> Date: Sun, 31 Dec 2017 13:46:44 +0200
> From: Artturi Alm <artturi....@gmail.com>
>
> On Sat, Dec 30, 2017 at 08:39:42PM +0200, Artturi Alm wrote:
> > Hi,
> >
> > porting sdhc driver(bcm2835_emmc.c) from NetBSD does lack something
> > like this, among possibly few other (small?) changes, but consider this
> > as a step towards.
> >
> > Comments? to keep changes minimal/safe/easy to review like below, or to
> > backport in bigger chunks?
> >
> > -Artturi
> >
>
> Hi,
>
> while working out the second step i came to a conclusion,
> that the diff should work in theory like below,
> and be easier to review w/o the use of SHF_USE_DMA flag.
>
> any comments?
Is the BCM2835 hardware really a standard SDHC controller? If there
are too many quirks, I tend to prefer a seperate driver instead of a
bit of SoC-specific glue for shdc(4).
Otherwise this mostly makes sense to me as infrastructure to use an
external DMA controller. I don't think we should at it unless there
is an actual user though.
Cheers,
Mark
> diff --git a/sys/dev/sdmmc/sdhc.c b/sys/dev/sdmmc/sdhc.c
> index c242a600d4a..f65790ff581 100644
> --- a/sys/dev/sdmmc/sdhc.c
> +++ b/sys/dev/sdmmc/sdhc.c
> @@ -187,6 +187,10 @@ sdhc_host_found(struct sdhc_softc *sc, bus_space_tag_t
> iot,
> /* Use DMA if the host system and the controller support it. */
> if (usedma && ISSET(caps, SDHC_ADMA2_SUPP))
> SET(hp->flags, SHF_USE_DMA);
> + if (!usedma)
> + sc->sc_extdma_transfer = NULL;
> + else if (sc->sc_extdma_transfer)
> + CLR(hp->flags, SHF_USE_DMA);
>
> /*
> * Determine the base clock frequency. (2.2.24)
> @@ -302,6 +306,8 @@ sdhc_host_found(struct sdhc_softc *sc, bus_space_tag_t
> iot,
> saa.dmat = sc->sc_dmat;
> if (ISSET(hp->flags, SHF_USE_DMA))
> saa.caps |= SMC_CAPS_DMA;
> + else if (sc->sc_extdma_transfer)
> + saa.caps |= SMC_CAPS_DMA;
>
> if (ISSET(caps, SDHC_HIGH_SPEED_SUPP))
> saa.caps |= SMC_CAPS_SD_HIGHSPEED;
> @@ -939,6 +945,16 @@ sdhc_transfer_data(struct sdhc_host *hp, struct
> sdmmc_command *cmd)
> if (cmd->c_dmamap) {
> int status;
>
> + if (sc->sc_extdma_transfer != NULL) {
> + error = sc->sc_extdma_transfer(sc, cmd);
> + if (error == 0 && !sdhc_wait_intr(hp,
> + SDHC_TRANSFER_COMPLETE, SDHC_DMA_TIMEOUT)) {
> + DPRINTF(1,("%s: timeout\n", __func__));
> + error = ETIMEDOUT;
> + }
> + goto done;
> + }
> +
> error = 0;
> for (;;) {
> status = sdhc_wait_intr(hp,
> diff --git a/sys/dev/sdmmc/sdhcvar.h b/sys/dev/sdmmc/sdhcvar.h
> index 9d4d759a2bc..5c0f462cfe6 100644
> --- a/sys/dev/sdmmc/sdhcvar.h
> +++ b/sys/dev/sdmmc/sdhcvar.h
> @@ -22,6 +22,7 @@
> #include <machine/bus.h>
>
> struct sdhc_host;
> +struct sdmmc_command;
>
> struct sdhc_softc {
> struct device sc_dev;
> @@ -33,6 +34,7 @@ struct sdhc_softc {
>
> int (*sc_card_detect)(struct sdhc_softc *);
> int (*sc_signal_voltage)(struct sdhc_softc *, int);
> + int (*sc_extdma_transfer)(struct sdhc_softc *, struct sdmmc_command *);
> };
>
> /* Host controller functions called by the attachment driver. */
>
