IB/hfi1: Add RSM rule for user FECN handling

Add a receive side mapping rule to extract expected user packets with
the FECN bit set and place them in an eager buffer.  This will allow
user libraries to recognize that a FECN was sent when using header
suppression and respond appropriately.

Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

diff --git a/drivers/staging/rdma/hfi1/chip.c b/drivers/staging/rdma/hfi1/chip.c
index b5edc3a..386309c 100644 (file)
--- a/drivers/staging/rdma/hfi1/chip.c
+++ b/drivers/staging/rdma/hfi1/chip.c
@@ -1034,6 +1034,8 @@ static void read_planned_down_reason_code(struct hfi1_devdata *dd, u8 *pdrrc);
 static void handle_temp_err(struct hfi1_devdata *);
 static void dc_shutdown(struct hfi1_devdata *);
 static void dc_start(struct hfi1_devdata *);
+static int qos_rmt_entries(struct hfi1_devdata *dd, unsigned int *mp,
+                          unsigned int *np);
 
 /*
  * Error interrupt table entry.  This is used as input to the interrupt
@@ -12628,6 +12630,8 @@ static int set_up_context_variables(struct hfi1_devdata *dd)
        int total_contexts;
        int ret;
        unsigned ngroups;
+       int qos_rmt_count;
+       int user_rmt_reduced;
 
        /*
         * Kernel receive contexts:
@@ -12683,6 +12687,19 @@ static int set_up_context_variables(struct hfi1_devdata *dd)
                total_contexts = num_kernel_contexts + num_user_contexts;
        }
 
+       /* each user context requires an entry in the RMT */
+       qos_rmt_count = qos_rmt_entries(dd, NULL, NULL);
+       if (qos_rmt_count + num_user_contexts > NUM_MAP_ENTRIES) {
+               user_rmt_reduced = NUM_MAP_ENTRIES - qos_rmt_count;
+               dd_dev_err(dd,
+                          "RMT size is reducing the number of user receive contexts from %d to %d\n",
+                          (int)num_user_contexts,
+                          user_rmt_reduced);
+               /* recalculate */
+               num_user_contexts = user_rmt_reduced;
+               total_contexts = num_kernel_contexts + num_user_contexts;
+       }
+
        /* the first N are kernel contexts, the rest are user contexts */
        dd->num_rcv_contexts = total_contexts;
        dd->n_krcv_queues = num_kernel_contexts;
@@ -13633,6 +13650,72 @@ bail:
        init_qpmap_table(dd, FIRST_KERNEL_KCTXT, dd->n_krcv_queues - 1);
 }
 
+static void init_user_fecn_handling(struct hfi1_devdata *dd,
+                                   struct rsm_map_table *rmt)
+{
+       struct rsm_rule_data rrd;
+       u64 reg;
+       int i, idx, regoff, regidx;
+       u8 offset;
+
+       /* there needs to be enough room in the map table */
+       if (rmt->used + dd->num_user_contexts >= NUM_MAP_ENTRIES) {
+               dd_dev_err(dd, "User FECN handling disabled - too many user contexts allocated\n");
+               return;
+       }
+
+       /*
+        * RSM will extract the destination context as an index into the
+        * map table.  The destination contexts are a sequential block
+        * in the range first_user_ctxt...num_rcv_contexts-1 (inclusive).
+        * Map entries are accessed as offset + extracted value.  Adjust
+        * the added offset so this sequence can be placed anywhere in
+        * the table - as long as the entries themselves do not wrap.
+        * There are only enough bits in offset for the table size, so
+        * start with that to allow for a "negative" offset.
+        */
+       offset = (u8)(NUM_MAP_ENTRIES + (int)rmt->used -
+                                               (int)dd->first_user_ctxt);
+
+       for (i = dd->first_user_ctxt, idx = rmt->used;
+                               i < dd->num_rcv_contexts; i++, idx++) {
+               /* replace with identity mapping */
+               regoff = (idx % 8) * 8;
+               regidx = idx / 8;
+               reg = rmt->map[regidx];
+               reg &= ~(RCV_RSM_MAP_TABLE_RCV_CONTEXT_A_MASK << regoff);
+               reg |= (u64)i << regoff;
+               rmt->map[regidx] = reg;
+       }
+
+       /*
+        * For RSM intercept of Expected FECN packets:
+        * o packet type 0 - expected
+        * o match on F (bit 95), using select/match 1, and
+        * o match on SH (bit 133), using select/match 2.
+        *
+        * Use index 1 to extract the 8-bit receive context from DestQP
+        * (start at bit 64).  Use that as the RSM map table index.
+        */
+       rrd.offset = offset;
+       rrd.pkt_type = 0;
+       rrd.field1_off = 95;
+       rrd.field2_off = 133;
+       rrd.index1_off = 64;
+       rrd.index1_width = 8;
+       rrd.index2_off = 0;
+       rrd.index2_width = 0;
+       rrd.mask1 = 1;
+       rrd.value1 = 1;
+       rrd.mask2 = 1;
+       rrd.value2 = 1;
+
+       /* add rule 1 */
+       add_rsm_rule(dd, 1, &rrd);
+
+       rmt->used += dd->num_user_contexts;
+}
+
 static void init_rxe(struct hfi1_devdata *dd)
 {
        struct rsm_map_table *rmt;
@@ -13643,6 +13726,7 @@ static void init_rxe(struct hfi1_devdata *dd)
        rmt = alloc_rsm_map_table(dd);
        /* set up QOS, including the QPN map table */
        init_qos(dd, rmt);
+       init_user_fecn_handling(dd, rmt);
        complete_rsm_map_table(dd, rmt);
        kfree(rmt);