From: Peter Ujfalusi <peter.ujfalusi@ti.com>
To: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: <vkoul@kernel.org>, <dan.j.williams@intel.com>,
<dmaengine@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<tony@atomide.com>, <linux-omap@vger.kernel.org>,
<rmk+kernel@armlinux.org.uk>,
Felipe Balbi <felipe.balbi@linux.intel.com>
Subject: Re: [PATCH] dmaengine: ti: omap-dma: Configure LCH_TYPE for OMAP1
Date: Fri, 23 Nov 2018 13:45:46 +0200 [thread overview]
Message-ID: <cb1355b5-0d2e-1f83-5ea1-7615350ca0ec@ti.com> (raw)
In-Reply-To: <20181122220114.GB11423@darkstar.musicnaut.iki.fi>
On 23/11/2018 0.01, Aaro Koskinen wrote:
> Hi,
>
> On Thu, Nov 22, 2018 at 10:31:31AM +0200, Peter Ujfalusi wrote:
>> On 20/11/2018 23.04, Aaro Koskinen wrote:
>>> On Tue, Nov 20, 2018 at 09:28:37AM +0200, Peter Ujfalusi wrote:
>>>> On 19/11/2018 20.46, Aaro Koskinen wrote:
>>>>> On Mon, Nov 19, 2018 at 12:40:40PM +0200, Peter Ujfalusi wrote:
>>>>>> When the channel is configured for slave operation the LCH_TYPE needs to be
>>>>>> set to LCh-P. For memcpy channels the LCH_TYPE must be set to LCh-2D.
>>>>>>
>>>>>> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
>>>>>
>>>>> I don't have the documentation, but based on what omap_udc driver (still
>>>>> using the legacy OMAP DMA API) does this seems to be correct.
>>>>
>>>> They are hard to fine, true. From the omap1710 TRM:
>>>>
>>>> Logical channel types (LCh types) supported are:
>>>> - LCh-2D for nonsynchronized transfers (memory transfers, 1D and 2D)
>>>> - LCh-P for synchronized transfers (mostly peripheral transfers)
>>>> - LCh-PD similar to LCh-P but runs on a dedicated physical channel
>>>> - LCh-G for graphical transfers/operations
>>>> - LCh-D for display transfers
>>>
>>> (I found a public document "OMAP5912 Multimedia Processor Direct
>>> Memory Access (DMA) Support Reference Guide", documenting these; easy
>>> to confuse with "OMAP5910 Dual-Core Processor System DMA Controller
>>> Reference Guide".)
>>>
>>>> Looking at other part it looks like hat LCH-2D channel mode can happily
>>>> service a peripheral. LCH-P supports the same features as LCH-2D, but it
>>>> lacks support for Single/Double-indexed addressing mode on the
>>>> peripheral port side.
>>>>
>>>> So, this patch might not be needed at all. Can you test the omap_udc
>>>> with s/OMAP_DMA_LCH_P/OMAP_DMA_LCH_2D
>>>>
>>>> If USB works, then we can just drop this patch.
>>>
>>> Unfortunately omap_udc does not seem to work at all anymore with DMA on
>>> my 770 setup. :-(
>>>
>>> I had switched to PIO mode in 2015 since the WARNs about legacy DMA
>>> API were too annoying and flooding the console. And now that I tried
>>> using DMA again with g_ether, it doesn't work anymore. The device get's
>>> recognized on host side, but no traffic goes through. Switching back to
>>> PIO makes it to work again.
>>
>> After some tinkering I got omap_udc working with DMA (not DMAengine,
>> yet) on 770 - using nfsroot. Configuring the channels to OMAP_DMA_LCH_2D
>> works as expected.
>
> Would be interesting to know how you got it working with DMA. Which
> gadget driver were you using?
>
> I bisected my issue, and got:
>
> commit 387f869d2579e379ee343f5493dcd360be60f5c6 (refs/bisect/bad)
> Author: Felipe Balbi <felipe.balbi@linux.intel.com>
> Date: Wed Mar 22 13:25:18 2017 +0200
>
> usb: gadget: u_ether: conditionally align transfer size
I just:
commit 0d61d79625202c1c4fcf07fb960e27984a3657a3
Author: Peter Ujfalusi <peter.ujfalusi@ti.com>
Date: Thu Nov 22 10:36:55 2018 +0200
usb: gadget: omap_udc: HACK: Make RX dma work
partial packets do work...
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
diff --git a/drivers/usb/gadget/udc/omap_udc.c b/drivers/usb/gadget/udc/omap_udc.c
index 94128eb69d97..0748c3841a25 100644
--- a/drivers/usb/gadget/udc/omap_udc.c
+++ b/drivers/usb/gadget/udc/omap_udc.c
@@ -886,14 +886,14 @@ omap_ep_queue(struct usb_ep *_ep, struct usb_request *_req, gfp_t gfp_flags)
/* this isn't bogus, but OMAP DMA isn't the only hardware to
* have a hard time with partial packet reads... reject it.
+ * Wait a minute, it does work :o
*/
if (use_dma
&& ep->has_dma
&& ep->bEndpointAddress != 0
&& (ep->bEndpointAddress & USB_DIR_IN) == 0
&& (req->req.length % ep->ep.maxpacket) != 0) {
- DBG("%s, no partial packet OUT reads\n", __func__);
- return -EMSGSIZE;
+ DBG("%s, partial packet OUT, might not work?\n", __func__);
}
udc = ep->udc;
> With that reverted, the DMA works OK (and I can also now confirm that
> OMAP_DMA_LCH_2D works). I haven't yet checked if we actually need that
> quirk in OMAP UDC,
The omap_udc driver is a bit of a mess, need to check it myself, but for
now we can just set the quirk_ep_out_aligned_size and investigate later.
> or if this is related to RMK's findings of potential
> bugs in the driver. Anyway, there is clearly yet another regression.
I'll check Russell's mail.
>
> A.
>
- Péter
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
next prev parent reply other threads:[~2018-11-23 11:44 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-19 10:40 [PATCH] dmaengine: ti: omap-dma: Configure LCH_TYPE for OMAP1 Peter Ujfalusi
2018-11-19 18:46 ` Aaro Koskinen
2018-11-20 7:28 ` Peter Ujfalusi
2018-11-20 21:04 ` Aaro Koskinen
2018-11-22 8:31 ` Peter Ujfalusi
2018-11-22 22:01 ` Aaro Koskinen
2018-11-23 11:45 ` Peter Ujfalusi [this message]
2018-11-24 0:17 ` Aaro Koskinen
2018-11-24 17:48 ` Russell King - ARM Linux
2018-11-24 19:06 ` Aaro Koskinen
2018-11-24 19:29 ` Russell King - ARM Linux
2018-11-22 10:29 ` Russell King - ARM Linux
2018-11-22 15:12 ` Russell King - ARM Linux
2018-11-22 22:24 ` Aaro Koskinen
2018-11-23 0:25 ` Russell King - ARM Linux
2018-11-23 1:23 ` Aaro Koskinen
2018-11-23 11:54 ` Peter Ujfalusi
2018-11-23 12:35 ` Peter Ujfalusi
2018-11-23 15:43 ` Russell King - ARM Linux
2018-11-23 16:16 ` Russell King - ARM Linux
2018-11-23 23:27 ` Russell King - ARM Linux
2018-11-23 18:52 ` Aaro Koskinen
2018-11-24 20:09 ` Russell King - ARM Linux
2018-11-25 1:07 ` Tony Lindgren
2018-11-25 1:11 ` Tony Lindgren
2018-11-25 11:11 ` Russell King - ARM Linux
2018-11-25 11:57 ` Russell King - ARM Linux
2018-11-25 16:58 ` Aaro Koskinen
2018-11-25 17:14 ` Tony Lindgren
2018-12-17 23:47 ` Aaro Koskinen
2018-12-18 15:55 ` Tony Lindgren
2018-12-17 19:16 ` Aaro Koskinen
2018-12-18 10:11 ` Peter Ujfalusi
2018-11-23 11:49 ` Peter Ujfalusi
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