| Message ID | 1517644697-30806-8-git-send-email-absahu@codeaurora.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Major code reorganization to make all i2c transfers working | expand |
On 2/3/2018 1:28 PM, Abhishek Sahu wrote: > Currently each message length in complete transfer is being > checked for determining DMA mode and if any of the message length > is less than FIFO length then non DMA mode is being used which > will increase overhead. DMA can be used for any length and it > should be determined with complete transfer length. Now, this > patch introduces DMA threshold length and the transfer will be > done in DMA mode if the total length is greater than this > threshold length. > > Signed-off-by: Abhishek Sahu <absahu@codeaurora.org> > --- > drivers/i2c/busses/i2c-qup.c | 15 +++++++++------ > 1 file changed, 9 insertions(+), 6 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-qup.c b/drivers/i2c/busses/i2c-qup.c > index 6227a5c..a91fc70 100644 > --- a/drivers/i2c/busses/i2c-qup.c > +++ b/drivers/i2c/busses/i2c-qup.c > @@ -192,6 +192,8 @@ struct qup_i2c_dev { > bool is_dma; > /* To check if the current transfer is using DMA */ > bool use_dma; > + /* The threshold length above which DMA will be used */ > + unsigned int dma_threshold; > struct dma_pool *dpool; > struct qup_i2c_tag start_tag; > struct qup_i2c_bam brx; > @@ -1294,7 +1296,8 @@ static int qup_i2c_xfer_v2(struct i2c_adapter *adap, > int num) > { > struct qup_i2c_dev *qup = i2c_get_adapdata(adap); > - int ret, len, idx = 0; > + int ret, idx = 0; > + unsigned int total_len = 0; > > qup->bus_err = 0; > qup->qup_err = 0; > @@ -1320,14 +1323,13 @@ static int qup_i2c_xfer_v2(struct i2c_adapter *adap, > goto out; > } > > - len = (msgs[idx].len > qup->out_fifo_sz) || > - (msgs[idx].len > qup->in_fifo_sz); > - > - if (is_vmalloc_addr(msgs[idx].buf) || !len) > + if (is_vmalloc_addr(msgs[idx].buf)) > break; > + > + total_len += msgs[idx].len; > } > > - if (idx == num) > + if (idx == num && total_len > qup->dma_threshold) > qup->use_dma = true; > } > > @@ -1587,6 +1589,7 @@ static int qup_i2c_probe(struct platform_device *pdev) > > size = QUP_INPUT_FIFO_SIZE(io_mode); > qup->in_fifo_sz = qup->in_blk_sz * (2 << size); > + qup->dma_threshold = min(qup->out_fifo_sz, qup->in_fifo_sz); The patch is fine. small nit, you can avoid this global dma_threshold. Instead have it locally in qup_i2c_xfer_v2 itself. Regards, Sricharan
On 2018-02-16 10:05, Sricharan R wrote: > On 2/3/2018 1:28 PM, Abhishek Sahu wrote: >> Currently each message length in complete transfer is being >> checked for determining DMA mode and if any of the message length >> is less than FIFO length then non DMA mode is being used which >> will increase overhead. DMA can be used for any length and it >> should be determined with complete transfer length. Now, this >> patch introduces DMA threshold length and the transfer will be >> done in DMA mode if the total length is greater than this >> threshold length. >> >> Signed-off-by: Abhishek Sahu <absahu@codeaurora.org> >> --- >> drivers/i2c/busses/i2c-qup.c | 15 +++++++++------ >> 1 file changed, 9 insertions(+), 6 deletions(-) >> >> diff --git a/drivers/i2c/busses/i2c-qup.c >> b/drivers/i2c/busses/i2c-qup.c >> index 6227a5c..a91fc70 100644 >> --- a/drivers/i2c/busses/i2c-qup.c >> +++ b/drivers/i2c/busses/i2c-qup.c >> @@ -192,6 +192,8 @@ struct qup_i2c_dev { >> bool is_dma; >> /* To check if the current transfer is using DMA */ >> bool use_dma; >> + /* The threshold length above which DMA will be used */ >> + unsigned int dma_threshold; >> struct dma_pool *dpool; >> struct qup_i2c_tag start_tag; >> struct qup_i2c_bam brx; >> @@ -1294,7 +1296,8 @@ static int qup_i2c_xfer_v2(struct i2c_adapter >> *adap, >> int num) >> { >> struct qup_i2c_dev *qup = i2c_get_adapdata(adap); >> - int ret, len, idx = 0; >> + int ret, idx = 0; >> + unsigned int total_len = 0; >> >> qup->bus_err = 0; >> qup->qup_err = 0; >> @@ -1320,14 +1323,13 @@ static int qup_i2c_xfer_v2(struct i2c_adapter >> *adap, >> goto out; >> } >> >> - len = (msgs[idx].len > qup->out_fifo_sz) || >> - (msgs[idx].len > qup->in_fifo_sz); >> - >> - if (is_vmalloc_addr(msgs[idx].buf) || !len) >> + if (is_vmalloc_addr(msgs[idx].buf)) >> break; >> + >> + total_len += msgs[idx].len; >> } >> >> - if (idx == num) >> + if (idx == num && total_len > qup->dma_threshold) >> qup->use_dma = true; >> } >> >> @@ -1587,6 +1589,7 @@ static int qup_i2c_probe(struct platform_device >> *pdev) >> >> size = QUP_INPUT_FIFO_SIZE(io_mode); >> qup->in_fifo_sz = qup->in_blk_sz * (2 << size); >> + qup->dma_threshold = min(qup->out_fifo_sz, qup->in_fifo_sz); > > The patch is fine. small nit, you can avoid this global > dma_threshold. Instead > have it locally in qup_i2c_xfer_v2 itself. Thanks Sricharan. The idea for introducing global dma_threshold was to give option for controlling the behavior from one place. If someone wants to change the length above which dma will be used, then It can be controlled from once place in the probe function itself. Also, min(qup->out_fifo_sz, qup->in_fifo_sz) requires comparison and adding in qup_i2c_xfer_v2 will make this happen everytime. Regards, Abhishek
Tested on Centriq 2400 Reviewed-by: Austin Christ <austinwc@codeaurora.org> On 2/3/2018 12:58 AM, Abhishek Sahu wrote: > Currently each message length in complete transfer is being > checked for determining DMA mode and if any of the message length > is less than FIFO length then non DMA mode is being used which > will increase overhead. DMA can be used for any length and it > should be determined with complete transfer length. Now, this > patch introduces DMA threshold length and the transfer will be > done in DMA mode if the total length is greater than this > threshold length. > > Signed-off-by: Abhishek Sahu <absahu@codeaurora.org> > --- > drivers/i2c/busses/i2c-qup.c | 15 +++++++++------ > 1 file changed, 9 insertions(+), 6 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-qup.c b/drivers/i2c/busses/i2c-qup.c > index 6227a5c..a91fc70 100644 > --- a/drivers/i2c/busses/i2c-qup.c > +++ b/drivers/i2c/busses/i2c-qup.c > @@ -192,6 +192,8 @@ struct qup_i2c_dev { > bool is_dma; > /* To check if the current transfer is using DMA */ > bool use_dma; > + /* The threshold length above which DMA will be used */ > + unsigned int dma_threshold; > struct dma_pool *dpool; > struct qup_i2c_tag start_tag; > struct qup_i2c_bam brx; > @@ -1294,7 +1296,8 @@ static int qup_i2c_xfer_v2(struct i2c_adapter *adap, > int num) > { > struct qup_i2c_dev *qup = i2c_get_adapdata(adap); > - int ret, len, idx = 0; > + int ret, idx = 0; > + unsigned int total_len = 0; > > qup->bus_err = 0; > qup->qup_err = 0; > @@ -1320,14 +1323,13 @@ static int qup_i2c_xfer_v2(struct i2c_adapter *adap, > goto out; > } > > - len = (msgs[idx].len > qup->out_fifo_sz) || > - (msgs[idx].len > qup->in_fifo_sz); > - > - if (is_vmalloc_addr(msgs[idx].buf) || !len) > + if (is_vmalloc_addr(msgs[idx].buf)) > break; > + > + total_len += msgs[idx].len; > } > > - if (idx == num) > + if (idx == num && total_len > qup->dma_threshold) > qup->use_dma = true; > } > > @@ -1587,6 +1589,7 @@ static int qup_i2c_probe(struct platform_device *pdev) > > size = QUP_INPUT_FIFO_SIZE(io_mode); > qup->in_fifo_sz = qup->in_blk_sz * (2 << size); > + qup->dma_threshold = min(qup->out_fifo_sz, qup->in_fifo_sz); > > fs_div = ((src_clk_freq / clk_freq) / 2) - 3; > hs_div = 3; >
On Sat, Feb 03, 2018 at 01:28:12PM +0530, Abhishek Sahu wrote: > Currently each message length in complete transfer is being > checked for determining DMA mode and if any of the message length > is less than FIFO length then non DMA mode is being used which > will increase overhead. DMA can be used for any length and it > should be determined with complete transfer length. Now, this > patch introduces DMA threshold length and the transfer will be > done in DMA mode if the total length is greater than this > threshold length. > > Signed-off-by: Abhishek Sahu <absahu@codeaurora.org> > --- I agree with Sricharan's nit. Reviewed-by: Andy Gross <andy.gross@linaro.org>
diff --git a/drivers/i2c/busses/i2c-qup.c b/drivers/i2c/busses/i2c-qup.c index 6227a5c..a91fc70 100644 --- a/drivers/i2c/busses/i2c-qup.c +++ b/drivers/i2c/busses/i2c-qup.c @@ -192,6 +192,8 @@ struct qup_i2c_dev { bool is_dma; /* To check if the current transfer is using DMA */ bool use_dma; + /* The threshold length above which DMA will be used */ + unsigned int dma_threshold; struct dma_pool *dpool; struct qup_i2c_tag start_tag; struct qup_i2c_bam brx; @@ -1294,7 +1296,8 @@ static int qup_i2c_xfer_v2(struct i2c_adapter *adap, int num) { struct qup_i2c_dev *qup = i2c_get_adapdata(adap); - int ret, len, idx = 0; + int ret, idx = 0; + unsigned int total_len = 0; qup->bus_err = 0; qup->qup_err = 0; @@ -1320,14 +1323,13 @@ static int qup_i2c_xfer_v2(struct i2c_adapter *adap, goto out; } - len = (msgs[idx].len > qup->out_fifo_sz) || - (msgs[idx].len > qup->in_fifo_sz); - - if (is_vmalloc_addr(msgs[idx].buf) || !len) + if (is_vmalloc_addr(msgs[idx].buf)) break; + + total_len += msgs[idx].len; } - if (idx == num) + if (idx == num && total_len > qup->dma_threshold) qup->use_dma = true; } @@ -1587,6 +1589,7 @@ static int qup_i2c_probe(struct platform_device *pdev) size = QUP_INPUT_FIFO_SIZE(io_mode); qup->in_fifo_sz = qup->in_blk_sz * (2 << size); + qup->dma_threshold = min(qup->out_fifo_sz, qup->in_fifo_sz); fs_div = ((src_clk_freq / clk_freq) / 2) - 3; hs_div = 3;
Currently each message length in complete transfer is being checked for determining DMA mode and if any of the message length is less than FIFO length then non DMA mode is being used which will increase overhead. DMA can be used for any length and it should be determined with complete transfer length. Now, this patch introduces DMA threshold length and the transfer will be done in DMA mode if the total length is greater than this threshold length. Signed-off-by: Abhishek Sahu <absahu@codeaurora.org> --- drivers/i2c/busses/i2c-qup.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-)