| Message ID | 20180823180926.444b34b5@xhacker.debian (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | solve SDHCI DWC MSHC 128MB DMA boundary limitation | expand |
On 23/08/18 13:09, 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 | 39 +++++++++++++++++++++++++++++ > 1 file changed, 39 insertions(+) > > diff --git a/drivers/mmc/host/sdhci-of-dwcmshc.c b/drivers/mmc/host/sdhci-of-dwcmshc.c > index 1b7cd144fb01..df0a3aeabe19 100644 > --- a/drivers/mmc/host/sdhci-of-dwcmshc.c > +++ b/drivers/mmc/host/sdhci-of-dwcmshc.c > @@ -8,21 +8,48 @@ > */ > > #include <linux/clk.h> > +#include <linux/mm.h> > #include <linux/module.h> > #include <linux/of.h> > +#include <linux/sizes.h> > > #include "sdhci-pltfm.h" > > +#define BOUNDARY_OK(addr, len) \ > + ((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 void dwcmshc_adma_write_desc(struct sdhci_host *host, void **desc, > + dma_addr_t addr, int len, unsigned int cmd) > +{ > + int tmplen, offset; > + > + if (likely(!len || BOUNDARY_OK(addr, len))) > + sdhci_adma_write_desc(host, desc, addr, len, cmd); Doesn't this need a return? i.e. return; } > + > + offset = addr & (SZ_128M - 1); > + tmplen = SZ_128M - offset; > + sdhci_adma_write_desc(host, desc, addr, tmplen, cmd); > + > + addr += tmplen; > + len -= tmplen; > + sdhci_adma_write_desc(host, desc, addr, len, cmd); > +} > + > 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 +63,24 @@ 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 table descriptor count 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 = DIV_ROUND_UP(totalram_pages, SZ_128M / PAGE_SIZE); You are assuming here that totalram_pages gives you the highest physical page number. Is that true? > + if (extra > SDHCI_MAX_SEGS) > + extra = SDHCI_MAX_SEGS; > + host->adma_table_cnt = SDHCI_MAX_SEGS * 2 + 1 + extra; That should be: host->adma_table_cnt += extra; > + > pltfm_host = sdhci_priv(host); > priv = sdhci_pltfm_priv(pltfm_host); > >
On Thu, 23 Aug 2018 14:51:26 +0300 Adrian Hunter wrote: > On 23/08/18 13:09, 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 | 39 +++++++++++++++++++++++++++++ > > 1 file changed, 39 insertions(+) > > > > diff --git a/drivers/mmc/host/sdhci-of-dwcmshc.c b/drivers/mmc/host/sdhci-of-dwcmshc.c > > index 1b7cd144fb01..df0a3aeabe19 100644 > > --- a/drivers/mmc/host/sdhci-of-dwcmshc.c > > +++ b/drivers/mmc/host/sdhci-of-dwcmshc.c > > @@ -8,21 +8,48 @@ > > */ > > > > #include <linux/clk.h> > > +#include <linux/mm.h> > > #include <linux/module.h> > > #include <linux/of.h> > > +#include <linux/sizes.h> > > > > #include "sdhci-pltfm.h" > > > > +#define BOUNDARY_OK(addr, len) \ > > + ((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 void dwcmshc_adma_write_desc(struct sdhci_host *host, void **desc, > > + dma_addr_t addr, int len, unsigned int cmd) > > +{ > > + int tmplen, offset; > > + > > + if (likely(!len || BOUNDARY_OK(addr, len))) > > + sdhci_adma_write_desc(host, desc, addr, len, cmd); > > Doesn't this need a return? i.e. > > return; oops, I made a mistake here. Pre v4, there's a return... Thanks so much. > } > > > + > > + offset = addr & (SZ_128M - 1); > > + tmplen = SZ_128M - offset; > > + sdhci_adma_write_desc(host, desc, addr, tmplen, cmd); > > + > > + addr += tmplen; > > + len -= tmplen; > > + sdhci_adma_write_desc(host, desc, addr, len, cmd); > > +} > > + > > 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 +63,24 @@ 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 table descriptor count 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 = DIV_ROUND_UP(totalram_pages, SZ_128M / PAGE_SIZE); > > You are assuming here that totalram_pages gives you the highest physical > page number. Is that true? Per my understanding, it's true. What I need is the MemTotal/PAGE_SIZE where Memtotal is from /proc/meminfo. After reading the code, I found this is totalram_pages as shown in si_meminfo() > > > + if (extra > SDHCI_MAX_SEGS) > > + extra = SDHCI_MAX_SEGS; > > + host->adma_table_cnt = SDHCI_MAX_SEGS * 2 + 1 + extra; > > That should be: > > host->adma_table_cnt += extra; yep, will do in v5 > > > + > > 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..df0a3aeabe19 100644 --- a/drivers/mmc/host/sdhci-of-dwcmshc.c +++ b/drivers/mmc/host/sdhci-of-dwcmshc.c @@ -8,21 +8,48 @@ */ #include <linux/clk.h> +#include <linux/mm.h> #include <linux/module.h> #include <linux/of.h> +#include <linux/sizes.h> #include "sdhci-pltfm.h" +#define BOUNDARY_OK(addr, len) \ + ((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 void dwcmshc_adma_write_desc(struct sdhci_host *host, void **desc, + dma_addr_t addr, int len, unsigned int cmd) +{ + int tmplen, offset; + + if (likely(!len || BOUNDARY_OK(addr, len))) + 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; + sdhci_adma_write_desc(host, desc, addr, len, cmd); +} + 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 +63,24 @@ 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 table descriptor count 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 = DIV_ROUND_UP(totalram_pages, SZ_128M / PAGE_SIZE); + if (extra > SDHCI_MAX_SEGS) + extra = SDHCI_MAX_SEGS; + host->adma_table_cnt = 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 | 39 +++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+)