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Date:   Mon, 17 Oct 2022 11:39:29 +0200
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Subject: Re: [PATCH] spi: aspeed: Fix window offset of CE1
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To:     Joel Stanley <joel@jms.id.au>
CC:     <linux-spi@vger.kernel.org>, Mark Brown <broonie@kernel.org>,
        <linux-aspeed@lists.ozlabs.org>, <openbmc@lists.ozlabs.org>,
        Andrew Jeffery <andrew@aj.id.au>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>,
        Chin-Ting Kuo <chin-ting_kuo@aspeedtech.com>
References: <20221016155722.3520802-1-clg@kaod.org>
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From:   =?UTF-8?Q?C=c3=a9dric_Le_Goater?= <clg@kaod.org>
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On 10/17/22 00:43, Joel Stanley wrote:
> On Sun, 16 Oct 2022 at 15:57, Cédric Le Goater <clg@kaod.org> wrote:
>>
>> The offset value of the mapping window in the kernel structure is
>> calculated using the value of the previous window offset. This doesn't
>> reflect how the HW is configured and can lead to erroneous setting of
>> the second flash device (CE1).
> 
> So .offset is expected to be the absolute address of the window, and
> this was okay for the 2400/2500 but was broken on the 2600?

the aspeed_spi_get_windows() routine collects in an array the window/decoding
range setting for each CS, and the offset for CS1 and above is computed from
the offset/size of the previous CS. But this makes an assumption on the fact
ranges are contiguous, which is not necessarily how the HW is configured.

C.

> Reviewed-by: Joel Stanley <joel@jms.id.au>
> 
> 
>>
>> Cc: Chin-Ting Kuo <chin-ting_kuo@aspeedtech.com>
>> Fixes: e3228ed92893 ("spi: spi-mem: Convert Aspeed SMC driver to spi-mem")
>> Signed-off-by: Cédric Le Goater <clg@kaod.org>
>> ---
>>   drivers/spi/spi-aspeed-smc.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/spi/spi-aspeed-smc.c b/drivers/spi/spi-aspeed-smc.c
>> index 33cefcf18392..b90571396a60 100644
>> --- a/drivers/spi/spi-aspeed-smc.c
>> +++ b/drivers/spi/spi-aspeed-smc.c
>> @@ -398,7 +398,7 @@ static void aspeed_spi_get_windows(struct aspeed_spi *aspi,
>>                  windows[cs].cs = cs;
>>                  windows[cs].size = data->segment_end(aspi, reg_val) -
>>                          data->segment_start(aspi, reg_val);
>> -               windows[cs].offset = cs ? windows[cs - 1].offset + windows[cs - 1].size : 0;
>> +               windows[cs].offset = data->segment_start(aspi, reg_val) - aspi->ahb_base_phy;
>>                  dev_vdbg(aspi->dev, "CE%d offset=0x%.8x size=0x%x\n", cs,
>>                           windows[cs].offset, windows[cs].size);
>>          }
>> --
>> 2.37.3
>>