uwb: improved MAS allocator and reservation conflict handling

Greatly enhance the MAS allocator:
  - Handle row and column reservations.
  - Permit all the available MAS to be allocated.
  - Follows the WiMedia rules on MAS selection.

Take appropriate action when reservation conflicts are detected.
  - Correctly identify which reservation wins the conflict.
  - Protect alien BP reservations.
  - If an owned reservation loses, resize/move it.
  - Follow the backoff procedure before requesting additional MAS.

When reservations are terminated, move the remaining reservations (if
necessary) so they keep following the MAS allocation rules.

Signed-off-by: Stefano Panella <stefano.panella@csr.com>
Signed-off-by: David Vrabel <david.vrabel@csr.com>

1 files changed, 123 insertions, 37 deletions

diff --git a/drivers/uwb/drp-ie.c b/drivers/uwb/drp-ie.c
index 75491d47806b..2840d7bf9e67 100644
--- a/drivers/uwb/drp-ie.c
+++ b/drivers/uwb/drp-ie.c
@@ -22,6 +22,96 @@
 
 #include "uwb-internal.h"
 
+
+/*
+ * Return the reason code for a reservations's DRP IE.
+ */
+int uwb_rsv_reason_code(struct uwb_rsv *rsv)
+{
+        static const int reason_codes[] = {
+                [UWB_RSV_STATE_O_INITIATED]          = UWB_DRP_REASON_ACCEPTED,
+                [UWB_RSV_STATE_O_PENDING]            = UWB_DRP_REASON_ACCEPTED,
+                [UWB_RSV_STATE_O_MODIFIED]           = UWB_DRP_REASON_MODIFIED,
+                [UWB_RSV_STATE_O_ESTABLISHED]        = UWB_DRP_REASON_ACCEPTED,
+                [UWB_RSV_STATE_O_TO_BE_MOVED]        = UWB_DRP_REASON_ACCEPTED,
+                [UWB_RSV_STATE_O_MOVE_COMBINING]     = UWB_DRP_REASON_MODIFIED,
+                [UWB_RSV_STATE_O_MOVE_REDUCING]      = UWB_DRP_REASON_MODIFIED,
+                [UWB_RSV_STATE_O_MOVE_EXPANDING]     = UWB_DRP_REASON_ACCEPTED,
+                [UWB_RSV_STATE_T_ACCEPTED]           = UWB_DRP_REASON_ACCEPTED,
+                [UWB_RSV_STATE_T_CONFLICT]           = UWB_DRP_REASON_CONFLICT,
+                [UWB_RSV_STATE_T_PENDING]            = UWB_DRP_REASON_PENDING,
+                [UWB_RSV_STATE_T_DENIED]             = UWB_DRP_REASON_DENIED,
+                [UWB_RSV_STATE_T_RESIZED]            = UWB_DRP_REASON_ACCEPTED,
+                [UWB_RSV_STATE_T_EXPANDING_ACCEPTED] = UWB_DRP_REASON_ACCEPTED,
+                [UWB_RSV_STATE_T_EXPANDING_CONFLICT] = UWB_DRP_REASON_CONFLICT,
+                [UWB_RSV_STATE_T_EXPANDING_PENDING]  = UWB_DRP_REASON_PENDING,
+                [UWB_RSV_STATE_T_EXPANDING_DENIED]   = UWB_DRP_REASON_DENIED,
+        };
+
+        return reason_codes[rsv->state];
+}
+
+/*
+ * Return the reason code for a reservations's companion DRP IE .
+ */
+int uwb_rsv_companion_reason_code(struct uwb_rsv *rsv)
+{
+        static const int companion_reason_codes[] = {
+                [UWB_RSV_STATE_O_MOVE_EXPANDING]     = UWB_DRP_REASON_ACCEPTED,
+                [UWB_RSV_STATE_T_EXPANDING_ACCEPTED] = UWB_DRP_REASON_ACCEPTED,
+                [UWB_RSV_STATE_T_EXPANDING_CONFLICT] = UWB_DRP_REASON_CONFLICT,
+                [UWB_RSV_STATE_T_EXPANDING_PENDING]  = UWB_DRP_REASON_PENDING,
+                [UWB_RSV_STATE_T_EXPANDING_DENIED]   = UWB_DRP_REASON_DENIED,
+        };
+
+        return companion_reason_codes[rsv->state];
+}
+
+/*
+ * Return the status bit for a reservations's DRP IE.
+ */
+int uwb_rsv_status(struct uwb_rsv *rsv)
+{
+        static const int statuses[] = {
+                [UWB_RSV_STATE_O_INITIATED]          = 0,
+                [UWB_RSV_STATE_O_PENDING]            = 0,
+                [UWB_RSV_STATE_O_MODIFIED]           = 1,
+                [UWB_RSV_STATE_O_ESTABLISHED]        = 1,
+                [UWB_RSV_STATE_O_TO_BE_MOVED]        = 0,
+                [UWB_RSV_STATE_O_MOVE_COMBINING]     = 1,
+                [UWB_RSV_STATE_O_MOVE_REDUCING]      = 1,
+                [UWB_RSV_STATE_O_MOVE_EXPANDING]     = 1,
+                [UWB_RSV_STATE_T_ACCEPTED]           = 1,
+                [UWB_RSV_STATE_T_CONFLICT]           = 0,
+                [UWB_RSV_STATE_T_PENDING]            = 0,
+                [UWB_RSV_STATE_T_DENIED]             = 0,
+                [UWB_RSV_STATE_T_RESIZED]            = 1,
+                [UWB_RSV_STATE_T_EXPANDING_ACCEPTED] = 1,
+                [UWB_RSV_STATE_T_EXPANDING_CONFLICT] = 1,
+                [UWB_RSV_STATE_T_EXPANDING_PENDING]  = 1,
+                [UWB_RSV_STATE_T_EXPANDING_DENIED]   = 1,
+
+        };
+
+        return statuses[rsv->state];
+}
+
+/*
+ * Return the status bit for a reservations's companion DRP IE .
+ */
+int uwb_rsv_companion_status(struct uwb_rsv *rsv)
+{
+        static const int companion_statuses[] = {
+                [UWB_RSV_STATE_O_MOVE_EXPANDING]     = 0,
+                [UWB_RSV_STATE_T_EXPANDING_ACCEPTED] = 1,
+                [UWB_RSV_STATE_T_EXPANDING_CONFLICT] = 0,
+                [UWB_RSV_STATE_T_EXPANDING_PENDING]  = 0,
+                [UWB_RSV_STATE_T_EXPANDING_DENIED]   = 0,
+        };
+
+        return companion_statuses[rsv->state];
+}
+
 /*
  * Allocate a DRP IE.
  *
@@ -33,16 +123,12 @@
 static struct uwb_ie_drp *uwb_drp_ie_alloc(void)
 {
         struct uwb_ie_drp *drp_ie;
-        unsigned tiebreaker;
 
         drp_ie = kzalloc(sizeof(struct uwb_ie_drp) +
                         UWB_NUM_ZONES * sizeof(struct uwb_drp_alloc),
                         GFP_KERNEL);
         if (drp_ie) {
                 drp_ie->hdr.element_id = UWB_IE_DRP;
-
-                get_random_bytes(&tiebreaker, sizeof(unsigned));
-                uwb_ie_drp_set_tiebreaker(drp_ie, tiebreaker & 1);
         }
         return drp_ie;
 }
@@ -103,43 +189,17 @@ static void uwb_drp_ie_from_bm(struct uwb_ie_drp *drp_ie,
  */
 int uwb_drp_ie_update(struct uwb_rsv *rsv)
 {
-        struct device *dev = &rsv->rc->uwb_dev.dev;
         struct uwb_ie_drp *drp_ie;
-        int reason_code, status;
+        struct uwb_rsv_move *mv;
+        int unsafe;
 
-        switch (rsv->state) {
-        case UWB_RSV_STATE_NONE:
+        if (rsv->state == UWB_RSV_STATE_NONE) {
                 kfree(rsv->drp_ie);
                 rsv->drp_ie = NULL;
                 return 0;
-        case UWB_RSV_STATE_O_INITIATED:
-                reason_code = UWB_DRP_REASON_ACCEPTED;
-                status = 0;
-                break;
-        case UWB_RSV_STATE_O_PENDING:
-                reason_code = UWB_DRP_REASON_ACCEPTED;
-                status = 0;
-                break;
-        case UWB_RSV_STATE_O_MODIFIED:
-                reason_code = UWB_DRP_REASON_MODIFIED;
-                status = 1;
-                break;
-        case UWB_RSV_STATE_O_ESTABLISHED:
-                reason_code = UWB_DRP_REASON_ACCEPTED;
-                status = 1;
-                break;
-        case UWB_RSV_STATE_T_ACCEPTED:
-                reason_code = UWB_DRP_REASON_ACCEPTED;
-                status = 1;
-                break;
-        case UWB_RSV_STATE_T_DENIED:
-                reason_code = UWB_DRP_REASON_DENIED;
-                status = 0;
-                break;
-        default:
-                dev_dbg(dev, "rsv with unhandled state (%d)\n", rsv->state);
-                return -EINVAL;
         }
+        
+        unsafe = rsv->mas.unsafe ? 1 : 0;
 
         if (rsv->drp_ie == NULL) {
                 rsv->drp_ie = uwb_drp_ie_alloc();
@@ -148,9 +208,11 @@ int uwb_drp_ie_update(struct uwb_rsv *rsv)
         }
         drp_ie = rsv->drp_ie;
 
+        uwb_ie_drp_set_unsafe(drp_ie,       unsafe);
+        uwb_ie_drp_set_tiebreaker(drp_ie,   rsv->tiebreaker);
         uwb_ie_drp_set_owner(drp_ie,        uwb_rsv_is_owner(rsv));
-        uwb_ie_drp_set_status(drp_ie,       status);
-        uwb_ie_drp_set_reason_code(drp_ie,  reason_code);
+        uwb_ie_drp_set_status(drp_ie,       uwb_rsv_status(rsv));
+        uwb_ie_drp_set_reason_code(drp_ie,  uwb_rsv_reason_code(rsv));
         uwb_ie_drp_set_stream_index(drp_ie, rsv->stream);
         uwb_ie_drp_set_type(drp_ie,         rsv->type);
 
@@ -168,6 +230,27 @@ int uwb_drp_ie_update(struct uwb_rsv *rsv)
 
         uwb_drp_ie_from_bm(drp_ie, &rsv->mas);
 
+        if (uwb_rsv_has_two_drp_ies(rsv)) {
+                mv = &rsv->mv; 
+                if (mv->companion_drp_ie == NULL) {
+                        mv->companion_drp_ie = uwb_drp_ie_alloc();
+                        if (mv->companion_drp_ie == NULL)
+                                return -ENOMEM;
+                }
+                drp_ie = mv->companion_drp_ie;
+                
+                /* keep all the same configuration of the main drp_ie */
+                memcpy(drp_ie, rsv->drp_ie, sizeof(struct uwb_ie_drp));
+                
+
+                /* FIXME: handle properly the unsafe bit */
+                uwb_ie_drp_set_unsafe(drp_ie,       1);
+                uwb_ie_drp_set_status(drp_ie,       uwb_rsv_companion_status(rsv));
+                uwb_ie_drp_set_reason_code(drp_ie,  uwb_rsv_companion_reason_code(rsv));
+        
+                uwb_drp_ie_from_bm(drp_ie, &mv->companion_mas);
+        }
+
         rsv->ie_valid = true;
         return 0;
 }
@@ -218,6 +301,8 @@ void uwb_drp_ie_to_bm(struct uwb_mas_bm *bm, const struct uwb_ie_drp *drp_ie)
         u8 zone;
         u16 zone_mask;
 
+        bitmap_zero(bm->bm, UWB_NUM_MAS);
+
         for (cnt = 0; cnt < numallocs; cnt++) {
                 alloc = &drp_ie->allocs[cnt];
                 zone_bm = le16_to_cpu(alloc->zone_bm);
@@ -229,3 +314,4 @@ void uwb_drp_ie_to_bm(struct uwb_mas_bm *bm, const struct uwb_ie_drp *drp_ie)
                 }
         }
 }
+