mailbox: pcc: Consolidate subspace doorbell register parsing

Extended PCC subspaces(Type 3 and 4) differ from generic(Type 0) and
HW-Reduced Communication(Type 1 and 2) subspace structures. However some
fields share same offsets and same type of structure can be use to
extract the fields. In order to simplify that, let us move all the doorbell
register parsing into pcc_parse_subspace_db_reg and consolidate there.
It will be easier to extend it if required within the same.
Reviewed-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

drivers/mailbox/pcc.c

@@ -448,6 +448,28 @@ static int pcc_parse_subspace_irq(struct pcc_chan_info *pchan,
 	return 0;
 }
 
+/**
+ * pcc_parse_subspace_db_reg - Parse the PCC doorbell register
+ *
+ * @pchan: Pointer to the PCC channel info structure.
+ * @pcct_entry: Pointer to the ACPI subtable header.
+ *
+ */
+static void pcc_parse_subspace_db_reg(struct pcc_chan_info *pchan,
+				      struct acpi_subtable_header *pcct_entry)
+{
+	struct acpi_pcct_subspace *pcct_ss;
+	struct acpi_generic_address *db_reg;
+
+	pcct_ss = (struct acpi_pcct_subspace *)pcct_entry;
+
+	/* If doorbell is in system memory cache the virt address */
+	db_reg = &pcct_ss->doorbell_register;
+	if (db_reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
+		pchan->db_vaddr = acpi_os_ioremap(db_reg->address,
+						  db_reg->bit_width / 8);
+}
+
 /**
  * acpi_pcc_probe - Parse the ACPI tree for the PCCT.
  *
@@ -513,8 +535,6 @@ static int __init acpi_pcc_probe(void)
 
 	for (i = 0; i < count; i++) {
 		struct pcc_chan_info *pchan = chan_info + i;
-		struct acpi_generic_address *db_reg;
-		struct acpi_pcct_subspace *pcct_ss;
 		pcc_mbox_channels[i].con_priv = pcct_entry;
 
 		if (pcc_mbox_ctrl.txdone_irq) {
@@ -522,13 +542,8 @@ static int __init acpi_pcc_probe(void)
 			if (rc < 0)
 				goto err;
 		}
-		pcct_ss = (struct acpi_pcct_subspace *) pcct_entry;
+		pcc_parse_subspace_db_reg(pchan, pcct_entry);
 
-		/* If doorbell is in system memory cache the virt address */
-		db_reg = &pcct_ss->doorbell_register;
-		if (db_reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
-			pchan->db_vaddr = acpi_os_ioremap(db_reg->address,
-							  db_reg->bit_width / 8);
 		pcct_entry = (struct acpi_subtable_header *)
 			((unsigned long) pcct_entry + pcct_entry->length);
 	}