[PATCH V6 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 <sukadev at linux.vnet.ibm.com>
Signed-off-by: Haren Myneni <haren at 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 3ab0831..614a27c 100644
--- a/arch/powerpc/platforms/powernv/vas-fault.c
+++ b/arch/powerpc/platforms/powernv/vas-fault.c
@@ -237,6 +237,10 @@ irqreturn_t vas_fault_thread_fn(int irq, void *data)
 		memcpy(crb, fifo, CRB_SIZE);
 		entry->stamp.nx.pswid = FIFO_INVALID_ENTRY;
 		entry->ccw |= 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",
@@ -266,6 +270,11 @@ 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 427a884..1439a6f 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 9ba4605..f0efb98 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