Re: [PATCH 0/4] usb: musb: tusb6010_omap: Convert to DMAengine

From: Peter Ujfalusi
Date: Fri May 05 2017 - 03:28:38 EST

On 2017-05-04 17:31, Tony Lindgren wrote:
* Peter Ujfalusi <peter.ujfalusi@xxxxxx> [170503 04:00]:

With port_window support implemented in DMAengine and the sDMA DMAengine driver,
the tusb6010_omap driver can be converted away from the custom legacy omap-dma
API to generic DMAengine.

The first two patch is to prepare the tusb6010_omap driver for the conversion.
The third one adds the needed entries for the dma_slave_map so we can request
the DMA channels. This can be reverted when the stack is converted to DT.

The last patch does the main work to move the driver to DMAengine API.

I have tested the set on top of next-20170503 on Nokia n810 with nfsroot using
CDC Ethernet (g_cdc) and copying files with scp to/form my host.

Thanks for doing this! For this series:

Acked-by: Tony Lindgren <tony@xxxxxxxxxxx>

To force that the DMA is actually used I have:
diff --git a/drivers/usb/musb/tusb6010_omap.c b/drivers/usb/musb/tusb6010_omap.c
index 05aefcad40b5..a5fc2a6bdad3 100644
--- a/drivers/usb/musb/tusb6010_omap.c
+++ b/drivers/usb/musb/tusb6010_omap.c
@@ -216,8 +216,8 @@ static int tusb_omap_dma_program(struct dma_channel *channel, u16 packet_sz,
* use a timer for the callback, but it is unsafe as the XFR_SIZE
* register is corrupt, and we won't know if the DMA worked.
- if (dma_addr & 0x2)
- return false;
+// if (dma_addr & 0x2)
+// return false;

* Because of HW issue #10, it seems like mixing sync DMA and async

Since this condition will almost all the time was true - effectively disabling
the DMA use.

Yeah this really should have the transfers aligned to 32-bit like
the production kernel did. For reference, the following should do
the trick but of course would have to be done conditionally.



8< ----------------------
diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c
--- a/drivers/usb/musb/musb_gadget.c
+++ b/drivers/usb/musb/musb_gadget.c
@@ -2153,6 +2153,7 @@ __acquires(musb->lock)
musb->g.a_alt_hnp_support = 0;
musb->g.a_hnp_support = 0;
musb->g.quirk_zlp_not_supp = 1;
+ musb->g.quirk_avoids_skb_reserve = 1;

note for myself: this only works with g_ncm. I was using g_cdc, switched to g_ether, then to g_ncm.
However... If I revert this series and add this line, the ethernet will not work at all, I can not ping the n810 and it will not get the nfsroot either (next-20170503).

only f_ncm.c does:
ncm->port.no_skb_reserve =

/* Normal reset, as B-Device;
* or else after HNP, as A-Device

- Péter