Re: [PATCH] usb: chipidea: Configure DMA properties and ops from DT

From: Srinivas Kandagatla
Date: Mon Feb 22 2016 - 05:03:31 EST




On 22/02/16 05:32, Bjorn Andersson wrote:
On certain platforms (e.g. ARM64) the dma_ops needs to be explicitly set
to be able to do DMA allocations, so use the of_dma_configure() helper
to populate the dma properties and assign an appropriate dma_ops.

Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
---
drivers/usb/chipidea/core.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/usb/chipidea/core.c b/drivers/usb/chipidea/core.c
index 7404064b9bbc..047b9d4e67aa 100644
--- a/drivers/usb/chipidea/core.c
+++ b/drivers/usb/chipidea/core.c
@@ -62,6 +62,7 @@
#include <linux/usb/chipidea.h>
#include <linux/usb/of.h>
#include <linux/of.h>
+#include <linux/of_device.h>
#include <linux/phy.h>
#include <linux/regulator/consumer.h>
#include <linux/usb/ehci_def.h>
@@ -834,6 +835,9 @@ struct platform_device *ci_hdrc_add_device(struct device *dev,
pdev->dev.dma_parms = dev->dma_parms;
dma_set_coherent_mask(&pdev->dev, dev->coherent_dma_mask);

+ if (IS_ENABLED(CONFIG_OF) && dev->of_node)
+ of_dma_configure(&pdev->dev, dev->of_node);
+
Would we hit the same issue if we are on non Device tree platforms like ACPI or platform device style itself?


ret = platform_device_add_resources(pdev, res, nres);
if (ret)
goto err;


I think this is the side effect of commit 1dccb598df549d892b6450c261da54cdd7af44b4(arm64: simplify dma_get_ops)

None of the drivers call of_dma_configure() explicitly, which makes me feel that we are doing something wrong. TBH, this should be handled in more generic way rather than driver like this having an explicit call to of_dma_configure().


On the other hand, I think we could also solve the issue by using correct device(parent device) while allocating dma/dma-pool.


------------------------>cut<-----------------------------

diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c
index 6e53c24..0293ed5 100644
--- a/drivers/usb/chipidea/udc.c
+++ b/drivers/usb/chipidea/udc.c
@@ -1844,13 +1844,13 @@ static int udc_start(struct ci_hdrc *ci)
INIT_LIST_HEAD(&ci->gadget.ep_list);

/* alloc resources */
- ci->qh_pool = dma_pool_create("ci_hw_qh", dev,
+ ci->qh_pool = dma_pool_create("ci_hw_qh", dev->parent,
sizeof(struct ci_hw_qh),
64, CI_HDRC_PAGE_SIZE);
if (ci->qh_pool == NULL)
return -ENOMEM;

- ci->td_pool = dma_pool_create("ci_hw_td", dev,
+ ci->td_pool = dma_pool_create("ci_hw_td", dev->parent,
sizeof(struct ci_hw_td),
64, CI_HDRC_PAGE_SIZE);
if (ci->td_pool == NULL) {
------------------------>cut<-----------------------------


--srini