From: Guenter Roeck <linux@roeck-us.net>
To: "Cheng, Xuzhou" <Xuzhou.Cheng@windriver.com>
Cc: "Peter Maydell" <peter.maydell@linaro.org>,
"Jean-Christophe Dubois" <jcd@tribudubois.net>,
"Alistair Francis" <alistair@alistair23.me>,
"Philippe Mathieu-Daudé" <f4bug@amsat.org>,
"QEMU Developers" <qemu-devel@nongnu.org>,
qemu-arm <qemu-arm@nongnu.org>, "Bin Meng" <bmeng.cn@gmail.com>
Subject: Re: [PATCH] hw/ssi: imx_spi: Improve chip select handling
Date: Fri, 17 Sep 2021 21:19:23 -0700 [thread overview]
Message-ID: <2cd83a88-952c-6f86-74b2-8c0da3ce4394@roeck-us.net> (raw)
In-Reply-To: <PH0PR11MB52058E0462672E61797758B997DE9@PH0PR11MB5205.namprd11.prod.outlook.com>
On 9/17/21 8:09 PM, Cheng, Xuzhou wrote:
>>> I got some free time in the past days to investigate this issue. Guenter is right, the Linux imx-spi driver does not work on QEMU.
>>>
>>> The reason is that the state of m25p80 machine loops in STATE_READING_DATA state after receiving RDSR command, the new command is ignored. Before sending a new command, the CS line should be pulled to high, this make the state of m25p80 back to IDLE.
>>>
>>> I have same point with Guenter, it's that set CS to 1 when burst is zero. But i don't think it is necessary to set CS to 0 in imx_spi_flush_txfifo(). I will send a new patch to fix this issue.
>>>
>>
>> Thanks a lot for looking into this. If you have a better solution than mine, by all means, please go for it. As I mentioned in my patch, I didn't really like it, but I was unable to find a better solution.
> I am doing some experiment to verify that the new patch is reasonable, so the new patch will be delayed few days.
>
No problem. Note that I'll be traveling for the next 2-3 weeks, and I won't be able
to test any patches during that time.
Guenter
next prev parent reply other threads:[~2021-09-18 4:21 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-08 1:34 [PATCH] hw/ssi: imx_spi: Improve chip select handling Guenter Roeck
2021-09-02 15:58 ` Peter Maydell
2021-09-02 16:09 ` Guenter Roeck
2021-09-02 19:29 ` Peter Maydell
2021-09-04 17:13 ` Guenter Roeck
2021-09-04 23:06 ` Bin Meng
2021-09-04 23:19 ` Philippe Mathieu-Daudé
2021-09-05 2:08 ` Guenter Roeck
2021-09-08 6:29 ` Bin Meng
2021-09-08 6:31 ` Bin Meng
2021-09-08 9:05 ` Cheng, Xuzhou
2021-09-08 16:52 ` Guenter Roeck
2021-09-16 10:21 ` Cheng, Xuzhou
2021-09-16 14:21 ` Guenter Roeck
2021-09-18 3:09 ` Cheng, Xuzhou
2021-09-18 4:19 ` Guenter Roeck [this message]
2021-09-26 2:49 ` Bin Meng
2021-10-01 13:04 ` Guenter Roeck
2021-09-05 2:05 ` Guenter Roeck
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