On Wed, 10 Mar 2021 at 18:56, <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
>
> From: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
>
> From: Alex Elder <elder@xxxxxxxxxx>
>
> [ Upstream commit f849afcc8c3b27d7b50827e95b60557f24184df0 ]
>
> IPA v4.2 has a hardware quirk that requires the AP to allocate GSI
> channels for the modem to use. It is recommended that these modem
> channels get stopped (with a HALT generic command) by the AP when
> its IPA driver gets removed.
>
> The AP has no way of knowing the current state of a modem channel.
> So when the IPA driver issues a HALT command it's possible the
> channel is not running, and in that case we get an error indication.
> This error simply means we didn't need to stop the channel, so we
> can ignore it.
>
> This patch adds an explanation for this situation, and arranges for
> this condition to *not* report an error message.
>
> Signed-off-by: Alex Elder <elder@xxxxxxxxxx>
> Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
> ---
> drivers/net/ipa/gsi.c | 24 +++++++++++++++++++++++-
> 1 file changed, 23 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/ipa/gsi.c b/drivers/net/ipa/gsi.c
> index 2a65efd3e8da..48ee43b89fec 100644
> --- a/drivers/net/ipa/gsi.c
> +++ b/drivers/net/ipa/gsi.c
> @@ -1052,10 +1052,32 @@ static void gsi_isr_gp_int1(struct gsi *gsi)
> u32 result;
> u32 val;
>
> + /* This interrupt is used to handle completions of the two GENERIC
> + * GSI commands. We use these to allocate and halt channels on
> + * the modem's behalf due to a hardware quirk on IPA v4.2. Once
> + * allocated, the modem "owns" these channels, and as a result we
> + * have no way of knowing the channel's state at any given time.
> + *
> + * It is recommended that we halt the modem channels we allocated
> + * when shutting down, but it's possible the channel isn't running
> + * at the time we issue the HALT command. We'll get an error in
> + * that case, but it's harmless (the channel is already halted).
> + *
> + * For this reason, we silently ignore a CHANNEL_NOT_RUNNING error
> + * if we receive it.
> + */
> val = ioread32(gsi->virt + GSI_CNTXT_SCRATCH_0_OFFSET);
> result = u32_get_bits(val, GENERIC_EE_RESULT_FMASK);
> - if (result != GENERIC_EE_SUCCESS_FVAL)
> +
> + switch (result) {
> + case GENERIC_EE_SUCCESS_FVAL:
> + case GENERIC_EE_CHANNEL_NOT_RUNNING_FVAL:
While building stable rc 5.10 for arm64 the build failed due to
the following errors / warnings.
make --silent --keep-going --jobs=8
O=/home/tuxbuild/.cache/tuxmake/builds/1/tmp ARCH=arm64
CROSS_COMPILE=aarch64-linux-gnu- 'HOSTCC=sccache clang' 'CC=sccache
clang'
drivers/net/ipa/gsi.c:1074:7: error: use of undeclared identifier
'GENERIC_EE_CHANNEL_NOT_RUNNING_FVAL'
case GENERIC_EE_CHANNEL_NOT_RUNNING_FVAL:
^
1 error generated.
make[4]: *** [scripts/Makefile.build:279: drivers/net/ipa/gsi.o] Error 1
Reported-by: Linux Kernel Functional Testing <lkft@xxxxxxxxxx>
Build log link,
https://gitlab.com/Linaro/lkft/mirrors/stable/linux-stable-rc/-/jobs/1086862412#L210
--
Linaro LKFT
https://lkft.linaro.org
