net: ipa: inter-EE interrupts aren't always available

The GSI inter-EE interrupts are not supported prior to IPA v3.5.
Don't attempt to initialize them in gsi_irq_setup() for hardware
that does not support them.

Originally proposed by AngeloGioacchino Del Regno.

Link: https://lore.kernel.org/netdev/20210211175015.200772-4-angelogioacchino.delregno@somainline.org
Signed-off-by: Alex Elder <elder@linaro.org>
Acked-by: AngeloGioacchino Del Regno
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ipa/gsi.c

@@ -210,9 +210,16 @@ static void gsi_irq_setup(struct gsi *gsi)
 	iowrite32(0, gsi->virt + GSI_CNTXT_GLOB_IRQ_EN_OFFSET);
 	iowrite32(0, gsi->virt + GSI_CNTXT_SRC_IEOB_IRQ_MSK_OFFSET);
 
-	/* The inter-EE registers are in the non-adjusted address range */
-	iowrite32(0, gsi->virt_raw + GSI_INTER_EE_SRC_CH_IRQ_MSK_OFFSET);
-	iowrite32(0, gsi->virt_raw + GSI_INTER_EE_SRC_EV_CH_IRQ_MSK_OFFSET);
+	/* The inter-EE interrupts are not supported for IPA v3.0-v3.1 */
+	if (gsi->version > IPA_VERSION_3_1) {
+		u32 offset;
+
+		/* These registers are in the non-adjusted address range */
+		offset = GSI_INTER_EE_SRC_CH_IRQ_MSK_OFFSET;
+		iowrite32(0, gsi->virt_raw + offset);
+		offset = GSI_INTER_EE_SRC_EV_CH_IRQ_MSK_OFFSET;
+		iowrite32(0, gsi->virt_raw + offset);
+	}
 
 	iowrite32(0, gsi->virt + GSI_CNTXT_GSI_IRQ_EN_OFFSET);
 }

drivers/net/ipa/gsi_reg.h

@@ -52,7 +52,8 @@
  */
 #define GSI_EE_REG_ADJUST			0x0000d000	/* IPA v4.5+ */
 
-/* The two inter-EE IRQ register offsets are relative to gsi->virt_raw */
+/* The inter-EE IRQ registers are relative to gsi->virt_raw (IPA v3.5+) */
+
 #define GSI_INTER_EE_SRC_CH_IRQ_MSK_OFFSET \
 			GSI_INTER_EE_N_SRC_CH_IRQ_MSK_OFFSET(GSI_EE_AP)
 #define GSI_INTER_EE_N_SRC_CH_IRQ_MSK_OFFSET(ee) \