Hi Adrian,
On Fri, 9 Dec 2022 09:23:05 +0200, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote:
> On 5/12/22 12:59, Vadym Kochan wrote:
> > There is a limitation on AC5 SoC that mmc controller
> > can't have DMA access over 2G memory, so use SDMA with
> > a bounce buffer. Swiotlb can't help because on arm64 arch
> > it reserves memblock's at the end of the memory.
> >
> > Additionally set mask to 34 bit since on AC5 SoC RAM starts
> > at 0x2_00000000.
>
> Can you explain more about how a 34-bit DMA mask works when
> SDMA only supports 32-bit addresses?
>
So, after I set
> > + host->flags &= ~SDHCI_USE_64_BIT_DMA;
then sdhc core sets mask to 32 bit, but then dma_map fails to map
bounce buffer because the base address is higher than 32bit - 0x2_00000000,
and 34bit mask fixed it.
> >
> > Co-developed-by: Elad Nachman <enachman@xxxxxxxxxxx>
> > Signed-off-by: Elad Nachman <enachman@xxxxxxxxxxx>
> > Signed-off-by: Vadym Kochan <vadym.kochan@xxxxxxxxxxx>
> > ---
> > drivers/mmc/host/sdhci-xenon.c | 38 ++++++++++++++++++++++++++++++++++
> > drivers/mmc/host/sdhci-xenon.h | 3 ++-
> > 2 files changed, 40 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/mmc/host/sdhci-xenon.c b/drivers/mmc/host/sdhci-xenon.c
> > index 08e838400b52..5f3db0425674 100644
> > --- a/drivers/mmc/host/sdhci-xenon.c
> > +++ b/drivers/mmc/host/sdhci-xenon.c
> > @@ -13,7 +13,9 @@
> >
> > #include <linux/acpi.h>
> > #include <linux/delay.h>
> > +#include <linux/dma-mapping.h>
> > #include <linux/ktime.h>
> > +#include <linux/mm.h>
> > #include <linux/module.h>
> > #include <linux/of.h>
> > #include <linux/pm.h>
> > @@ -253,6 +255,22 @@ static unsigned int xenon_get_max_clock(struct sdhci_host *host)
> > return pltfm_host->clock;
> > }
> >
> > +static int xenon_set_dma_mask(struct sdhci_host *host)
> > +{
> > + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> > + struct xenon_priv *priv = sdhci_pltfm_priv(pltfm_host);
> > + struct mmc_host *mmc = host->mmc;
> > + struct device *dev = mmc_dev(mmc);
> > +
> > + if (priv->hw_version == XENON_AC5) {
> > + host->flags &= ~SDHCI_USE_64_BIT_DMA;
> > +
> > + return dma_set_mask_and_coherent(dev, DMA_BIT_MASK(34));
> > + }
> > +
> > + return sdhci_set_dma_mask(host);
> > +}
> > +
> > static const struct sdhci_ops sdhci_xenon_ops = {
> > .voltage_switch = xenon_voltage_switch,
> > .set_clock = sdhci_set_clock,
> > @@ -261,6 +279,7 @@ static const struct sdhci_ops sdhci_xenon_ops = {
> > .reset = xenon_reset,
> > .set_uhs_signaling = xenon_set_uhs_signaling,
> > .get_max_clock = xenon_get_max_clock,
> > + .set_dma_mask = xenon_set_dma_mask,
> > };
> >
> > static const struct sdhci_pltfm_data sdhci_xenon_pdata = {
> > @@ -486,6 +505,18 @@ static void xenon_sdhc_unprepare(struct sdhci_host *host)
> > xenon_disable_sdhc(host, sdhc_id);
> > }
> >
> > +static int xenon_ac5_probe(struct sdhci_host *host)
> > +{
> > + struct sysinfo si;
> > +
> > + si_meminfo(&si);
> > +
> > + if ((si.totalram * si.mem_unit) > SZ_2G)
> > + host->quirks |= SDHCI_QUIRK_BROKEN_ADMA;
> > +
> > + return 0;
> > +}
> > +
> > static int xenon_probe(struct platform_device *pdev)
> > {
> > struct sdhci_pltfm_host *pltfm_host;
> > @@ -533,6 +564,12 @@ static int xenon_probe(struct platform_device *pdev)
> > }
> > }
> >
> > + if (priv->hw_version == XENON_AC5) {
> > + err = xenon_ac5_probe(host);
> > + if (err)
> > + goto err_clk_axi;
> > + }
> > +
> > err = mmc_of_parse(host->mmc);
> > if (err)
> > goto err_clk_axi;
> > @@ -682,6 +719,7 @@ static const struct of_device_id sdhci_xenon_dt_ids[] = {
> > { .compatible = "marvell,armada-ap807-sdhci", .data = (void *)XENON_AP807},
> > { .compatible = "marvell,armada-cp110-sdhci", .data = (void *)XENON_CP110},
> > { .compatible = "marvell,armada-3700-sdhci", .data = (void *)XENON_A3700},
> > + { .compatible = "marvell,ac5-sdhci", .data = (void *)XENON_AC5},
> > {}
> > };
> > MODULE_DEVICE_TABLE(of, sdhci_xenon_dt_ids);
> > diff --git a/drivers/mmc/host/sdhci-xenon.h b/drivers/mmc/host/sdhci-xenon.h
> > index 3e9c6c908a79..0460d97aad26 100644
> > --- a/drivers/mmc/host/sdhci-xenon.h
> > +++ b/drivers/mmc/host/sdhci-xenon.h
> > @@ -57,7 +57,8 @@ enum xenon_variant {
> > XENON_A3700,
> > XENON_AP806,
> > XENON_AP807,
> > - XENON_CP110
> > + XENON_CP110,
> > + XENON_AC5
> > };
> >
> > struct xenon_priv {
>
Regards,
