From: Nicholas Piggin <npiggin@gmail.com>
To: "broonie@kernel.org" <broonie@kernel.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
"linux-spi@vger.kernel.org" <linux-spi@vger.kernel.org>,
"stable@vger.kernel.org" <stable@vger.kernel.org>
Subject: Re: [PATCH] spi: fsl-espi: Only process interrupts for expected events
Date: Mon, 14 Sep 2020 12:28:34 +1000 [thread overview]
Message-ID: <1600050281.5iiy8pkb7z.astroid@bobo.none> (raw)
In-Reply-To: <ecedc71d-100a-7d7a-ff7f-ef1a3086dd74@alliedtelesis.co.nz>
Excerpts from Chris Packham's message of September 14, 2020 8:03 am:
> Hi All,
>
> On 4/09/20 12:28 pm, Chris Packham wrote:
>> The SPIE register contains counts for the TX FIFO so any time the irq
>> handler was invoked we would attempt to process the RX/TX fifos. Use the
>> SPIM value to mask the events so that we only process interrupts that
>> were expected.
>>
>> This was a latent issue exposed by commit 3282a3da25bd ("powerpc/64:
>> Implement soft interrupt replay in C").
>>
>> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
>> Cc: stable@vger.kernel.org
>> ---
> ping?
I don't know the code/hardware but thanks for tracking this down.
Was there anything more to be done with Jocke's observations, or would
that be a follow-up patch if anything?
If this patch fixes your problem it should probably go in, unless there
are any objections.
Thanks,
Nick
>>
>> Notes:
>> I've tested this on a T2080RDB and a custom board using the T2081 SoC. With
>> this change I don't see any spurious instances of the "Transfer done but
>> SPIE_DON isn't set!" or "Transfer done but rx/tx fifo's aren't empty!" messages
>> and the updates to spi flash are successful.
>>
>> I think this should go into the stable trees that contain 3282a3da25bd but I
>> haven't added a Fixes: tag because I think 3282a3da25bd exposed the issue as
>> opposed to causing it.
>>
>> drivers/spi/spi-fsl-espi.c | 5 +++--
>> 1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/spi/spi-fsl-espi.c b/drivers/spi/spi-fsl-espi.c
>> index 7e7c92cafdbb..cb120b68c0e2 100644
>> --- a/drivers/spi/spi-fsl-espi.c
>> +++ b/drivers/spi/spi-fsl-espi.c
>> @@ -574,13 +574,14 @@ static void fsl_espi_cpu_irq(struct fsl_espi *espi, u32 events)
>> static irqreturn_t fsl_espi_irq(s32 irq, void *context_data)
>> {
>> struct fsl_espi *espi = context_data;
>> - u32 events;
>> + u32 events, mask;
>>
>> spin_lock(&espi->lock);
>>
>> /* Get interrupt events(tx/rx) */
>> events = fsl_espi_read_reg(espi, ESPI_SPIE);
>> - if (!events) {
>> + mask = fsl_espi_read_reg(espi, ESPI_SPIM);
>> + if (!(events & mask)) {
>> spin_unlock(&espi->lock);
>> return IRQ_NONE;
>> }
next prev parent reply other threads:[~2020-09-14 2:28 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-04 0:28 [PATCH] spi: fsl-espi: Only process interrupts for expected events Chris Packham
2020-09-13 22:03 ` Chris Packham
2020-09-14 2:28 ` Nicholas Piggin [this message]
2020-09-14 9:06 ` Joakim Tjernlund
2020-09-21 21:40 ` Mark Brown
2020-09-23 20:27 ` Heiner Kallweit
2020-09-23 21:01 ` Chris Packham
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