[PATCH v3] irqchip/gicv3-its: ITS table size should not be smaller than PSZ

[Stuart Yoder]

when allocating a device table, if the requested allocation
is smaller than the default granule size of the ITS
then, we need to round up to the default size

Signed-off-by: Minghuan Lian <Minghuan.Lian at freescale.com>
Signed-off-by: Stuart Yoder <stuart.yoder at freescale.com>
---
  -v3 changes
     -updated commit message and added comment
  -would be nice to get this into 4.1 as the kernel will hang booting
   on some systems

 drivers/irqchip/irq-gic-v3-its.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 9687f8a..1b7e155 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -828,7 +828,14 @@ static int its_alloc_tables(struct its_node *its)
 			u64 typer = readq_relaxed(its->base + GITS_TYPER);
 			u32 ids = GITS_TYPER_DEVBITS(typer);
 
-			order = get_order((1UL << ids) * entry_size);
+			/*
+			 * 'order' was initialized earlier to the default page
+			 * granule of the the ITS.  We can't have an allocation
+			 * smaller than that.  If the requested allocation
+			 * is smaller, round up to the default page granule.
+			 */
+			order = max(get_order((1UL << ids) * entry_size),
+				    order);
 			if (order >= MAX_ORDER) {
 				order = MAX_ORDER - 1;
 				pr_warn("%s: Device Table too large, reduce its page order to %u\n",
-- 
2.3.3