Add support for dma-channel-mask so that only the specified channels
are used. This helps to reserve some channels for the firmware.
This was initially achieved by limiting the channel number to 31 in
the driver and adjusting the register address to skip channel0 which
was reserved for a firmware. Now, with this change, the driver can
align more to the actual hardware which has 32 channels.
Signed-off-by: Akhil R <[email protected]>
---
drivers/dma/tegra186-gpc-dma.c | 37 +++++++++++++++++++++++++++-------
1 file changed, 30 insertions(+), 7 deletions(-)
diff --git a/drivers/dma/tegra186-gpc-dma.c b/drivers/dma/tegra186-gpc-dma.c
index fa9bda4a2bc6..1d1180db6d4e 100644
--- a/drivers/dma/tegra186-gpc-dma.c
+++ b/drivers/dma/tegra186-gpc-dma.c
@@ -161,7 +161,10 @@
#define TEGRA_GPCDMA_BURST_COMPLETION_TIMEOUT 5000 /* 5 msec */
/* Channel base address offset from GPCDMA base address */
-#define TEGRA_GPCDMA_CHANNEL_BASE_ADD_OFFSET 0x20000
+#define TEGRA_GPCDMA_CHANNEL_BASE_ADDR_OFFSET 0x10000
+
+/* Default channel mask reserving channel0 */
+#define TEGRA_GPCDMA_DEFAULT_CHANNEL_MASK 0xfffffffe
struct tegra_dma;
struct tegra_dma_channel;
@@ -246,6 +249,7 @@ struct tegra_dma {
const struct tegra_dma_chip_data *chip_data;
unsigned long sid_m2d_reserved;
unsigned long sid_d2m_reserved;
+ u32 chan_mask;
void __iomem *base_addr;
struct device *dev;
struct dma_device dma_dev;
@@ -1288,7 +1292,7 @@ static struct dma_chan *tegra_dma_of_xlate(struct of_phandle_args *dma_spec,
}
static const struct tegra_dma_chip_data tegra186_dma_chip_data = {
- .nr_channels = 31,
+ .nr_channels = 32,
.channel_reg_size = SZ_64K,
.max_dma_count = SZ_1G,
.hw_support_pause = false,
@@ -1296,7 +1300,7 @@ static const struct tegra_dma_chip_data tegra186_dma_chip_data = {
};
static const struct tegra_dma_chip_data tegra194_dma_chip_data = {
- .nr_channels = 31,
+ .nr_channels = 32,
.channel_reg_size = SZ_64K,
.max_dma_count = SZ_1G,
.hw_support_pause = true,
@@ -1304,7 +1308,7 @@ static const struct tegra_dma_chip_data tegra194_dma_chip_data = {
};
static const struct tegra_dma_chip_data tegra234_dma_chip_data = {
- .nr_channels = 31,
+ .nr_channels = 32,
.channel_reg_size = SZ_64K,
.max_dma_count = SZ_1G,
.hw_support_pause = true,
@@ -1380,15 +1384,28 @@ static int tegra_dma_probe(struct platform_device *pdev)
}
stream_id = iommu_spec->ids[0] & 0xffff;
+ ret = device_property_read_u32(&pdev->dev, "dma-channel-mask",
+ &tdma->chan_mask);
+ if (ret) {
+ dev_warn(&pdev->dev,
+ "Missing dma-channel-mask property, using default channel mask %#x\n",
+ TEGRA_GPCDMA_DEFAULT_CHANNEL_MASK);
+ tdma->chan_mask = TEGRA_GPCDMA_DEFAULT_CHANNEL_MASK;
+ }
+
INIT_LIST_HEAD(&tdma->dma_dev.channels);
for (i = 0; i < cdata->nr_channels; i++) {
struct tegra_dma_channel *tdc = &tdma->channels[i];
+ /* Check for channel mask */
+ if (!(tdma->chan_mask & BIT(i)))
+ continue;
+
tdc->irq = platform_get_irq(pdev, i);
if (tdc->irq < 0)
return tdc->irq;
- tdc->chan_base_offset = TEGRA_GPCDMA_CHANNEL_BASE_ADD_OFFSET +
+ tdc->chan_base_offset = TEGRA_GPCDMA_CHANNEL_BASE_ADDR_OFFSET +
i * cdata->channel_reg_size;
snprintf(tdc->name, sizeof(tdc->name), "gpcdma.%d", i);
tdc->tdma = tdma;
@@ -1449,8 +1466,8 @@ static int tegra_dma_probe(struct platform_device *pdev)
return ret;
}
- dev_info(&pdev->dev, "GPC DMA driver register %d channels\n",
- cdata->nr_channels);
+ dev_info(&pdev->dev, "GPC DMA driver register %lu channels\n",
+ hweight_long(tdma->chan_mask));
return 0;
}
@@ -1473,6 +1490,9 @@ static int __maybe_unused tegra_dma_pm_suspend(struct device *dev)
for (i = 0; i < tdma->chip_data->nr_channels; i++) {
struct tegra_dma_channel *tdc = &tdma->channels[i];
+ if (!(tdma->chan_mask & BIT(i)))
+ continue;
+
if (tdc->dma_desc) {
dev_err(tdma->dev, "channel %u busy\n", i);
return -EBUSY;
@@ -1492,6 +1512,9 @@ static int __maybe_unused tegra_dma_pm_resume(struct device *dev)
for (i = 0; i < tdma->chip_data->nr_channels; i++) {
struct tegra_dma_channel *tdc = &tdma->channels[i];
+ if (!(tdma->chan_mask & BIT(i)))
+ continue;
+
tegra_dma_program_sid(tdc, tdc->stream_id);
}
--
2.17.1
On 19/09/2022 12:25, Akhil R wrote:
> Add support for dma-channel-mask so that only the specified channels
> are used. This helps to reserve some channels for the firmware.
>
> This was initially achieved by limiting the channel number to 31 in
> the driver and adjusting the register address to skip channel0 which
> was reserved for a firmware. Now, with this change, the driver can
> align more to the actual hardware which has 32 channels.
>
> Signed-off-by: Akhil R <[email protected]>
> ---
> drivers/dma/tegra186-gpc-dma.c | 37 +++++++++++++++++++++++++++-------
> 1 file changed, 30 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/dma/tegra186-gpc-dma.c b/drivers/dma/tegra186-gpc-dma.c
> index fa9bda4a2bc6..1d1180db6d4e 100644
> --- a/drivers/dma/tegra186-gpc-dma.c
> +++ b/drivers/dma/tegra186-gpc-dma.c
> @@ -161,7 +161,10 @@
> #define TEGRA_GPCDMA_BURST_COMPLETION_TIMEOUT 5000 /* 5 msec */
>
> /* Channel base address offset from GPCDMA base address */
> -#define TEGRA_GPCDMA_CHANNEL_BASE_ADD_OFFSET 0x20000
> +#define TEGRA_GPCDMA_CHANNEL_BASE_ADDR_OFFSET 0x10000
Why did this value change? There is no mention in the commit message. If
this was incorrect before, then this needs to be a separate patch and
tagged with the appropriate fixes tag so that this can be picked up for
stable.
Thanks
Jon
--
nvpublic
On 23/09/2022 11:17, Akhil R wrote:
>> On 19/09/2022 12:25, Akhil R wrote:
>>> Add support for dma-channel-mask so that only the specified channels
>>> are used. This helps to reserve some channels for the firmware.
>>>
>>> This was initially achieved by limiting the channel number to 31 in
>>> the driver and adjusting the register address to skip channel0 which
>>> was reserved for a firmware. Now, with this change, the driver can
>>> align more to the actual hardware which has 32 channels.
>>>
>>> Signed-off-by: Akhil R <[email protected]>
>>> ---
>>> drivers/dma/tegra186-gpc-dma.c | 37 +++++++++++++++++++++++++++-------
>>> 1 file changed, 30 insertions(+), 7 deletions(-)
>>>
>>> diff --git a/drivers/dma/tegra186-gpc-dma.c b/drivers/dma/tegra186-gpc-
>> dma.c
>>> index fa9bda4a2bc6..1d1180db6d4e 100644
>>> --- a/drivers/dma/tegra186-gpc-dma.c
>>> +++ b/drivers/dma/tegra186-gpc-dma.c
>>> @@ -161,7 +161,10 @@
>>> #define TEGRA_GPCDMA_BURST_COMPLETION_TIMEOUT 5000 /* 5
>> msec */
>>>
>>> /* Channel base address offset from GPCDMA base address */
>>> -#define TEGRA_GPCDMA_CHANNEL_BASE_ADD_OFFSET 0x20000
>>> +#define TEGRA_GPCDMA_CHANNEL_BASE_ADDR_OFFSET 0x10000
>>
>> Why did this value change? There is no mention in the commit message. If
>> this was incorrect before, then this needs to be a separate patch and
>> tagged with the appropriate fixes tag so that this can be picked up for
>> stable.
> This is mentioned in the commit message.
>
> "... and adjusting the register address to skip channel0 ..."
>
> Probably it is not very clear that it directs to this change. Shall I update the
> commit message to have a clearer context?
Ah OK. I was wondering how this worked with 'channel_reg_size' but
looking closer I see channel_reg_size is always SZ_64K. I wonder why we
even bother having this parameter and don't use SZ_64K directly?
Anyway, for now this is fine.
Jon
--
nvpublic
> On 19/09/2022 12:25, Akhil R wrote:
> > Add support for dma-channel-mask so that only the specified channels
> > are used. This helps to reserve some channels for the firmware.
> >
> > This was initially achieved by limiting the channel number to 31 in
> > the driver and adjusting the register address to skip channel0 which
> > was reserved for a firmware. Now, with this change, the driver can
> > align more to the actual hardware which has 32 channels.
> >
> > Signed-off-by: Akhil R <[email protected]>
> > ---
> > drivers/dma/tegra186-gpc-dma.c | 37 +++++++++++++++++++++++++++-------
> > 1 file changed, 30 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/dma/tegra186-gpc-dma.c b/drivers/dma/tegra186-gpc-
> dma.c
> > index fa9bda4a2bc6..1d1180db6d4e 100644
> > --- a/drivers/dma/tegra186-gpc-dma.c
> > +++ b/drivers/dma/tegra186-gpc-dma.c
> > @@ -161,7 +161,10 @@
> > #define TEGRA_GPCDMA_BURST_COMPLETION_TIMEOUT 5000 /* 5
> msec */
> >
> > /* Channel base address offset from GPCDMA base address */
> > -#define TEGRA_GPCDMA_CHANNEL_BASE_ADD_OFFSET 0x20000
> > +#define TEGRA_GPCDMA_CHANNEL_BASE_ADDR_OFFSET 0x10000
>
> Why did this value change? There is no mention in the commit message. If
> this was incorrect before, then this needs to be a separate patch and
> tagged with the appropriate fixes tag so that this can be picked up for
> stable.
This is mentioned in the commit message.
"... and adjusting the register address to skip channel0 ..."
Probably it is not very clear that it directs to this change. Shall I update the
commit message to have a clearer context?
Regards,
Akhil
On 19/09/2022 12:25, Akhil R wrote:
> Add support for dma-channel-mask so that only the specified channels
> are used. This helps to reserve some channels for the firmware.
>
> This was initially achieved by limiting the channel number to 31 in
> the driver and adjusting the register address to skip channel0 which
> was reserved for a firmware. Now, with this change, the driver can
> align more to the actual hardware which has 32 channels.
>
> Signed-off-by: Akhil R <[email protected]>
> ---
> drivers/dma/tegra186-gpc-dma.c | 37 +++++++++++++++++++++++++++-------
> 1 file changed, 30 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/dma/tegra186-gpc-dma.c b/drivers/dma/tegra186-gpc-dma.c
> index fa9bda4a2bc6..1d1180db6d4e 100644
> --- a/drivers/dma/tegra186-gpc-dma.c
> +++ b/drivers/dma/tegra186-gpc-dma.c
> @@ -161,7 +161,10 @@
> #define TEGRA_GPCDMA_BURST_COMPLETION_TIMEOUT 5000 /* 5 msec */
>
> /* Channel base address offset from GPCDMA base address */
> -#define TEGRA_GPCDMA_CHANNEL_BASE_ADD_OFFSET 0x20000
> +#define TEGRA_GPCDMA_CHANNEL_BASE_ADDR_OFFSET 0x10000
> +
> +/* Default channel mask reserving channel0 */
> +#define TEGRA_GPCDMA_DEFAULT_CHANNEL_MASK 0xfffffffe
>
> struct tegra_dma;
> struct tegra_dma_channel;
> @@ -246,6 +249,7 @@ struct tegra_dma {
> const struct tegra_dma_chip_data *chip_data;
> unsigned long sid_m2d_reserved;
> unsigned long sid_d2m_reserved;
> + u32 chan_mask;
> void __iomem *base_addr;
> struct device *dev;
> struct dma_device dma_dev;
> @@ -1288,7 +1292,7 @@ static struct dma_chan *tegra_dma_of_xlate(struct of_phandle_args *dma_spec,
> }
>
> static const struct tegra_dma_chip_data tegra186_dma_chip_data = {
> - .nr_channels = 31,
> + .nr_channels = 32,
> .channel_reg_size = SZ_64K,
> .max_dma_count = SZ_1G,
> .hw_support_pause = false,
> @@ -1296,7 +1300,7 @@ static const struct tegra_dma_chip_data tegra186_dma_chip_data = {
> };
>
> static const struct tegra_dma_chip_data tegra194_dma_chip_data = {
> - .nr_channels = 31,
> + .nr_channels = 32,
> .channel_reg_size = SZ_64K,
> .max_dma_count = SZ_1G,
> .hw_support_pause = true,
> @@ -1304,7 +1308,7 @@ static const struct tegra_dma_chip_data tegra194_dma_chip_data = {
> };
>
> static const struct tegra_dma_chip_data tegra234_dma_chip_data = {
> - .nr_channels = 31,
> + .nr_channels = 32,
> .channel_reg_size = SZ_64K,
> .max_dma_count = SZ_1G,
> .hw_support_pause = true,
> @@ -1380,15 +1384,28 @@ static int tegra_dma_probe(struct platform_device *pdev)
> }
> stream_id = iommu_spec->ids[0] & 0xffff;
>
> + ret = device_property_read_u32(&pdev->dev, "dma-channel-mask",
> + &tdma->chan_mask);
> + if (ret) {
> + dev_warn(&pdev->dev,
> + "Missing dma-channel-mask property, using default channel mask %#x\n",
> + TEGRA_GPCDMA_DEFAULT_CHANNEL_MASK);
> + tdma->chan_mask = TEGRA_GPCDMA_DEFAULT_CHANNEL_MASK;
> + }
> +
> INIT_LIST_HEAD(&tdma->dma_dev.channels);
> for (i = 0; i < cdata->nr_channels; i++) {
> struct tegra_dma_channel *tdc = &tdma->channels[i];
>
> + /* Check for channel mask */
> + if (!(tdma->chan_mask & BIT(i)))
> + continue;
> +
> tdc->irq = platform_get_irq(pdev, i);
> if (tdc->irq < 0)
> return tdc->irq;
>
> - tdc->chan_base_offset = TEGRA_GPCDMA_CHANNEL_BASE_ADD_OFFSET +
> + tdc->chan_base_offset = TEGRA_GPCDMA_CHANNEL_BASE_ADDR_OFFSET +
> i * cdata->channel_reg_size;
> snprintf(tdc->name, sizeof(tdc->name), "gpcdma.%d", i);
> tdc->tdma = tdma;
> @@ -1449,8 +1466,8 @@ static int tegra_dma_probe(struct platform_device *pdev)
> return ret;
> }
>
> - dev_info(&pdev->dev, "GPC DMA driver register %d channels\n",
> - cdata->nr_channels);
> + dev_info(&pdev->dev, "GPC DMA driver register %lu channels\n",
> + hweight_long(tdma->chan_mask));
>
> return 0;
> }
> @@ -1473,6 +1490,9 @@ static int __maybe_unused tegra_dma_pm_suspend(struct device *dev)
> for (i = 0; i < tdma->chip_data->nr_channels; i++) {
> struct tegra_dma_channel *tdc = &tdma->channels[i];
>
> + if (!(tdma->chan_mask & BIT(i)))
> + continue;
> +
> if (tdc->dma_desc) {
> dev_err(tdma->dev, "channel %u busy\n", i);
> return -EBUSY;
> @@ -1492,6 +1512,9 @@ static int __maybe_unused tegra_dma_pm_resume(struct device *dev)
> for (i = 0; i < tdma->chip_data->nr_channels; i++) {
> struct tegra_dma_channel *tdc = &tdma->channels[i];
>
> + if (!(tdma->chan_mask & BIT(i)))
> + continue;
> +
> tegra_dma_program_sid(tdc, tdc->stream_id);
> }
>
Reviewed-by: Jon Hunter <[email protected]>
Thanks!
Jon
--
nvpublic
> On 23/09/2022 11:17, Akhil R wrote:
> >> On 19/09/2022 12:25, Akhil R wrote:
> >>> Add support for dma-channel-mask so that only the specified channels
> >>> are used. This helps to reserve some channels for the firmware.
> >>>
> >>> This was initially achieved by limiting the channel number to 31 in
> >>> the driver and adjusting the register address to skip channel0 which
> >>> was reserved for a firmware. Now, with this change, the driver can
> >>> align more to the actual hardware which has 32 channels.
> >>>
> >>> Signed-off-by: Akhil R <[email protected]>
> >>> ---
> >>> drivers/dma/tegra186-gpc-dma.c | 37 +++++++++++++++++++++++++++---
> ----
> >>> 1 file changed, 30 insertions(+), 7 deletions(-)
> >>>
> >>> diff --git a/drivers/dma/tegra186-gpc-dma.c b/drivers/dma/tegra186-gpc-
> >> dma.c
> >>> index fa9bda4a2bc6..1d1180db6d4e 100644
> >>> --- a/drivers/dma/tegra186-gpc-dma.c
> >>> +++ b/drivers/dma/tegra186-gpc-dma.c
> >>> @@ -161,7 +161,10 @@
> >>> #define TEGRA_GPCDMA_BURST_COMPLETION_TIMEOUT 5000 /* 5
> >> msec */
> >>>
> >>> /* Channel base address offset from GPCDMA base address */
> >>> -#define TEGRA_GPCDMA_CHANNEL_BASE_ADD_OFFSET 0x20000
> >>> +#define TEGRA_GPCDMA_CHANNEL_BASE_ADDR_OFFSET 0x10000
> >>
> >> Why did this value change? There is no mention in the commit message. If
> >> this was incorrect before, then this needs to be a separate patch and
> >> tagged with the appropriate fixes tag so that this can be picked up for
> >> stable.
> > This is mentioned in the commit message.
> >
> > "... and adjusting the register address to skip channel0 ..."
> >
> > Probably it is not very clear that it directs to this change. Shall I update the
> > commit message to have a clearer context?
>
> Ah OK. I was wondering how this worked with 'channel_reg_size' but
> looking closer I see channel_reg_size is always SZ_64K. I wonder why we
> even bother having this parameter and don't use SZ_64K directly?
There is an offset from the base address which the per channel registers start.
Although this offset value happens to match with the channel_reg_size, this is
not actually the per channel register size.
>
> Anyway, for now this is fine.
>
Thanks for the review.
Regards,
Akhil
On 23/09/2022 12:09, Akhil R wrote:
...
>> Ah OK. I was wondering how this worked with 'channel_reg_size' but
>> looking closer I see channel_reg_size is always SZ_64K. I wonder why we
>> even bother having this parameter and don't use SZ_64K directly?
> There is an offset from the base address which the per channel registers start.
> Although this offset value happens to match with the channel_reg_size, this is
> not actually the per channel register size.
Yes I see that, but I mean why do we even bother having this
channel_reg_size parameter? Does not look like we need this (currently).
All we need is ...
tdc->chan_base_offset = TEGRA_GPCDMA_CHANNEL_BASE_ADDR_OFFSET +
(i * SZ_64K);
Jon
--
nvpublic
> >> Ah OK. I was wondering how this worked with 'channel_reg_size' but
> >> looking closer I see channel_reg_size is always SZ_64K. I wonder why we
> >> even bother having this parameter and don't use SZ_64K directly?
> > There is an offset from the base address which the per channel registers start.
> > Although this offset value happens to match with the channel_reg_size, this is
> > not actually the per channel register size.
>
> Yes I see that, but I mean why do we even bother having this
> channel_reg_size parameter? Does not look like we need this (currently).
> All we need is ...
>
> tdc->chan_base_offset = TEGRA_GPCDMA_CHANNEL_BASE_ADDR_OFFSET +
> (i * SZ_64K);
>
Ah. Ok. Got it now. Would add this as an improvement in another patch.
Thanks,
Akhil