linux-kernel - Re: [PATCH RFC 2/2] memory: add Renesas RPC-IF driver

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Message-ID: <b7d64c11-473c-e703-0e5e-55b909861175@de.bosch.com>
Date:   Wed, 26 Feb 2020 10:54:31 +0100
From:   "Behme Dirk (CM/ESO2)" <dirk.behme@...bosch.com>
To:     Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
CC:     <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        Mason Yang <masonccyang@...c.com.tw>,
        <linux-spi@...r.kernel.org>,
        Chris Brandt <chris.brandt@...esas.com>,
        <linux-renesas-soc@...r.kernel.org>,
        Geert Uytterhoeven <geert@...ux-m68k.org>
Subject: Re: [PATCH RFC 2/2] memory: add Renesas RPC-IF driver

Hi Sergei,

On 25.02.2020 21:41, Sergei Shtylyov wrote:
> On 02/25/2020 12:33 PM, Behme Dirk (CM/ESO2) wrote:
> 
>>>>>>    From d72b805cc461ab1e9747c973e9be84e7abb8f828 Mon Sep 17 00:00:00 2001
>>>>>> From: Dirk Behme <dirk.behme@...bosch.com>
>>>>>> Date: Tue, 4 Feb 2020 08:39:31 +0100
>>>>>> Subject: [PATCH] memory: renesas-rpc-if: Correct the STRTIM and some other
>>>>>>     clean up
>>>>>>
>>>>>> This is required to make the driver work correctly in my M3 environment.
>>>>>>
>>>>>> Signed-off-by: Dirk Behme <dirk.behme@...bosch.com>
>>>>>> ---
>>>>>>     drivers/memory/renesas-rpc-if.c | 42 ++++++++++++++++++++-------------
>>>>>>     1 file changed, 25 insertions(+), 17 deletions(-)
>>>>>>
>>>>>> diff --git a/drivers/memory/renesas-rpc-if.c b/drivers/memory/renesas-rpc-if.c
>>>>>> index 04be92b64bfa..f4356b066384 100644
>>>>>> --- a/drivers/memory/renesas-rpc-if.c
>>>>>> +++ b/drivers/memory/renesas-rpc-if.c
>>>>> [...]
>>>>>> @@ -513,19 +525,15 @@ ssize_t rpcif_dirmap_read(struct rpcif *rpc, u64 offs, size_t len, void *buf)
>>>>>>         pm_runtime_get_sync(rpc->dev);
>>>>>>
>>>>>>         regmap_update_bits(rpc->regmap, RPCIF_CMNCR, RPCIF_CMNCR_MD, 0);
>>>>>> -    regmap_write(rpc->regmap, RPCIF_DRCR,
>>>>>> -             RPCIF_DRCR_RBURST(32) | RPCIF_DRCR_RBE);
>>>>>> -    regmap_write(rpc->regmap, RPCIF_DRCMR, rpc->command);
>>>>>> -    regmap_write(rpc->regmap, RPCIF_DREAR,
>>>>>> -             RPCIF_DREAR_EAV(offs >> 25) | RPCIF_DREAR_EAC(1));
>>>>>> -    regmap_write(rpc->regmap, RPCIF_DROPR, rpc->option);
>>>>>> -    regmap_write(rpc->regmap, RPCIF_DRENR,
>>>>>> -             rpc->enable & ~RPCIF_SMENR_SPIDE(0xF));
>>>>>> -    regmap_write(rpc->regmap, RPCIF_DRDMCR, rpc->dummy);
>>>>>> -    regmap_write(rpc->regmap, RPCIF_DRDRENR, rpc->ddr);
>>>>>
>>>>>       The driver somehow works only with this left in place (with 2 bytes eaten
>>>>> as before), otherwise all the flash reads all 0xff (via dirmap).
>>>>
>>>>
>>>> Do you boot from hyperflash?
>>>
>>>      No, I have arewto say 'cpld write 30 1' in U-Boot before a boot a kernel.
> 
>     s/arewto/to/. :-)
> 
>>> Normally, the V3x Starter Kit boards are wired for the QSPI flash chips.
>>>
>>>> The system I'm using for testing boots from hyperflash. So most probably all registers
>>>> I don't touch in the driver are put into a reasonable state by the boot code, already.
>>>> If you don't boot from hyperflash, that at least would explain our different behavior.
>>>
>>>      Yes. Mind dumping the registers and sending to me?
>>
>> Using the attached debug patch (0001-memory-renesas-rpc-if-DEBUG-Dump-register-
>> content.patch) on a r8a7796 system booting from Hyperflash with above register
> dropping reverted (i.e. including touching these registers) I get
>>
>> Before:
>> RPCIF_DRCR:    0x00000000
>> RPCIF_DRCMR:   0x00a00000
>> RPCIF_DREAR:   0x00000000
>> RPCIF_DROPR:   0x00000000
>> RPCIF_DRENR:   0xa222d400
>> RPCIF_DRDMCR:  0x0000000e
>> RPCIF_DRDRENR: 0x00005101
>>
>> After:
>> RPCIF_DRCR:    0x001f0100
>> RPCIF_DRCMR:   0x00a00000
>> RPCIF_DREAR:   0x00010001
>> RPCIF_DROPR:   0x00000000
>> RPCIF_DRENR:   0xa202d400
>> RPCIF_DRDMCR:  0x0000000e
>> RPCIF_DRDRENR: 0x00005101
>>
>> Comparing that, just 3 registers are different between my working version ("Before") and the version which shows the 2-byte offset ("After"): RPCIF_DRCR, RPCIF_DREAR and RPCIF_DRENR. With try & error, at least in my setup, I was able to reduce this to just RPCIF_DRCR. Dropping the burst mode I was able to 'fix' the two byte offset issue.
> 
>     ACK! Thanks a lot for finding it! :-)
>     That's what I get on the first dirmap read:
> 
> Before:
> RPCIF_CMNCR:   0x81fff301
> RPCIF_DRCR:    0x00000000
> RPCIF_DRCMR:   0x00030000
> RPCIF_DREAR:   0x00000000
> RPCIF_DROPR:   0x00000000
> RPCIF_DRENR:   0x00004700
> RPCIF_DRDMCR:  0x00000000
> RPCIF_DRDRENR: 0x00000000
> 
> After:
> RPCIF_CMNCR:   0x01fff301
> RPCIF_DRCR:    0x001f0100
> RPCIF_DRCMR:   0x00800000
> RPCIF_DREAR:   0x00000001
> RPCIF_DROPR:   0x00000000
> RPCIF_DRENR:   0xa202d400
> RPCIF_DRDMCR:  0x0000000e
> RPCIF_DRDRENR: 0x00005101
> 
>> Do you like to give the attached 0001-memory-renesas-rpc-if-Don-t-use-burst-mode-on-read.patch a try in your setup?
> 
>     Works like charm! :-)


Good news, thanks! :)


>     Unfortunately, the SPI dirmap and/or writes are still broken.


I'm unsure about which function we are talking for "SPI dirmap"?

Regarding writes, in rpcif_io_xfer() in RPCIF_DATA_IN we have an 
additional place where burst mode is enabled:

if (!(smenr & RPCIF_SMENR_ADE(0xf)) && rpc->dirmap) {
...
regmap_write(rpc->regmap, RPCIF_DRCR,
	RPCIF_DRCR_RBURST(32) | RPCIF_DRCR_RBE);
...

Maybe it's worth a try to replace this by just 0, as well:

regmap_write(rpc->regmap, RPCIF_DRCR, 0);

But of course, this is guessing, as I'm not sure if this

if (!(smenr & RPCIF_SMENR_ADE(0xf)) && rpc->dirmap) {

path is taken, at all?


Or even better, if you could adapt the "before / after" debug patch to 
the path which are still not working for you and share it and the 
results, we could compare it with my setup, too :)

Dirk