On 01/10/2017 11:05 AM, Sekhar Nori wrote:
> On Tuesday 10 January 2017 03:08 PM, Alexandre Bailon wrote:
>> On 01/09/2017 07:08 PM, Grygorii Strashko wrote:
>>>
>>>
>>> On 01/09/2017 10:06 AM, Alexandre Bailon wrote:
>>>> The da8xx has a cppi41 dma controller.
>>>> This is add the glue layer required to make it work on da8xx,
>>>> as well some changes in driver (e.g to manage clock).
>>>>
>>>> Signed-off-by: Alexandre Bailon <abailon@xxxxxxxxxxxx>
>>>> ---
>>>> drivers/dma/cppi41.c | 95 ++++++++++++++++++++++++++++++++++++++++++++++++++++
>>>> 1 file changed, 95 insertions(+)
>>>>
>>>> diff --git a/drivers/dma/cppi41.c b/drivers/dma/cppi41.c
>>>> index 939398e..4318e53 100644
>>>> --- a/drivers/dma/cppi41.c
>>>> +++ b/drivers/dma/cppi41.c
>>>> @@ -1,3 +1,4 @@
>>>> +#include <linux/clk.h>
>>>> #include <linux/delay.h>
>>>> #include <linux/dmaengine.h>
>>>> #include <linux/dma-mapping.h>
>>>> @@ -86,10 +87,19 @@
>>>>
>>>> #define USBSS_IRQ_PD_COMP (1 << 2)
>>>>
>>>> +/* USB DA8XX */
>>>> +#define DA8XX_INTR_SRC_MASKED 0x38
>>>> +#define DA8XX_END_OF_INTR 0x3c
>>>> +
>>>> +#define DA8XX_QMGR_PENDING_MASK (0xf << 24)
>>>> +
>>>> +
>>>> +
>>>> /* Packet Descriptor */
>>>> #define PD2_ZERO_LENGTH (1 << 19)
>>>>
>>>> #define AM335X_CPPI41 0
>>>> +#define DA8XX_CPPI41 1
>>>>
>>>> struct cppi41_channel {
>>>> struct dma_chan chan;
>>>> @@ -158,6 +168,9 @@ struct cppi41_dd {
>>>>
>>>> /* context for suspend/resume */
>>>> unsigned int dma_tdfdq;
>>>> +
>>>> + /* da8xx clock */
>>>> + struct clk *clk;
>>>> };
>>>>
>>>> static struct chan_queues am335x_usb_queues_tx[] = {
>>>> @@ -232,6 +245,20 @@ static const struct chan_queues am335x_usb_queues_rx[] = {
>>>> [29] = { .submit = 30, .complete = 155},
>>>> };
>>>>
>>>> +static const struct chan_queues da8xx_usb_queues_tx[] = {
>>>> + [0] = { .submit = 16, .complete = 24},
>>>> + [1] = { .submit = 18, .complete = 24},
>>>> + [2] = { .submit = 20, .complete = 24},
>>>> + [3] = { .submit = 22, .complete = 24},
>>>> +};
>>>> +
>>>> +static const struct chan_queues da8xx_usb_queues_rx[] = {
>>>> + [0] = { .submit = 1, .complete = 26},
>>>> + [1] = { .submit = 3, .complete = 26},
>>>> + [2] = { .submit = 5, .complete = 26},
>>>> + [3] = { .submit = 7, .complete = 26},
>>>> +};
>>>> +
>>>> struct cppi_glue_infos {
>>>> irqreturn_t (*isr)(int irq, void *data);
>>>> const struct chan_queues *queues_rx;
>>>> @@ -366,6 +393,26 @@ static irqreturn_t am335x_cppi41_irq(int irq, void *data)
>>>> return cppi41_irq(cdd);
>>>> }
>>>>
>>>> +static irqreturn_t da8xx_cppi41_irq(int irq, void *data)
>>>> +{
>>>> + struct cppi41_dd *cdd = data;
>>>> + u32 status;
>>>> + u32 usbss_status;
>>>> +
>>>> + status = cppi_readl(cdd->qmgr_mem + QMGR_PEND(0));
>>>> + if (status & DA8XX_QMGR_PENDING_MASK)
>>>> + cppi41_irq(cdd);
>>>> + else
>>>> + return IRQ_NONE;
>>>> +
>>>> + /* Re-assert IRQ if there no usb core interrupts pending */
>>>> + usbss_status = cppi_readl(cdd->usbss_mem + DA8XX_INTR_SRC_MASKED);
>>>> + if (!usbss_status)
>>>> + cppi_writel(0, cdd->usbss_mem + DA8XX_END_OF_INTR);
>>>> +
>>>> + return IRQ_HANDLED;
>>>> +}
>>>> +
>>>> static dma_cookie_t cppi41_tx_submit(struct dma_async_tx_descriptor *tx)
>>>> {
>>>> dma_cookie_t cookie;
>>>> @@ -972,8 +1019,19 @@ static const struct cppi_glue_infos am335x_usb_infos = {
>>>> .platform = AM335X_CPPI41,
>>>> };
>>>>
>>>> +static const struct cppi_glue_infos da8xx_usb_infos = {
>>>> + .isr = da8xx_cppi41_irq,
>>>> + .queues_rx = da8xx_usb_queues_rx,
>>>> + .queues_tx = da8xx_usb_queues_tx,
>>>> + .td_queue = { .submit = 31, .complete = 0 },
>>>> + .first_completion_queue = 24,
>>>> + .qmgr_num_pend = 2,
>>>> + .platform = DA8XX_CPPI41,
>>>> +};
>>>> +
>>>> static const struct of_device_id cppi41_dma_ids[] = {
>>>> { .compatible = "ti,am3359-cppi41", .data = &am335x_usb_infos},
>>>> + { .compatible = "ti,da8xx-cppi41", .data = &da8xx_usb_infos},
>>>> {},
>>>> };
>>>> MODULE_DEVICE_TABLE(of, cppi41_dma_ids);
>>>> @@ -995,6 +1053,13 @@ static int is_am335x_cppi41(struct device *dev)
>>>> return cdd->platform == AM335X_CPPI41;
>>>> }
>>>>
>>>> +static int is_da8xx_cppi41(struct device *dev)
>>>> +{
>>>> + struct cppi41_dd *cdd = dev_get_drvdata(dev);
>>>> +
>>>> + return cdd->platform == DA8XX_CPPI41;
>>>> +}
>>>> +
>>>> #define CPPI41_DMA_BUSWIDTHS (BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) | \
>>>> BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | \
>>>> BIT(DMA_SLAVE_BUSWIDTH_3_BYTES) | \
>>>> @@ -1058,6 +1123,21 @@ static int cppi41_dma_probe(struct platform_device *pdev)
>>>> cdd->first_completion_queue = glue_info->first_completion_queue;
>>>> cdd->platform = glue_info->platform;
>>>>
>>>> + if (is_da8xx_cppi41(dev)) {
>>>> + cdd->clk = devm_clk_get(&pdev->dev, "usb20");
>>>> + ret = PTR_ERR_OR_ZERO(cdd->clk);
>>>> + if (ret) {
>>>> + dev_err(&pdev->dev, "failed to get clock\n");
>>>> + goto err_clk_en;
>>>> + }
>>>> +
>>>> + ret = clk_prepare_enable(cdd->clk);
>>>> + if (ret) {
>>>> + dev_err(dev, "failed to enable clock\n");
>>>> + goto err_clk_en;
>>>> + }
>>>> + }
>>>
>>> if this is functional clock then why not to use ./arch/arm/mach-davinci/pm_domain.c ?
>>> wouldn't it work for use if you will just rename "usb20" -> "fck" -
>>> so PM runtime should manage this clock for you?
>> As is, I don't think it will work.
>> The usb20 is shared by the cppi41 and the usb otg.
>> So, if we rename "usb20" to "fck", clk_get() won't be able to find the
>> clock.
>> But may be adding "usb20" to "con_ids" in
>> arch/arm/mach-davinci/pm_domain.c could work.
>> But I think it will require some changes in da8xx musb driver.
>> I will take look.
>
> On DA8xx, CPPI 4.1 DMAengine is not an independent system resource, but
> embedded within the USB 2.0 controller. So, I think all that is needed
> is for MUSB DA8xx glue to trigger probe of CPPI 4.1 dmaengine driver
> when it is ready. I am not sure all this DA850-specific clock handling
> is really necessary.
Actually, we have a circular dependency.
USB core tries to get DMA channels during the probe, which fails because
CPPI 4.1 driver is not ready.
But it will never be ready because the USB clock must be enabled before
DMA driver probe, what will not happen because USB driver have disabled
the clock when probe failed.
Someone in the office suggested me to use the component API,
that could help me to probe the DMA from the USB probe.
Another way to workaround the dependency would be to do defer the
function calls that access to hardware to avoid to control clock from
DMA driver.
>
> Even in DT, the CPPI 4.1 node should be a child node of USB 2.0 node.
I agree, it should a child but it would require some changes in CPPI 4.1
driver. But except to have a better hardware description, I don't see
any benefit to do it.
>
> Thanks,
> sekhar
>
Thanks,
Alexandre
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