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Re: [PATCH v2 5/6] hw/sd: sdhci: Limit block size only when SDHC_BLKSIZE
Re: [PATCH v2 5/6] hw/sd: sdhci: Limit block size only when SDHC_BLKSIZE register is writable
Sat, 20 Feb 2021 14:55:57 +0800
On Fri, Feb 19, 2021 at 2:03 AM Philippe Mathieu-Daudé <email@example.com> wrote:
> On 2/18/21 6:09 PM, Philippe Mathieu-Daudé wrote:
> > On 2/16/21 4:46 AM, Bin Meng wrote:
> >> The codes to limit the maximum block size is only necessary when
> >> SDHC_BLKSIZE register is writable.
> Per "SD Command Generation":
> The Host Driver should not read the SDMA System Address, Block Size
> and Block Count registers during a data transaction unless the
> transfer is stopped because the value is changing and not stable.
> To prevent destruction of registers using data transfer when issuing
> command, the 32-bit Block Count, Block Size, 16-bit Block Count and
> Transfer Mode registers shall be write protected by the Host
> Controller while Command Inhibit (DAT) is set to 1 in the Present
> State register.
> Shouldn't we check for !(s->prnsts & SDHC_DATA_INHIBIT) instead?
Yes, for accurate emulation I think we should.
Current implementation uses !(s->prnsts & (SDHC_DOING_READ |
SDHC_DOING_WRITE)) which eventually is correct, because:
SDHC_DATA_INHIBIT bit is set if either SDHC_DAT_LINE_ACTIVE or
SDHC_DOING_READ is set (SD Host Controller Spec v7.00 chapter 2.2.9
Present State Register)
SDHC_DAT_LINE_ACTIVE bit is set after the end bit of read or write
command, and after end bit of read or write command will generate
SDHC_DOING_READ or SDHC_DOING_WRITE (SD Host Controller Spec v7.00
chapter 2.2.9 Present State Register)