| Message ID | 20180725174749.6fc97d4d@xhacker.debian (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | solve SDHCI DWC MSHC 128MB DMA boundary limitation | expand |
On Wed, 25 Jul 2018 17:47:49 +0800 Jisheng Zhang wrote: > When using DMA, if the DMA addr spans 128MB boundary, we have to split > the DMA transfer into two so that each one doesn't exceed the boundary. > > Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com> > --- > drivers/mmc/host/sdhci-of-dwcmshc.c | 41 +++++++++++++++++++++++++++++ > 1 file changed, 41 insertions(+) > > diff --git a/drivers/mmc/host/sdhci-of-dwcmshc.c b/drivers/mmc/host/sdhci-of-dwcmshc.c > index 1b7cd144fb01..01b5cb772554 100644 > --- a/drivers/mmc/host/sdhci-of-dwcmshc.c > +++ b/drivers/mmc/host/sdhci-of-dwcmshc.c > @@ -13,16 +13,45 @@ > > #include "sdhci-pltfm.h" > > +#define BOUNDARY_OK(addr, len) \ > + ((addr | (SZ_128M - 1)) == ((addr + len) | (SZ_128M - 1))) this should be ((addr | (SZ_128M - 1)) == ((addr + len - 1) | (SZ_128M - 1))) > + > struct dwcmshc_priv { > struct clk *bus_clk; > }; > > +/* > + * if DMA addr spans 128MB boundary, we split the DMA transfer into two > + * so that the DMA transfer doesn't exceed the boundary. > + */ > +static unsigned int dwcmshc_adma_write_desc(struct sdhci_host *host, > + void *desc, dma_addr_t addr, > + int len, unsigned int cmd) > +{ > + int tmplen, offset; > + > + if (BOUNDARY_OK(addr, len)) > + return _sdhci_adma_write_desc(host, desc, addr, len, cmd); > + > + offset = addr & (SZ_128M - 1); > + tmplen = SZ_128M - offset; > + _sdhci_adma_write_desc(host, desc, addr, tmplen, cmd); > + > + addr += tmplen; > + len -= tmplen; > + desc += host->desc_sz; > + _sdhci_adma_write_desc(host, desc, addr, len, cmd); > + > + return host->desc_sz * 2; > +} > + > static const struct sdhci_ops sdhci_dwcmshc_ops = { > .set_clock = sdhci_set_clock, > .set_bus_width = sdhci_set_bus_width, > .set_uhs_signaling = sdhci_set_uhs_signaling, > .get_max_clock = sdhci_pltfm_clk_get_max_clock, > .reset = sdhci_reset, > + .adma_write_desc = dwcmshc_adma_write_desc, > }; > > static const struct sdhci_pltfm_data sdhci_dwcmshc_pdata = { > @@ -36,12 +65,24 @@ static int dwcmshc_probe(struct platform_device *pdev) > struct sdhci_host *host; > struct dwcmshc_priv *priv; > int err; > + u32 extra; > > host = sdhci_pltfm_init(pdev, &sdhci_dwcmshc_pdata, > sizeof(struct dwcmshc_priv)); > if (IS_ERR(host)) > return PTR_ERR(host); > > + /* > + * The DMA descriptor table number is calculated as the maximum > + * number of segments times 2, to allow for an alignment > + * descriptor for each segment, plus 1 for a nop end descriptor, > + * plus extra number for cross 128M boundary handling. > + */ > + extra = totalram_pages / (SZ_128M / PAGE_SIZE) + 1; will use DIV_ROUND_UP instead. > + if (extra > SDHCI_MAX_SEGS) > + extra = SDHCI_MAX_SEGS; > + host->adma_table_num = SDHCI_MAX_SEGS * 2 + 1 + extra; > + > pltfm_host = sdhci_priv(host); > priv = sdhci_pltfm_priv(pltfm_host); >
diff --git a/drivers/mmc/host/sdhci-of-dwcmshc.c b/drivers/mmc/host/sdhci-of-dwcmshc.c index 1b7cd144fb01..01b5cb772554 100644 --- a/drivers/mmc/host/sdhci-of-dwcmshc.c +++ b/drivers/mmc/host/sdhci-of-dwcmshc.c @@ -13,16 +13,45 @@ #include "sdhci-pltfm.h" +#define BOUNDARY_OK(addr, len) \ + ((addr | (SZ_128M - 1)) == ((addr + len) | (SZ_128M - 1))) + struct dwcmshc_priv { struct clk *bus_clk; }; +/* + * if DMA addr spans 128MB boundary, we split the DMA transfer into two + * so that the DMA transfer doesn't exceed the boundary. + */ +static unsigned int dwcmshc_adma_write_desc(struct sdhci_host *host, + void *desc, dma_addr_t addr, + int len, unsigned int cmd) +{ + int tmplen, offset; + + if (BOUNDARY_OK(addr, len)) + return _sdhci_adma_write_desc(host, desc, addr, len, cmd); + + offset = addr & (SZ_128M - 1); + tmplen = SZ_128M - offset; + _sdhci_adma_write_desc(host, desc, addr, tmplen, cmd); + + addr += tmplen; + len -= tmplen; + desc += host->desc_sz; + _sdhci_adma_write_desc(host, desc, addr, len, cmd); + + return host->desc_sz * 2; +} + static const struct sdhci_ops sdhci_dwcmshc_ops = { .set_clock = sdhci_set_clock, .set_bus_width = sdhci_set_bus_width, .set_uhs_signaling = sdhci_set_uhs_signaling, .get_max_clock = sdhci_pltfm_clk_get_max_clock, .reset = sdhci_reset, + .adma_write_desc = dwcmshc_adma_write_desc, }; static const struct sdhci_pltfm_data sdhci_dwcmshc_pdata = { @@ -36,12 +65,24 @@ static int dwcmshc_probe(struct platform_device *pdev) struct sdhci_host *host; struct dwcmshc_priv *priv; int err; + u32 extra; host = sdhci_pltfm_init(pdev, &sdhci_dwcmshc_pdata, sizeof(struct dwcmshc_priv)); if (IS_ERR(host)) return PTR_ERR(host); + /* + * The DMA descriptor table number is calculated as the maximum + * number of segments times 2, to allow for an alignment + * descriptor for each segment, plus 1 for a nop end descriptor, + * plus extra number for cross 128M boundary handling. + */ + extra = totalram_pages / (SZ_128M / PAGE_SIZE) + 1; + if (extra > SDHCI_MAX_SEGS) + extra = SDHCI_MAX_SEGS; + host->adma_table_num = SDHCI_MAX_SEGS * 2 + 1 + extra; + pltfm_host = sdhci_priv(host); priv = sdhci_pltfm_priv(pltfm_host);
When using DMA, if the DMA addr spans 128MB boundary, we have to split the DMA transfer into two so that each one doesn't exceed the boundary. Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com> --- drivers/mmc/host/sdhci-of-dwcmshc.c | 41 +++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+)