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From:   Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Subject: Re: [PATCH RFC 2/2] memory: add Renesas RPC-IF driver
To:     "Behme Dirk (CM/ESO2)" <dirk.behme@de.bosch.com>
Cc:     devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        Philipp Zabel <p.zabel@pengutronix.de>,
        Mason Yang <masonccyang@mxic.com.tw>,
        linux-spi@vger.kernel.org, Chris Brandt <chris.brandt@renesas.com>,
        linux-renesas-soc@vger.kernel.org
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 <3a182ac7-8d41-cdc7-2b87-7c503f68a426@de.bosch.com>
Organization: Cogent Embedded
Message-ID: <f21a9444-9541-6558-f5f5-ca0b733768ff@cogentembedded.com>
Date:   Tue, 25 Feb 2020 23:41:45 +0300
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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@de.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@de.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! :-)
   Unfortunately, the SPI dirmap and/or writes are still broken.

> Best regards
> 
> Dirk

MBR, Sergei