* TCR is possible to be set to 0 */ According to the description of commit 73a47bd0da66 ("dmaengine: rcar-dmac: use TCRB instead of TCR for residue"), "this buffered data will be transferred if CHCR::DE bit was cleared". So, this patch doesn't need to check TCRB register. Fixes: 73a47bd0da66 ("dmaengine: rcar-dmac: use TCRB instead of TCR for residue") Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> --- This patch is based on the latest slave-dma / fixes branch. This issue can be reproduced by the following commands on r8a7795 Salvator-XS and Windows Teraterm :) : # stty 921600 (Change Teraterm baud rate) # cat > rx.txt (Send 5MiB file by Teraterm. After a few minutes later, we cannot input any commands by the serial console.) drivers/dma/sh/rcar-dmac.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)