irqchip/gicv3-its: Add a new function for parsing device table BASERn

Only the device table BASERn needs to be handled differently as
compared to all other tables. So, adding a separate function for
easy code maintenance and improved code readability.

Signed-off-by: Shanker Donthineni <shankerd@codeaurora.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index a8a1144..5cfa299 100644 (file)
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -840,6 +840,30 @@ static void its_write_baser(struct its_node *its, struct its_baser *baser,
        baser->val = its_read_baser(its, baser);
 }
 
+static void its_parse_baser_device(struct its_node *its, struct its_baser *baser,
+                                  u32 *order)
+{
+       u64 esz = GITS_BASER_ENTRY_SIZE(its_read_baser(its, baser));
+       u32 ids = its->device_ids;
+       u32 new_order = *order;
+
+       /*
+        * Allocate as many entries as required to fit the
+        * range of device IDs that the ITS can grok... The ID
+        * space being incredibly sparse, this results in a
+        * massive waste of memory.
+        */
+       new_order = max_t(u32, get_order(esz << ids), new_order);
+       if (new_order >= MAX_ORDER) {
+               new_order = MAX_ORDER - 1;
+               ids = ilog2(PAGE_ORDER_TO_SIZE(new_order) / esz);
+               pr_warn("ITS@%pa: Device Table too large, reduce ids %u->%u\n",
+                       &its->phys_base, its->device_ids, ids);
+       }
+
+       *order = new_order;
+}
+
 static void its_free_tables(struct its_node *its)
 {
        int i;
@@ -891,29 +915,8 @@ static int its_alloc_tables(const char *node_name, struct its_node *its)
                if (type == GITS_BASER_TYPE_NONE)
                        continue;
 
-               /*
-                * Allocate as many entries as required to fit the
-                * range of device IDs that the ITS can grok... The ID
-                * space being incredibly sparse, this results in a
-                * massive waste of memory.
-                *
-                * For other tables, only allocate a single page.
-                */
-               if (type == GITS_BASER_TYPE_DEVICE) {
-                       /*
-                        * '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",
-                                       node_name, order);
-                       }
-               }
+               if (type == GITS_BASER_TYPE_DEVICE)
+                       its_parse_baser_device(its, baser, &order);
 
 retry_alloc_baser:
                alloc_pages = (PAGE_ORDER_TO_SIZE(order) / psz);