| Message ID | 78730daa2eaa66fa8089f196a52b51ce62579d1f.1532591566.git.baolin.wang@linaro.org (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | dmaengine: sprd: Support DMA link-list mode | expand |
On 26-07-18, 16:00, Baolin Wang wrote: > From: Eric Long <eric.long@spreadtrum.com> > > The Spreadtrum DMA can support the link-list transaction mode, which means > DMA controller can do transaction one by one automatically once we linked > these transaction by link-list register. > > Signed-off-by: Eric Long <eric.long@spreadtrum.com> > Signed-off-by: Baolin Wang <baolin.wang@linaro.org> > --- > drivers/dma/sprd-dma.c | 82 ++++++++++++++++++++++++++++++++++++++---- > include/linux/dma/sprd-dma.h | 69 +++++++++++++++++++++++++++++++++++ > 2 files changed, 144 insertions(+), 7 deletions(-) > > diff --git a/drivers/dma/sprd-dma.c b/drivers/dma/sprd-dma.c > index 55df0d4..649bd2c 100644 > --- a/drivers/dma/sprd-dma.c > +++ b/drivers/dma/sprd-dma.c > @@ -68,6 +68,7 @@ > > /* SPRD_DMA_CHN_CFG register definition */ > #define SPRD_DMA_CHN_EN BIT(0) > +#define SPRD_DMA_LINKLIST_EN BIT(4) > #define SPRD_DMA_WAIT_BDONE_OFFSET 24 > #define SPRD_DMA_DONOT_WAIT_BDONE 1 > > @@ -103,7 +104,7 @@ > #define SPRD_DMA_REQ_MODE_MASK GENMASK(1, 0) > #define SPRD_DMA_FIX_SEL_OFFSET 21 > #define SPRD_DMA_FIX_EN_OFFSET 20 > -#define SPRD_DMA_LLIST_END_OFFSET 19 > +#define SPRD_DMA_LLIST_END BIT(19) > #define SPRD_DMA_FRG_LEN_MASK GENMASK(16, 0) > > /* SPRD_DMA_CHN_BLK_LEN register definition */ > @@ -164,6 +165,7 @@ struct sprd_dma_desc { > struct sprd_dma_chn { > struct virt_dma_chan vc; > void __iomem *chn_base; > + struct sprd_dma_linklist linklist; > struct dma_slave_config slave_cfg; > u32 chn_num; > u32 dev_id; > @@ -582,7 +584,8 @@ static int sprd_dma_get_step(enum dma_slave_buswidth buswidth) > } > > static int sprd_dma_fill_desc(struct dma_chan *chan, > - struct sprd_dma_desc *sdesc, > + struct sprd_dma_chn_hw *hw, > + unsigned int sglen, int sg_index, > dma_addr_t src, dma_addr_t dst, u32 len, > enum dma_transfer_direction dir, > unsigned long flags, > @@ -590,7 +593,6 @@ static int sprd_dma_fill_desc(struct dma_chan *chan, > { > struct sprd_dma_dev *sdev = to_sprd_dma_dev(chan); > struct sprd_dma_chn *schan = to_sprd_dma_chan(chan); > - struct sprd_dma_chn_hw *hw = &sdesc->chn_hw; > u32 req_mode = (flags >> SPRD_DMA_REQ_SHIFT) & SPRD_DMA_REQ_MODE_MASK; > u32 int_mode = flags & SPRD_DMA_INT_MASK; > int src_datawidth, dst_datawidth, src_step, dst_step; > @@ -670,12 +672,58 @@ static int sprd_dma_fill_desc(struct dma_chan *chan, > temp |= (src_step & SPRD_DMA_TRSF_STEP_MASK) << SPRD_DMA_SRC_TRSF_STEP_OFFSET; > hw->trsf_step = temp; > > + /* link-list configuration */ > + if (schan->linklist.phy_addr) { > + if (sg_index == sglen - 1) > + hw->frg_len |= SPRD_DMA_LLIST_END; > + > + hw->cfg |= SPRD_DMA_LINKLIST_EN; > + hw->llist_ptr = schan->linklist.phy_addr + > + ((sg_index + 1) % sglen) * sizeof(*hw) + > + SPRD_DMA_CHN_SRC_ADDR; > + } else { > + hw->llist_ptr = 0; > + } > + > hw->frg_step = 0; > hw->src_blk_step = 0; > hw->des_blk_step = 0; > return 0; > } > > +static int sprd_dma_fill_linklist_desc(struct dma_chan *chan, > + unsigned int sglen, int sg_index, > + dma_addr_t src, dma_addr_t dst, u32 len, > + enum dma_transfer_direction dir, > + unsigned long flags, > + struct dma_slave_config *slave_cfg) > +{ > + struct sprd_dma_chn *schan = to_sprd_dma_chan(chan); > + struct sprd_dma_chn_hw *hw; > + > + if (sglen < 2 || !schan->linklist.virt_addr) > + return -EINVAL; why the limitation of 2 here? > + > + hw = (struct sprd_dma_chn_hw *)(schan->linklist.virt_addr + > + sg_index * sizeof(*hw)); > + > + return sprd_dma_fill_desc(chan, hw, sglen, sg_index, src, dst, len, dir, > + flags, slave_cfg); > +} > + > +static int sprd_dma_fill_chn_desc(struct dma_chan *chan, > + struct sprd_dma_desc *sdesc, > + dma_addr_t src, dma_addr_t dst, u32 len, > + enum dma_transfer_direction dir, > + unsigned long flags, > + struct dma_slave_config *slave_cfg) > +{ > + struct sprd_dma_chn_hw *hw = &sdesc->chn_hw; > + > + return sprd_dma_fill_desc(chan, hw, 0, 0, src, dst, len, dir, > + flags, slave_cfg); > +} this fn does not do much, so why not call sprd_dma_fill_desc() instead from caller! > + > static struct dma_async_tx_descriptor * > sprd_dma_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src, > size_t len, unsigned long flags) > @@ -744,10 +792,20 @@ static int sprd_dma_fill_desc(struct dma_chan *chan, > u32 len = 0; > int ret, i; > > - /* TODO: now we only support one sg for each DMA configuration. */ > - if (!is_slave_direction(dir) || sglen > 1) > + if (!is_slave_direction(dir)) > return NULL; > > + if (context) { > + struct sprd_dma_linklist *ll_cfg = > + (struct sprd_dma_linklist *)context; > + > + schan->linklist.phy_addr = ll_cfg->phy_addr; > + schan->linklist.virt_addr = ll_cfg->virt_addr; > + } else { > + schan->linklist.phy_addr = 0; > + schan->linklist.virt_addr = 0; > + } > + > sdesc = kzalloc(sizeof(*sdesc), GFP_NOWAIT); > if (!sdesc) > return NULL; > @@ -762,10 +820,20 @@ static int sprd_dma_fill_desc(struct dma_chan *chan, > src = slave_cfg->src_addr; > dst = sg_dma_address(sg); > } > + > + if (sglen < 2) > + break; ? > + > + ret = sprd_dma_fill_linklist_desc(chan, sglen, i, src, dst, len, > + dir, flags, slave_cfg); > + if (ret) { > + kfree(sdesc); > + return NULL; > + } > } > > - ret = sprd_dma_fill_desc(chan, sdesc, src, dst, len, dir, flags, > - slave_cfg); > + ret = sprd_dma_fill_chn_desc(chan, sdesc, src, dst, len, dir, flags, > + slave_cfg); > if (ret) { > kfree(sdesc); > return NULL; > diff --git a/include/linux/dma/sprd-dma.h b/include/linux/dma/sprd-dma.h > index b0115e3..c51c705 100644 > --- a/include/linux/dma/sprd-dma.h > +++ b/include/linux/dma/sprd-dma.h > @@ -58,4 +58,73 @@ enum sprd_dma_int_type { > SPRD_DMA_CFGERR_INT, > }; > > +/* > + * struct sprd_dma_linklist - DMA link-list address structure > + * @virt_addr: link-list virtual address to configure link-list node > + * @phy_addr: link-list physical address to link DMA transfer > + * > + * The Spreadtrum DMA controller supports the link-list mode, that means slaves > + * can supply several groups configurations (each configuration represents one > + * DMA transfer) saved in memory, and DMA controller will link these groups > + * configurations by writing the physical address of each configuration into the > + * link-list register. > + * > + * Just as shown below, the link-list pointer register will be pointed to the > + * phycial address of 'configuration 1', and the 'configuration 1' link-list /s/phycial/physical > + * pointer will be pointed to 'configuration 2', and so on. > + * Once trigger the DMA transfer, the DMA controller will load 'configureation /s/configureation/configuration > + * 1' to its registers automatically, after 'configuration 1' transation is /s/transation/transaction > + * done, DMA controller will load 'configuration 2' automatically, until all > + * DMA transactions are done. > + * > + * Note: The last link-list pointer should point to the physical address > + * of 'configuration 1', which can avoid DMA controller loads incorrect > + * configuration when the last configuration transaction is done. > + * > + * DMA controller linklist memory > + * ====================== ----------------------- > + *| | | configuration 1 |<--- > + *| DMA controller | ------->| | | > + *| | | | | | > + *| | | | | | > + *| | | | | | > + *| linklist pointer reg |---- ----| linklist pointer | | > + * ====================== | ----------------------- | > + * | | > + * | ----------------------- | > + * | | configuration 2 | | > + * --->| | | > + * | | | > + * | | | > + * | | | > + * ----| linklist pointer | | > + * | ----------------------- | > + * | | > + * | ----------------------- | > + * | | configuration 3 | | > + * --->| | | > + * | | | > + * | . | | > + * . | > + * . | > + * . | > + * | . | > + * | ----------------------- | > + * | | configuration n | | > + * --->| | | > + * | | | > + * | | | > + * | | | > + * | linklist pointer |---- > + * ----------------------- > + * > + * To support the link-list mode, DMA slaves should allocate one segment memory > + * from always-on IRAM or dma coherent memory to store these groups of DMA > + * configuration, and pass the virtual and physical addess to DMA controller. /s/addess/address > + */ > +struct sprd_dma_linklist { > + unsigned long virt_addr; > + phys_addr_t phy_addr; > +}; > + > #endif > -- > 1.7.9.5
Hi Vinod, (Comments from Eric Long) On 9 August 2018 at 10:32, Vinod <vkoul@kernel.org> wrote: > On 26-07-18, 16:00, Baolin Wang wrote: >> From: Eric Long <eric.long@spreadtrum.com> >> >> The Spreadtrum DMA can support the link-list transaction mode, which means >> DMA controller can do transaction one by one automatically once we linked >> these transaction by link-list register. >> >> Signed-off-by: Eric Long <eric.long@spreadtrum.com> >> Signed-off-by: Baolin Wang <baolin.wang@linaro.org> >> --- >> drivers/dma/sprd-dma.c | 82 ++++++++++++++++++++++++++++++++++++++---- >> include/linux/dma/sprd-dma.h | 69 +++++++++++++++++++++++++++++++++++ >> 2 files changed, 144 insertions(+), 7 deletions(-) >> >> diff --git a/drivers/dma/sprd-dma.c b/drivers/dma/sprd-dma.c >> index 55df0d4..649bd2c 100644 >> --- a/drivers/dma/sprd-dma.c >> +++ b/drivers/dma/sprd-dma.c >> @@ -68,6 +68,7 @@ >> >> /* SPRD_DMA_CHN_CFG register definition */ >> #define SPRD_DMA_CHN_EN BIT(0) >> +#define SPRD_DMA_LINKLIST_EN BIT(4) >> #define SPRD_DMA_WAIT_BDONE_OFFSET 24 >> #define SPRD_DMA_DONOT_WAIT_BDONE 1 >> >> @@ -103,7 +104,7 @@ >> #define SPRD_DMA_REQ_MODE_MASK GENMASK(1, 0) >> #define SPRD_DMA_FIX_SEL_OFFSET 21 >> #define SPRD_DMA_FIX_EN_OFFSET 20 >> -#define SPRD_DMA_LLIST_END_OFFSET 19 >> +#define SPRD_DMA_LLIST_END BIT(19) >> #define SPRD_DMA_FRG_LEN_MASK GENMASK(16, 0) >> >> /* SPRD_DMA_CHN_BLK_LEN register definition */ >> @@ -164,6 +165,7 @@ struct sprd_dma_desc { >> struct sprd_dma_chn { >> struct virt_dma_chan vc; >> void __iomem *chn_base; >> + struct sprd_dma_linklist linklist; >> struct dma_slave_config slave_cfg; >> u32 chn_num; >> u32 dev_id; >> @@ -582,7 +584,8 @@ static int sprd_dma_get_step(enum dma_slave_buswidth buswidth) >> } >> >> static int sprd_dma_fill_desc(struct dma_chan *chan, >> - struct sprd_dma_desc *sdesc, >> + struct sprd_dma_chn_hw *hw, >> + unsigned int sglen, int sg_index, >> dma_addr_t src, dma_addr_t dst, u32 len, >> enum dma_transfer_direction dir, >> unsigned long flags, >> @@ -590,7 +593,6 @@ static int sprd_dma_fill_desc(struct dma_chan *chan, >> { >> struct sprd_dma_dev *sdev = to_sprd_dma_dev(chan); >> struct sprd_dma_chn *schan = to_sprd_dma_chan(chan); >> - struct sprd_dma_chn_hw *hw = &sdesc->chn_hw; >> u32 req_mode = (flags >> SPRD_DMA_REQ_SHIFT) & SPRD_DMA_REQ_MODE_MASK; >> u32 int_mode = flags & SPRD_DMA_INT_MASK; >> int src_datawidth, dst_datawidth, src_step, dst_step; >> @@ -670,12 +672,58 @@ static int sprd_dma_fill_desc(struct dma_chan *chan, >> temp |= (src_step & SPRD_DMA_TRSF_STEP_MASK) << SPRD_DMA_SRC_TRSF_STEP_OFFSET; >> hw->trsf_step = temp; >> >> + /* link-list configuration */ >> + if (schan->linklist.phy_addr) { >> + if (sg_index == sglen - 1) >> + hw->frg_len |= SPRD_DMA_LLIST_END; >> + >> + hw->cfg |= SPRD_DMA_LINKLIST_EN; >> + hw->llist_ptr = schan->linklist.phy_addr + >> + ((sg_index + 1) % sglen) * sizeof(*hw) + >> + SPRD_DMA_CHN_SRC_ADDR; >> + } else { >> + hw->llist_ptr = 0; >> + } >> + >> hw->frg_step = 0; >> hw->src_blk_step = 0; >> hw->des_blk_step = 0; >> return 0; >> } >> >> +static int sprd_dma_fill_linklist_desc(struct dma_chan *chan, >> + unsigned int sglen, int sg_index, >> + dma_addr_t src, dma_addr_t dst, u32 len, >> + enum dma_transfer_direction dir, >> + unsigned long flags, >> + struct dma_slave_config *slave_cfg) >> +{ >> + struct sprd_dma_chn *schan = to_sprd_dma_chan(chan); >> + struct sprd_dma_chn_hw *hw; >> + >> + if (sglen < 2 || !schan->linklist.virt_addr) >> + return -EINVAL; > > why the limitation of 2 here? Spreadtrum DMA link-list mode needs more than 2 link-list configurations. If there is only one sg, it doesn't need to fill the link-list configuration. Moreover, we have valided the sg length in sprd_dma_prep_slave_sg(), so will remove the redundant validation here. > >> + >> + hw = (struct sprd_dma_chn_hw *)(schan->linklist.virt_addr + >> + sg_index * sizeof(*hw)); >> + >> + return sprd_dma_fill_desc(chan, hw, sglen, sg_index, src, dst, len, dir, >> + flags, slave_cfg); >> +} >> + >> +static int sprd_dma_fill_chn_desc(struct dma_chan *chan, >> + struct sprd_dma_desc *sdesc, >> + dma_addr_t src, dma_addr_t dst, u32 len, >> + enum dma_transfer_direction dir, >> + unsigned long flags, >> + struct dma_slave_config *slave_cfg) >> +{ >> + struct sprd_dma_chn_hw *hw = &sdesc->chn_hw; >> + >> + return sprd_dma_fill_desc(chan, hw, 0, 0, src, dst, len, dir, >> + flags, slave_cfg); >> +} > > this fn does not do much, so why not call sprd_dma_fill_desc() instead > from caller! OK, will fix it. > >> + >> static struct dma_async_tx_descriptor * >> sprd_dma_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src, >> size_t len, unsigned long flags) >> @@ -744,10 +792,20 @@ static int sprd_dma_fill_desc(struct dma_chan *chan, >> u32 len = 0; >> int ret, i; >> >> - /* TODO: now we only support one sg for each DMA configuration. */ >> - if (!is_slave_direction(dir) || sglen > 1) >> + if (!is_slave_direction(dir)) >> return NULL; >> >> + if (context) { >> + struct sprd_dma_linklist *ll_cfg = >> + (struct sprd_dma_linklist *)context; >> + >> + schan->linklist.phy_addr = ll_cfg->phy_addr; >> + schan->linklist.virt_addr = ll_cfg->virt_addr; >> + } else { >> + schan->linklist.phy_addr = 0; >> + schan->linklist.virt_addr = 0; >> + } >> + >> sdesc = kzalloc(sizeof(*sdesc), GFP_NOWAIT); >> if (!sdesc) >> return NULL; >> @@ -762,10 +820,20 @@ static int sprd_dma_fill_desc(struct dma_chan *chan, >> src = slave_cfg->src_addr; >> dst = sg_dma_address(sg); >> } >> + >> + if (sglen < 2) >> + break; > > ? Like I said above, dma link-list mode needs more than 2 configurations, I will add some comments to explain why. > >> + >> + ret = sprd_dma_fill_linklist_desc(chan, sglen, i, src, dst, len, >> + dir, flags, slave_cfg); >> + if (ret) { >> + kfree(sdesc); >> + return NULL; >> + } >> } >> >> - ret = sprd_dma_fill_desc(chan, sdesc, src, dst, len, dir, flags, >> - slave_cfg); >> + ret = sprd_dma_fill_chn_desc(chan, sdesc, src, dst, len, dir, flags, >> + slave_cfg); >> if (ret) { >> kfree(sdesc); >> return NULL; >> diff --git a/include/linux/dma/sprd-dma.h b/include/linux/dma/sprd-dma.h >> index b0115e3..c51c705 100644 >> --- a/include/linux/dma/sprd-dma.h >> +++ b/include/linux/dma/sprd-dma.h >> @@ -58,4 +58,73 @@ enum sprd_dma_int_type { >> SPRD_DMA_CFGERR_INT, >> }; >> >> +/* >> + * struct sprd_dma_linklist - DMA link-list address structure >> + * @virt_addr: link-list virtual address to configure link-list node >> + * @phy_addr: link-list physical address to link DMA transfer >> + * >> + * The Spreadtrum DMA controller supports the link-list mode, that means slaves >> + * can supply several groups configurations (each configuration represents one >> + * DMA transfer) saved in memory, and DMA controller will link these groups >> + * configurations by writing the physical address of each configuration into the >> + * link-list register. >> + * >> + * Just as shown below, the link-list pointer register will be pointed to the >> + * phycial address of 'configuration 1', and the 'configuration 1' link-list > > /s/phycial/physical Sorry for typos and will fix. > >> + * pointer will be pointed to 'configuration 2', and so on. >> + * Once trigger the DMA transfer, the DMA controller will load 'configureation > > /s/configureation/configuration Will fix. > >> + * 1' to its registers automatically, after 'configuration 1' transation is > > /s/transation/transaction Will fix. > >> + * done, DMA controller will load 'configuration 2' automatically, until all >> + * DMA transactions are done. >> + * >> + * Note: The last link-list pointer should point to the physical address >> + * of 'configuration 1', which can avoid DMA controller loads incorrect >> + * configuration when the last configuration transaction is done. >> + * >> + * DMA controller linklist memory >> + * ====================== ----------------------- >> + *| | | configuration 1 |<--- >> + *| DMA controller | ------->| | | >> + *| | | | | | >> + *| | | | | | >> + *| | | | | | >> + *| linklist pointer reg |---- ----| linklist pointer | | >> + * ====================== | ----------------------- | >> + * | | >> + * | ----------------------- | >> + * | | configuration 2 | | >> + * --->| | | >> + * | | | >> + * | | | >> + * | | | >> + * ----| linklist pointer | | >> + * | ----------------------- | >> + * | | >> + * | ----------------------- | >> + * | | configuration 3 | | >> + * --->| | | >> + * | | | >> + * | . | | >> + * . | >> + * . | >> + * . | >> + * | . | >> + * | ----------------------- | >> + * | | configuration n | | >> + * --->| | | >> + * | | | >> + * | | | >> + * | | | >> + * | linklist pointer |---- >> + * ----------------------- >> + * >> + * To support the link-list mode, DMA slaves should allocate one segment memory >> + * from always-on IRAM or dma coherent memory to store these groups of DMA >> + * configuration, and pass the virtual and physical addess to DMA controller. > > /s/addess/address Will fix in next version. Thanks for your comments.
diff --git a/drivers/dma/sprd-dma.c b/drivers/dma/sprd-dma.c index 55df0d4..649bd2c 100644 --- a/drivers/dma/sprd-dma.c +++ b/drivers/dma/sprd-dma.c @@ -68,6 +68,7 @@ /* SPRD_DMA_CHN_CFG register definition */ #define SPRD_DMA_CHN_EN BIT(0) +#define SPRD_DMA_LINKLIST_EN BIT(4) #define SPRD_DMA_WAIT_BDONE_OFFSET 24 #define SPRD_DMA_DONOT_WAIT_BDONE 1 @@ -103,7 +104,7 @@ #define SPRD_DMA_REQ_MODE_MASK GENMASK(1, 0) #define SPRD_DMA_FIX_SEL_OFFSET 21 #define SPRD_DMA_FIX_EN_OFFSET 20 -#define SPRD_DMA_LLIST_END_OFFSET 19 +#define SPRD_DMA_LLIST_END BIT(19) #define SPRD_DMA_FRG_LEN_MASK GENMASK(16, 0) /* SPRD_DMA_CHN_BLK_LEN register definition */ @@ -164,6 +165,7 @@ struct sprd_dma_desc { struct sprd_dma_chn { struct virt_dma_chan vc; void __iomem *chn_base; + struct sprd_dma_linklist linklist; struct dma_slave_config slave_cfg; u32 chn_num; u32 dev_id; @@ -582,7 +584,8 @@ static int sprd_dma_get_step(enum dma_slave_buswidth buswidth) } static int sprd_dma_fill_desc(struct dma_chan *chan, - struct sprd_dma_desc *sdesc, + struct sprd_dma_chn_hw *hw, + unsigned int sglen, int sg_index, dma_addr_t src, dma_addr_t dst, u32 len, enum dma_transfer_direction dir, unsigned long flags, @@ -590,7 +593,6 @@ static int sprd_dma_fill_desc(struct dma_chan *chan, { struct sprd_dma_dev *sdev = to_sprd_dma_dev(chan); struct sprd_dma_chn *schan = to_sprd_dma_chan(chan); - struct sprd_dma_chn_hw *hw = &sdesc->chn_hw; u32 req_mode = (flags >> SPRD_DMA_REQ_SHIFT) & SPRD_DMA_REQ_MODE_MASK; u32 int_mode = flags & SPRD_DMA_INT_MASK; int src_datawidth, dst_datawidth, src_step, dst_step; @@ -670,12 +672,58 @@ static int sprd_dma_fill_desc(struct dma_chan *chan, temp |= (src_step & SPRD_DMA_TRSF_STEP_MASK) << SPRD_DMA_SRC_TRSF_STEP_OFFSET; hw->trsf_step = temp; + /* link-list configuration */ + if (schan->linklist.phy_addr) { + if (sg_index == sglen - 1) + hw->frg_len |= SPRD_DMA_LLIST_END; + + hw->cfg |= SPRD_DMA_LINKLIST_EN; + hw->llist_ptr = schan->linklist.phy_addr + + ((sg_index + 1) % sglen) * sizeof(*hw) + + SPRD_DMA_CHN_SRC_ADDR; + } else { + hw->llist_ptr = 0; + } + hw->frg_step = 0; hw->src_blk_step = 0; hw->des_blk_step = 0; return 0; } +static int sprd_dma_fill_linklist_desc(struct dma_chan *chan, + unsigned int sglen, int sg_index, + dma_addr_t src, dma_addr_t dst, u32 len, + enum dma_transfer_direction dir, + unsigned long flags, + struct dma_slave_config *slave_cfg) +{ + struct sprd_dma_chn *schan = to_sprd_dma_chan(chan); + struct sprd_dma_chn_hw *hw; + + if (sglen < 2 || !schan->linklist.virt_addr) + return -EINVAL; + + hw = (struct sprd_dma_chn_hw *)(schan->linklist.virt_addr + + sg_index * sizeof(*hw)); + + return sprd_dma_fill_desc(chan, hw, sglen, sg_index, src, dst, len, dir, + flags, slave_cfg); +} + +static int sprd_dma_fill_chn_desc(struct dma_chan *chan, + struct sprd_dma_desc *sdesc, + dma_addr_t src, dma_addr_t dst, u32 len, + enum dma_transfer_direction dir, + unsigned long flags, + struct dma_slave_config *slave_cfg) +{ + struct sprd_dma_chn_hw *hw = &sdesc->chn_hw; + + return sprd_dma_fill_desc(chan, hw, 0, 0, src, dst, len, dir, + flags, slave_cfg); +} + static struct dma_async_tx_descriptor * sprd_dma_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src, size_t len, unsigned long flags) @@ -744,10 +792,20 @@ static int sprd_dma_fill_desc(struct dma_chan *chan, u32 len = 0; int ret, i; - /* TODO: now we only support one sg for each DMA configuration. */ - if (!is_slave_direction(dir) || sglen > 1) + if (!is_slave_direction(dir)) return NULL; + if (context) { + struct sprd_dma_linklist *ll_cfg = + (struct sprd_dma_linklist *)context; + + schan->linklist.phy_addr = ll_cfg->phy_addr; + schan->linklist.virt_addr = ll_cfg->virt_addr; + } else { + schan->linklist.phy_addr = 0; + schan->linklist.virt_addr = 0; + } + sdesc = kzalloc(sizeof(*sdesc), GFP_NOWAIT); if (!sdesc) return NULL; @@ -762,10 +820,20 @@ static int sprd_dma_fill_desc(struct dma_chan *chan, src = slave_cfg->src_addr; dst = sg_dma_address(sg); } + + if (sglen < 2) + break; + + ret = sprd_dma_fill_linklist_desc(chan, sglen, i, src, dst, len, + dir, flags, slave_cfg); + if (ret) { + kfree(sdesc); + return NULL; + } } - ret = sprd_dma_fill_desc(chan, sdesc, src, dst, len, dir, flags, - slave_cfg); + ret = sprd_dma_fill_chn_desc(chan, sdesc, src, dst, len, dir, flags, + slave_cfg); if (ret) { kfree(sdesc); return NULL; diff --git a/include/linux/dma/sprd-dma.h b/include/linux/dma/sprd-dma.h index b0115e3..c51c705 100644 --- a/include/linux/dma/sprd-dma.h +++ b/include/linux/dma/sprd-dma.h @@ -58,4 +58,73 @@ enum sprd_dma_int_type { SPRD_DMA_CFGERR_INT, }; +/* + * struct sprd_dma_linklist - DMA link-list address structure + * @virt_addr: link-list virtual address to configure link-list node + * @phy_addr: link-list physical address to link DMA transfer + * + * The Spreadtrum DMA controller supports the link-list mode, that means slaves + * can supply several groups configurations (each configuration represents one + * DMA transfer) saved in memory, and DMA controller will link these groups + * configurations by writing the physical address of each configuration into the + * link-list register. + * + * Just as shown below, the link-list pointer register will be pointed to the + * phycial address of 'configuration 1', and the 'configuration 1' link-list + * pointer will be pointed to 'configuration 2', and so on. + * Once trigger the DMA transfer, the DMA controller will load 'configureation + * 1' to its registers automatically, after 'configuration 1' transation is + * done, DMA controller will load 'configuration 2' automatically, until all + * DMA transactions are done. + * + * Note: The last link-list pointer should point to the physical address + * of 'configuration 1', which can avoid DMA controller loads incorrect + * configuration when the last configuration transaction is done. + * + * DMA controller linklist memory + * ====================== ----------------------- + *| | | configuration 1 |<--- + *| DMA controller | ------->| | | + *| | | | | | + *| | | | | | + *| | | | | | + *| linklist pointer reg |---- ----| linklist pointer | | + * ====================== | ----------------------- | + * | | + * | ----------------------- | + * | | configuration 2 | | + * --->| | | + * | | | + * | | | + * | | | + * ----| linklist pointer | | + * | ----------------------- | + * | | + * | ----------------------- | + * | | configuration 3 | | + * --->| | | + * | | | + * | . | | + * . | + * . | + * . | + * | . | + * | ----------------------- | + * | | configuration n | | + * --->| | | + * | | | + * | | | + * | | | + * | linklist pointer |---- + * ----------------------- + * + * To support the link-list mode, DMA slaves should allocate one segment memory + * from always-on IRAM or dma coherent memory to store these groups of DMA + * configuration, and pass the virtual and physical addess to DMA controller. + */ +struct sprd_dma_linklist { + unsigned long virt_addr; + phys_addr_t phy_addr; +}; + #endif