msm: ipa: change default low watermark for rx buffers

Change the threshold for resubmitting RX buffers to IPA in case
of allocation errors to a bigger number than 0.
In some corner cases a packet from IPA to AP might be larger than
the side of 1 buffer, which can result in IPA stall if threshold
is 0.

CRs-Fixed: 1027726
Change-Id: Ic841de25597c2cd4ce007823f9b9727e858a73cb
Acked-by: Ady Abraham <adya@qti.qualcomm.com>
Signed-off-by: Skylar Chang <chiaweic@codeaurora.org>

drivers/platform/msm/ipa/ipa_v2/ipa_dp.c

@@ -1165,7 +1165,7 @@ void ipa_update_repl_threshold(enum ipa_client_type ipa_client)
 	 * Determine how many buffers/descriptors remaining will
 	 * cause to drop below the yellow WM bar.
 	 */
-	ep->rx_replenish_threshold = ipa_get_sys_yellow_wm()
+	ep->rx_replenish_threshold = ipa_get_sys_yellow_wm(ep->sys)
 					/ ep->sys->rx_buff_sz;
 }
 
@@ -1361,7 +1361,7 @@ int ipa2_setup_sys_pipe(struct ipa_sys_connect_params *sys_in, u32 *clnt_hdl)
 		 * Determine how many buffers/descriptors remaining will
 		 * cause to drop below the yellow WM bar.
 		 */
-		ep->rx_replenish_threshold = ipa_get_sys_yellow_wm()
+		ep->rx_replenish_threshold = ipa_get_sys_yellow_wm(ep->sys)
 						/ ep->sys->rx_buff_sz;
 		/* Only when the WAN pipes are setup, actual threshold will
 		 * be read from the register. So update LAN_CONS ep again with

drivers/platform/msm/ipa/ipa_v2/ipa_i.h

@@ -1911,7 +1911,7 @@ int ipa2_uc_mhi_stop_event_update_channel(int channelHandle);
 int ipa2_uc_mhi_print_stats(char *dbg_buff, int size);
 int ipa_uc_memcpy(phys_addr_t dest, phys_addr_t src, int len);
 u32 ipa_get_num_pipes(void);
-u32 ipa_get_sys_yellow_wm(void);
+u32 ipa_get_sys_yellow_wm(struct ipa_sys_context *sys);
 struct ipa_smmu_cb_ctx *ipa2_get_smmu_ctx(void);
 struct ipa_smmu_cb_ctx *ipa2_get_wlan_smmu_ctx(void);
 struct ipa_smmu_cb_ctx *ipa2_get_uc_smmu_ctx(void);

drivers/platform/msm/ipa/ipa_v2/ipa_utils.c

@@ -44,6 +44,8 @@
 #define IPA_EOT_COAL_GRAN_MIN (1)
 #define IPA_EOT_COAL_GRAN_MAX (16)
 
+#define IPA_DEFAULT_SYS_YELLOW_WM 32
+
 #define IPA_AGGR_BYTE_LIMIT (\
 		IPA_ENDP_INIT_AGGR_N_AGGR_BYTE_LIMIT_BMSK >> \
 		IPA_ENDP_INIT_AGGR_N_AGGR_BYTE_LIMIT_SHFT)
@@ -5074,15 +5076,19 @@ int ipa2_bind_api_controller(enum ipa_hw_type ipa_hw_type,
  * ipa_get_sys_yellow_wm()- Return yellow WM value for IPA SYS pipes.
  *
  * Return value: IPA_YELLOW_MARKER_SYS_CFG_OFST register if IPA_HW_v2.6L,
- *               0 otherwise.
+ *               IPA_DEFAULT_SYS_YELLOW_WM otherwise.
  */
-u32 ipa_get_sys_yellow_wm(void)
+u32 ipa_get_sys_yellow_wm(struct ipa_sys_context *sys)
 {
-	if (ipa_ctx->ipa_hw_type == IPA_HW_v2_6L)
+	if (ipa_ctx->ipa_hw_type == IPA_HW_v2_6L) {
 		return ipa_read_reg(ipa_ctx->mmio,
 			IPA_YELLOW_MARKER_SYS_CFG_OFST);
-	else
+	} else {
+		if (!sys)
 			return 0;
+
+		return IPA_DEFAULT_SYS_YELLOW_WM * sys->rx_buff_sz;
+	}
 }
 EXPORT_SYMBOL(ipa_get_sys_yellow_wm);
 

drivers/platform/msm/ipa/ipa_v3/ipa_dp.c

@@ -68,6 +68,8 @@
 /* The below virtual channel cannot be used by any entity */
 #define IPA_GSI_CH_20_WA_VIRT_CHAN 29
 
+#define IPA_DEFAULT_SYS_YELLOW_WM 32
+
 static struct sk_buff *ipa3_get_skb_ipa_rx(unsigned int len, gfp_t flags);
 static void ipa3_replenish_wlan_rx_cache(struct ipa3_sys_context *sys);
 static void ipa3_replenish_rx_cache(struct ipa3_sys_context *sys);
@@ -2300,7 +2302,7 @@ static void ipa3_fast_replenish_rx_cache(struct ipa3_sys_context *sys)
 
 	queue_work(sys->repl_wq, &sys->repl_work);
 
-	if (rx_len_cached == 0) {
+	if (rx_len_cached <= IPA_DEFAULT_SYS_YELLOW_WM) {
 		if (sys->ep->client == IPA_CLIENT_APPS_WAN_CONS)
 			IPA_STATS_INC_CNT(ipa3_ctx->stats.wan_rx_empty);
 		else if (sys->ep->client == IPA_CLIENT_APPS_LAN_CONS)