[PATCH v8 12/14] powerpc/vas: Return credits after handling fault

[Haren Myneni]

NX expects OS to return credit for send window after processing each
fault. Also credit has to be returned even for fault window.

Signed-off-by: Sukadev Bhattiprolu <suka...@linux.vnet.ibm.com>
Signed-off-by: Haren Myneni <ha...@linux.ibm.com>
---
 arch/powerpc/platforms/powernv/vas-fault.c  |  9 +++++++++
 arch/powerpc/platforms/powernv/vas-window.c | 17 +++++++++++++++++
 arch/powerpc/platforms/powernv/vas.h        |  1 +
 3 files changed, 27 insertions(+)

diff --git a/arch/powerpc/platforms/powernv/vas-fault.c 
b/arch/powerpc/platforms/powernv/vas-fault.c
index 40e1de4..292f7ba 100644
--- a/arch/powerpc/platforms/powernv/vas-fault.c
+++ b/arch/powerpc/platforms/powernv/vas-fault.c
@@ -238,6 +238,10 @@ irqreturn_t vas_fault_thread_fn(int irq, void *data)
                memcpy(crb, fifo, CRB_SIZE);
                entry->stamp.nx.pswid = cpu_to_be32(FIFO_INVALID_ENTRY);
                entry->ccw |= cpu_to_be32(CCW0_INVALID);
+               /*
+                * Return credit for the fault window.
+                */
+               vas_return_credit(vinst->fault_win, 0);
                mutex_unlock(&vinst->mutex);
 
                pr_devel("VAS[%d] fault_fifo %p, fifo %p, fault_crbs %d\n",
@@ -267,6 +271,11 @@ irqreturn_t vas_fault_thread_fn(int irq, void *data)
                }
 
                update_csb(window, crb);
+               /*
+                * Return credit for send window after processing
+                * fault CRB.
+                */
+               vas_return_credit(window, 1);
        } while (true);
 }
 
diff --git a/arch/powerpc/platforms/powernv/vas-window.c 
b/arch/powerpc/platforms/powernv/vas-window.c
index 6658ccc..20a2a8b 100644
--- a/arch/powerpc/platforms/powernv/vas-window.c
+++ b/arch/powerpc/platforms/powernv/vas-window.c
@@ -1318,6 +1318,23 @@ int vas_win_close(struct vas_window *window)
 }
 EXPORT_SYMBOL_GPL(vas_win_close);
 
+/*
+ * Return credit for the given window.
+ */
+void vas_return_credit(struct vas_window *window, bool tx)
+{
+       uint64_t val;
+
+       val = 0ULL;
+       if (tx) { /* send window */
+               val = SET_FIELD(VAS_TX_WCRED, val, 1);
+               write_hvwc_reg(window, VREG(TX_WCRED_ADDER), val);
+       } else {
+               val = SET_FIELD(VAS_LRX_WCRED, val, 1);
+               write_hvwc_reg(window, VREG(LRX_WCRED_ADDER), val);
+       }
+}
+
 struct vas_window *vas_pswid_to_window(struct vas_instance *vinst,
                uint32_t pswid)
 {
diff --git a/arch/powerpc/platforms/powernv/vas.h 
b/arch/powerpc/platforms/powernv/vas.h
index bc728d7..8c39a7d 100644
--- a/arch/powerpc/platforms/powernv/vas.h
+++ b/arch/powerpc/platforms/powernv/vas.h
@@ -428,6 +428,7 @@ struct vas_winctx {
 extern void vas_window_free_dbgdir(struct vas_window *win);
 extern int vas_setup_fault_window(struct vas_instance *vinst);
 extern irqreturn_t vas_fault_thread_fn(int irq, void *data);
+extern void vas_return_credit(struct vas_window *window, bool tx);
 extern struct vas_window *vas_pswid_to_window(struct vas_instance *vinst,
                                                uint32_t pswid);
 
-- 
1.8.3.1