[PATCH] irqchip/gic-v4: Fix non-stick page size error for setup GITS_BASER

From: Shaokun Zhang
Date: Fri Mar 13 2020 - 04:47:21 EST


From: Nianyao Tang <tangnianyao@xxxxxxxxxx>

There is an error when ITS is probed if hw GITS_BASER<2>
only supports psz=SZ_16K while GITS_BASER<1> only supports psz=SZ_4K.
In its_alloc_tables, it has updated GITS_BASER<1>.psz and uses
psz=SZ_4K for setup GITS_BASER<2>, and would fail in writing
GITS_BASER<2>.psz=SZ_4K. 4K PAGE is the smallest and shall stop retry
for other page sizes.

That latter GITS_BASER<n>.psz is larger than former, will lead
to similar error.

[ 0.000000] ITS@0x0000000660000000: Virtual CPUs doesn't stick: ba1f0824404004ff ba1f0824404005ff
[ 0.000000] ITS@0x0000000660000000: failed probing (-6)
[ 0.000000] ITS: No ITS available, not enabling LPIs

>From GIC SPEC document, it's allowed for this implematation, the latter
GITS_BASER<n>.psz is larger than the former.
Let's fix this error with following patch.

Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Marc Zyngier <maz@xxxxxxxxxx>
Signed-off-by: Nianyao Tang <tangnianyao@xxxxxxxxxx>
Signed-off-by: Shaokun Zhang <zhangshaokun@xxxxxxxxxxxxx>
---
drivers/irqchip/irq-gic-v3-its.c | 1 -
1 file changed, 1 deletion(-)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 83b1186..59bf8d6 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -2341,7 +2341,6 @@ static int its_alloc_tables(struct its_node *its)
}

/* Update settings which will be used for next BASERn */
- psz = baser->psz;
cache = baser->val & GITS_BASER_CACHEABILITY_MASK;
shr = baser->val & GITS_BASER_SHAREABILITY_MASK;
}
--
1.9.1