1 files changed, 24 insertions, 11 deletions

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 1e364d3ad9c5..f0523916232d 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -744,32 +744,43 @@ static void its_flush_cmd(struct its_node *its, struct its_cmd_block *cmd)
 }
 
 static int its_wait_for_range_completion(struct its_node *its,
-                                         struct its_cmd_block *from,
+                                         u64    prev_idx,
                                          struct its_cmd_block *to)
 {
-        u64 rd_idx, from_idx, to_idx;
+        u64 rd_idx, to_idx, linear_idx;
         u32 count = 1000000;    /* 1s! */
 
-        from_idx = its_cmd_ptr_to_offset(its, from);
+        /* Linearize to_idx if the command set has wrapped around */
         to_idx = its_cmd_ptr_to_offset(its, to);
+        if (to_idx < prev_idx)
+                to_idx += ITS_CMD_QUEUE_SZ;
+
+        linear_idx = prev_idx;
 
         while (1) {
+                s64 delta;
+
                 rd_idx = readl_relaxed(its->base + GITS_CREADR);
 
-                /* Direct case */
-                if (from_idx < to_idx && rd_idx >= to_idx)
-                        break;
+                /*
+                 * Compute the read pointer progress, taking the
+                 * potential wrap-around into account.
+                 */
+                delta = rd_idx - prev_idx;
+                if (rd_idx < prev_idx)
+                        delta += ITS_CMD_QUEUE_SZ;
 
-                /* Wrapped case */
-                if (from_idx >= to_idx && rd_idx >= to_idx && rd_idx < from_idx)
+                linear_idx += delta;
+                if (linear_idx >= to_idx)
                         break;
 
                 count--;
                 if (!count) {
-                        pr_err_ratelimited("ITS queue timeout (%llu %llu %llu)\n",
-                                           from_idx, to_idx, rd_idx);
+                        pr_err_ratelimited("ITS queue timeout (%llu %llu)\n",
+                                           to_idx, linear_idx);
                         return -1;
                 }
+                prev_idx = rd_idx;
                 cpu_relax();
                 udelay(1);
         }
@@ -786,6 +797,7 @@ void name(struct its_node *its,						\
         struct its_cmd_block *cmd, *sync_cmd, *next_cmd;                \
         synctype *sync_obj;                                             \
         unsigned long flags;                                            \
+        u64 rd_idx;                                                     \
                                                                         \
         raw_spin_lock_irqsave(&its->lock, flags);                       \
                                                                         \
@@ -807,10 +819,11 @@ void name(struct its_node *its,						\
         }                                                               \
                                                                         \
 post:                                                                   \
+        rd_idx = readl_relaxed(its->base + GITS_CREADR);                \
         next_cmd = its_post_commands(its);                              \
         raw_spin_unlock_irqrestore(&its->lock, flags);                  \
                                                                         \
-        if (its_wait_for_range_completion(its, cmd, next_cmd))          \
+        if (its_wait_for_range_completion(its, rd_idx, next_cmd))       \
                 pr_err_ratelimited("ITS cmd %ps failed\n", builder);    \
 }