Re: [PATCH] net: ethernet: ti: davinci_cpdma: fix fixed prio cpdma ctlr configuration

From: Grygorii Strashko
Date: Thu Nov 10 2016 - 19:03:36 EST




On 11/10/2016 01:52 PM, ivan.khoronzhuk wrote:


On 10.11.16 18:37, Grygorii Strashko wrote:


On 11/09/2016 05:56 PM, Ivan Khoronzhuk wrote:


On 09.11.16 23:09, Grygorii Strashko wrote:


On 11/08/2016 07:10 AM, Ivan Khoronzhuk wrote:
The dma ctlr is reseted to 0 while cpdma start, thus cpdma ctlr

I assume this is because cpdma_ctlr_start() does soft reset. Is it
correct?
Probably not. I've seen this register doesn't hold any previous settings
(just trash)

What register CPDMA_DMACONTROL or CPSW_DMACTRL?

after cpdma_ctlr_stop(), actually after last channel is stopped (inside
of cpdma_ctlr_stop()).

So, You are stating that Registers context is changed after stop?

Then cpdma_ctlr_start() just reset it to 0.

"just trash" or "0".

Sry, I do not see how cpdma_ctlr_stop() can affect on registers state :(
and I'd very appreciated if can provide more detailed information.

I've checked again, it was my mistake. It simply reset to 0 while soft
reset.



cannot be configured after cpdma is stopped. So, restore content
of cpdma ctlr while off/on procedure.

Based on net-next/master

^ remove it
sure



Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@xxxxxxxxxx>
---
drivers/net/ethernet/ti/cpsw.c | 6 +-
drivers/net/ethernet/ti/davinci_cpdma.c | 103
+++++++++++++++++---------------
drivers/net/ethernet/ti/davinci_cpdma.h | 2 +
3 files changed, 58 insertions(+), 53 deletions(-)

diff --git a/drivers/net/ethernet/ti/cpsw.c
b/drivers/net/ethernet/ti/cpsw.c
index b1ddf89..4d04b8e 100644
--- a/drivers/net/ethernet/ti/cpsw.c
+++ b/drivers/net/ethernet/ti/cpsw.c
@@ -1376,10 +1376,6 @@ static int cpsw_ndo_open(struct net_device
*ndev)
ALE_ALL_PORTS, ALE_ALL_PORTS, 0, 0);

if (!cpsw_common_res_usage_state(cpsw)) {
- /* setup tx dma to fixed prio and zero offset */
- cpdma_control_set(cpsw->dma, CPDMA_TX_PRIO_FIXED, 1);
- cpdma_control_set(cpsw->dma, CPDMA_RX_BUFFER_OFFSET, 0);
-
/* disable priority elevation */
__raw_writel(0, &cpsw->regs->ptype);

@@ -2710,6 +2706,8 @@ static int cpsw_probe(struct platform_device
*pdev)
dma_params.desc_align = 16;
dma_params.has_ext_regs = true;
dma_params.desc_hw_addr = dma_params.desc_mem_phys;
+ dma_params.rxbuf_offset = 0;
+ dma_params.fixed_prio = 1;

Do we really need this new parameters? Do you have plans to use other
values?
I'm ok if this is static (equally as a bunch of rest in dma_params), no
see reason to use other values,

That's what i wanted to know :) - go static, pls.

it at least now. But the issue is not only in these two parameters and
not only in cpsw_ndo_open().
It touches cpsw_set_channels() also, where ctlr stop/start is present.
In order to not copy cpdma_control_set(cpsw->dma, CPDMA_TX_PRIO_FIXED,
1)...
in all such kind places in eth drivers, better to allow the cpdma to
control it's parameters...

The cpdma ctlr register holds a little more parameters (but only two of
them are set in cpsw)
Maybe there is reason to save them also. Actually I'd seen this problem
when playing with
on/off channel shapers, unfortunately the cpdma ctlr holds this info
also, and it was lost
while on/off (but I'm going to restore it in chan_start()).


I understand you change, but I'm note sure about real root cause :(
so, are you Ok with current version?

No. pls, use constant values and do not introduce additional parameters.
Also, pls update commit message with new information.

--
regards,
-grygorii