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Re: [PATCH 3/5] ns8250: Add base support for MMIO UARTs
From: |
Benjamin Herrenschmidt |
Subject: |
Re: [PATCH 3/5] ns8250: Add base support for MMIO UARTs |
Date: |
Wed, 31 Aug 2022 15:56:05 +1000 |
User-agent: |
Evolution 3.44.1-0ubuntu1 |
On Mon, 2022-05-23 at 19:11 +0200, Sven Anderson wrote:
>
> I had a couple of sleepless nights trying to find out why this didn't
> work for my MMIO UART (Intel Cannon Lake PCH Intel C246), so I
> thought I would share my findings with others in a similar situation.
> (See below.)
>
.../...
>
> This code assumes that the registers are only 8 bit wide. Apparently
> for my chipset they are 32 bits wide, so it only (finally) worked
> when I rewrote this code to address and write full grub_uint32_t
> values, like this:
>
> ------
> volatile grub_uint32_t* p = (void*)(port->mmio_base);
> *(p + reg) = (grub_uint32_t)(value);
> ------
Sorry, I dopped the ball on this for a while. Getting back to it and
will re-submit the patches.
Can you send me a dump of your SPCR table ? I'd like to see if it
properly says "32-bit" there to auto-detect this.
Cheers,
Ben.
- Re: [PATCH 3/5] ns8250: Add base support for MMIO UARTs,
Benjamin Herrenschmidt <=