From: Vladimir Oltean <olte...@gmail.com>
Date: Thu, 12 Sep 2019 11:17:11 +0100
> Hi Dave,
>
> On 12/09/2019, David Miller <da...@davemloft.net> wrote:
>> From: Vladimir Oltean <olte...@gmail.com>
>> Date: Tue, 10 Sep 2019 04:34:57 +0300
>>
>>> static int sja1105_ptp_adjfine(struct ptp_clock_info *ptp, long
>>> scaled_ppm)
>>> {
>>> struct sja1105_private *priv = ptp_to_sja1105(ptp);
>>> + const struct sja1105_regs *regs = priv->info->regs;
>>> s64 clkrate;
>>> + int rc;
>> ..
>>> -static int sja1105_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
>>> -{
>>> - struct sja1105_private *priv = ptp_to_sja1105(ptp);
>>> + rc = sja1105_spi_send_int(priv, SPI_WRITE, regs->ptpclkrate,
>>> + &clkrate, 4);
>>
>> You're sending an arbitrary 4 bytes of a 64-bit value. This works on little
>> endian
>> but will not on big endian.
>>
>> Please properly copy this clkrate into a "u32" variable and pass that into
>> sja1105_spi_send_int().
>>
>> It also seems to suggest that you want to use abs() to perform that weird
>> centering around 1 << 31 calculation.
>>
>> Thank you.
>>
>
> It looks 'wrong' but it isn't. The driver uses the 'packing' framework
> (lib/packing.c) which is endian-agnostic (converts between CPU and
> peripheral endianness) and operates on u64 as the CPU word size. On
> the contrary, u32 would not work with the 'packing' API in its current
> form, but I don't see yet any reasons to extend it (packing64,
> packing32 etc).
That's extremely unintuitive and makes auditing patches next to impossible.
