[Xen-devel] [PATCH 1/3 v3] xen: Refactor 16550 UART code

[Bhupinder Thakur <bhupinder.thakur@xxxxxxxxxx>]

This patch refactors the 8250 UART code so that code can be reused
by later patches, which add support for ACPI based UART
initialization.

Signed-off-by: Bhupinder Thakur <bhupinder.thakur@xxxxxxxxxx>
---
Changes since v2:
- Refactored the code to prepare for later patches.

CC: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CC: George Dunlap <George.Dunlap@xxxxxxxxxxxxx>
CC: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
CC: Jan Beulich <jbeulich@xxxxxxxx>
CC: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
CC: Stefano Stabellini <sstabellini@xxxxxxxxxx>
CC: Tim Deegan <tim@xxxxxxx>
CC: Wei Liu <wei.liu2@xxxxxxxxxx>
CC: Julien Grall <julien.grall@xxxxxxx>

 xen/drivers/char/ns16550.c | 53 ++++++++++++++++++++++++++++++++++------------
 1 file changed, 40 insertions(+), 13 deletions(-)

diff --git a/xen/drivers/char/ns16550.c b/xen/drivers/char/ns16550.c
index e0f8199..c5dfc1e 100644
--- a/xen/drivers/char/ns16550.c
+++ b/xen/drivers/char/ns16550.c
@@ -1462,16 +1462,32 @@ void __init ns16550_init(int index, struct 
ns16550_defaults *defaults)
     ns16550_parse_port_config(uart, (index == 0) ? opt_com1 : opt_com2);
 }
 
+#ifdef CONFIG_ARM
+static void ns16550_vuart_init(struct ns16550 *uart)
+{
+    uart->vuart.base_addr   = uart->io_base;
+    uart->vuart.size        = uart->io_size;
+    uart->vuart.data_off    = UART_THR << uart->reg_shift;
+    uart->vuart.status_off  = UART_LSR << uart->reg_shift;
+    uart->vuart.status      = UART_LSR_THRE | UART_LSR_TEMT;
+}
+#endif
+
+static void ns16550_register_uart(struct ns16550 *uart)
+{
+    /* Register with generic serial driver. */
+    serial_register_uart(uart - ns16550_com, &ns16550_driver, uart);
+}
+
 #ifdef CONFIG_HAS_DEVICE_TREE
-static int __init ns16550_uart_dt_init(struct dt_device_node *dev,
-                                       const void *data)
+
+static int ns16550_init_dt(struct ns16550 **puart,
+                           const struct dt_device_node *dev)
 {
-    struct ns16550 *uart;
     int res;
     u32 reg_shift, reg_width;
     u64 io_size;
-
-    uart = &ns16550_com[0];
+    struct ns16550 *uart = &ns16550_com[0];
 
     ns16550_init_common(uart);
 
@@ -1510,18 +1526,29 @@ static int __init ns16550_uart_dt_init(struct 
dt_device_node *dev,
 
     uart->dw_usr_bsy = dt_device_is_compatible(dev, "snps,dw-apb-uart");
 
-    uart->vuart.base_addr = uart->io_base;
-    uart->vuart.size = uart->io_size;
-    uart->vuart.data_off = UART_THR <<uart->reg_shift;
-    uart->vuart.status_off = UART_LSR<<uart->reg_shift;
-    uart->vuart.status = UART_LSR_THRE|UART_LSR_TEMT;
+    *puart = uart;
 
-    /* Register with generic serial driver. */
-    serial_register_uart(uart - ns16550_com, &ns16550_driver, uart);
+    return 0;
+}
+
+static int __init ns16550_uart_dt_init(struct dt_device_node *dev,
+                                       const void *data)
+{
+    struct ns16550 *uart;
+    int ret;
+
+    ret = ns16550_init_dt(&uart, data);
+
+    if ( ret )
+        return ret;
+
+    ns16550_vuart_init(uart);
+
+    ns16550_register_uart(uart);
 
     dt_device_set_used_by(dev, DOMID_XEN);
 
-    return 0;
+    return ret;
 }
 
 static const struct dt_device_match ns16550_dt_match[] __initconst =
-- 
2.7.4


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