remoteproc: s/big switch/lookup table/

A lookup table would be easier to extend, and the resulting
code is a bit cleaner.

Reported-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>

2 files changed, 30 insertions, 22 deletions

diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
index 567a3c59b4af..729911b67a9a 100644
--- a/drivers/remoteproc/remoteproc_core.c
+++ b/drivers/remoteproc/remoteproc_core.c
@@ -64,6 +64,8 @@ static DEFINE_KLIST(rprocs, klist_rproc_get, klist_rproc_put);
 
 typedef int (*rproc_handle_resources_t)(struct rproc *rproc,
                                 struct fw_resource *rsc, int len);
+typedef int (*rproc_handle_resource_t)(struct rproc *rproc,
+                                struct fw_resource *rsc);
 
 /*
  * This is the IOMMU fault handler we register with the IOMMU API
@@ -658,44 +660,43 @@ free_mapping:
         return ret;
 }
 
+/*
+ * A lookup table for resource handlers. The indices are defined in
+ * enum fw_resource_type.
+ */
+static rproc_handle_resource_t rproc_handle_rsc[] = {
+        [RSC_CARVEOUT] = rproc_handle_carveout,
+        [RSC_DEVMEM] = rproc_handle_devmem,
+        [RSC_TRACE] = rproc_handle_trace,
+        [RSC_VRING] = rproc_handle_vring,
+        [RSC_VIRTIO_DEV] = NULL, /* handled early upon registration */
+};
+
 /* handle firmware resource entries before booting the remote processor */
 static int
 rproc_handle_boot_rsc(struct rproc *rproc, struct fw_resource *rsc, int len)
 {
         struct device *dev = rproc->dev;
+        rproc_handle_resource_t handler;
         int ret = 0;
 
-        while (len >= sizeof(*rsc)) {
+        for (; len >= sizeof(*rsc); rsc++, len -= sizeof(*rsc)) {
                 dev_dbg(dev, "rsc: type %d, da 0x%llx, pa 0x%llx, len 0x%x, "
                         "id %d, name %s, flags %x\n", rsc->type, rsc->da,
                         rsc->pa, rsc->len, rsc->id, rsc->name, rsc->flags);
 
-                switch (rsc->type) {
-                case RSC_CARVEOUT:
-                        ret = rproc_handle_carveout(rproc, rsc);
-                        break;
-                case RSC_DEVMEM:
-                        ret = rproc_handle_devmem(rproc, rsc);
-                        break;
-                case RSC_TRACE:
-                        ret = rproc_handle_trace(rproc, rsc);
-                        break;
-                case RSC_VRING:
-                        ret = rproc_handle_vring(rproc, rsc);
-                        break;
-                case RSC_VIRTIO_DEV:
-                        /* this one is handled early upon registration */
-                        break;
-                default:
+                if (rsc->type >= RSC_LAST) {
                         dev_warn(dev, "unsupported resource %d\n", rsc->type);
-                        break;
+                        continue;
                 }
 
+                handler = rproc_handle_rsc[rsc->type];
+                if (!handler)
+                        continue;
+
+                ret = handler(rproc, rsc);
                 if (ret)
                         break;
-
-                rsc++;
-                len -= sizeof(*rsc);
         }
 
         return ret;
diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
index b52f78413c5c..ada4cb063dfe 100644
--- a/include/linux/remoteproc.h
+++ b/include/linux/remoteproc.h
@@ -103,6 +103,7 @@ struct fw_resource {
  *                  the virtio device features, 'pa' holds the virtio guest
  *                  features, 'len' holds the virtio status, and 'flags' holds
  *                  the virtio id (currently only VIRTIO_ID_RPMSG is supported).
+ * @RSC_LAST:       just keep this one at the end
  *
  * Most of the resource entries share the basic idea of address/length
  * negotiation with the host: the firmware usually asks (on behalf of the
@@ -115,6 +116,11 @@ struct fw_resource {
  * will contain the expected device addresses (today we actually only support
  * this scheme, as there aren't yet any use cases for dynamically allocated
  * device addresses).
+ *
+ * Please note that these values are used as indices to the rproc_handle_rsc
+ * lookup table, so please keep them sane. Moreover, @RSC_LAST is used to
+ * check the validity of an index before the lookup table is accessed, so
+ * please update it as needed.
  */
 enum fw_resource_type {
         RSC_CARVEOUT    = 0,
@@ -122,6 +128,7 @@ enum fw_resource_type {
         RSC_TRACE       = 2,
         RSC_VRING       = 3,
         RSC_VIRTIO_DEV  = 4,
+        RSC_LAST        = 5,
 };
 
 /**