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(a)alliedtelesis.co.nz>
Cc: stable(a)vger.kernel.org
---
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;
}
--
2.28.0
The following commit has been merged into the x86/urgent branch of tip:
Commit-ID: 86a82ae0b5095ea24c55898a3f025791e7958b21
Gitweb: https://git.kernel.org/tip/86a82ae0b5095ea24c55898a3f025791e7958b21
Author: Thomas Gleixner <tglx(a)linutronix.de>
AuthorDate: Wed, 23 Sep 2020 17:46:20 +02:00
Committer: Thomas Gleixner <tglx(a)linutronix.de>
CommitterDate: Wed, 23 Sep 2020 22:44:56 +02:00
x86/ioapic: Unbreak check_timer()
Several people reported in the kernel bugzilla that between v4.12 and v4.13
the magic which works around broken hardware and BIOSes to find the proper
timer interrupt delivery mode stopped working for some older affected
platforms which need to fall back to ExtINT delivery mode.
The reason is that the core code changed to keep track of the masked and
disabled state of an interrupt line more accurately to avoid the expensive
hardware operations.
That broke an assumption in i8259_make_irq() which invokes
disable_irq_nosync();
irq_set_chip_and_handler();
enable_irq();
Up to v4.12 this worked because enable_irq() unconditionally unmasked the
interrupt line, but after the state tracking improvements this is not
longer the case because the IO/APIC uses lazy disabling. So the line state
is unmasked which means that enable_irq() does not call into the new irq
chip to unmask it.
In principle this is a shortcoming of the core code, but it's more than
unclear whether the core code should try to reset state. At least this
cannot be done unconditionally as that would break other existing use cases
where the chip type is changed, e.g. when changing the trigger type, but
the callers expect the state to be preserved.
As the way how check_timer() is switching the delivery modes is truly
unique, the obvious fix is to simply unmask the i8259 manually after
changing the mode to ExtINT delivery and switching the irq chip to the
legacy PIC.
Note, that the fixes tag is not really precise, but identifies the commit
which broke the assumptions in the IO/APIC and i8259 code and that's the
kernel version to which this needs to be backported.
Fixes: bf22ff45bed6 ("genirq: Avoid unnecessary low level irq function calls")
Reported-by: p_c_chan(a)hotmail.com
Reported-by: ecm4(a)mail.com
Reported-by: perdigao1(a)yahoo.com
Reported-by: matzes(a)users.sourceforge.net
Reported-by: rvelascog(a)gmail.com
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Tested-by: p_c_chan(a)hotmail.com
Tested-by: matzes(a)users.sourceforge.net
Cc: stable(a)vger.kernel.org
Link: https://bugzilla.kernel.org/show_bug.cgi?id=197769
---
arch/x86/kernel/apic/io_apic.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 779a89e..21f9c7f 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -2243,6 +2243,7 @@ static inline void __init check_timer(void)
legacy_pic->init(0);
legacy_pic->make_irq(0);
apic_write(APIC_LVT0, APIC_DM_EXTINT);
+ legacy_pic->unmask(0);
unlock_ExtINT_logic();