[Xen-devel] [PATCH] arm/acpi: Add Server Base System Architecture UART support

[Shanker Donthineni <shankerd@xxxxxxxxxxxxxx>]

The ARM Server Base System Architecture describes a generic UART
interface. It doesn't support clock control registers to set
baudrate. So, extend the driver probe() to handle SBSA interface
types and set the baudrate to 115200 for SBSA interfaces.

Signed-off-by: Shanker Donthineni <shankerd@xxxxxxxxxxxxxx>
---
https://silver.arm.com/download/download.tm?pv=2950177
 xen/drivers/char/pl011.c | 25 +++++++++++++++++++++----
 1 file changed, 21 insertions(+), 4 deletions(-)

diff --git a/xen/drivers/char/pl011.c b/xen/drivers/char/pl011.c
index 1212d5c..81d095f 100644
--- a/xen/drivers/char/pl011.c
+++ b/xen/drivers/char/pl011.c
@@ -226,14 +226,14 @@ static struct uart_driver __read_mostly pl011_driver = {
     .vuart_info   = pl011_vuart,
 };
 
-static int __init pl011_uart_init(int irq, u64 addr, u64 size)
+static int __init pl011_uart_init(int irq, u64 addr, u64 size, int baud)
 {
     struct pl011 *uart;
 
     uart = &pl011_com;
     uart->irq       = irq;
     uart->clock_hz  = 0x16e3600;
-    uart->baud      = BAUD_AUTO;
+    uart->baud      = baud;
     uart->data_bits = 8;
     uart->parity    = PARITY_NONE;
     uart->stop_bits = 1;
@@ -285,7 +285,7 @@ static int __init pl011_dt_uart_init(struct dt_device_node 
*dev,
         return -EINVAL;
     }
 
-    res = pl011_uart_init(res, addr, size);
+    res = pl011_uart_init(res, addr, size, BAUD_AUTO);
     if ( res < 0 )
     {
         printk("pl011: Unable to initialize\n");
@@ -315,6 +315,7 @@ static int __init pl011_acpi_uart_init(const void *data)
 {
     acpi_status status;
     struct acpi_table_spcr *spcr = NULL;
+    int baud = BAUD_AUTO;
     int res;
 
     status = acpi_get_table(ACPI_SIG_SPCR, 0,
@@ -326,17 +327,23 @@ static int __init pl011_acpi_uart_init(const void *data)
         return -EINVAL;
     }
 
+    if ( (spcr->interface_type == ACPI_DBG2_SBSA_32) ||
+         (spcr->interface_type == ACPI_DBG2_SBSA) )
+        baud = 115200;
+
     /* trigger/polarity information is not available in spcr */
     irq_set_type(spcr->interrupt, IRQ_TYPE_LEVEL_HIGH);
 
     res = pl011_uart_init(spcr->interrupt, spcr->serial_port.address,
-                          PAGE_SIZE);
+                          PAGE_SIZE, baud);
     if ( res < 0 )
     {
         printk("pl011: Unable to initialize\n");
         return res;
     }
 
+
+
     return 0;
 }
 
@@ -344,6 +351,16 @@ ACPI_DEVICE_START(apl011, "PL011 UART", DEVICE_SERIAL)
         .class_type = ACPI_DBG2_PL011,
         .init = pl011_acpi_uart_init,
 ACPI_DEVICE_END
+
+ACPI_DEVICE_START(asbsa_uart, "SBSA UART", DEVICE_SERIAL)
+        .class_type = ACPI_DBG2_SBSA,
+        .init = pl011_acpi_uart_init,
+ACPI_DEVICE_END
+
+ACPI_DEVICE_START(asbsa32_uart, "SBSA32 UART", DEVICE_SERIAL)
+        .class_type = ACPI_DBG2_SBSA_32,
+        .init = pl011_acpi_uart_init,
+ACPI_DEVICE_END
 #endif
 
 /*
-- 
Qualcomm Technologies, Inc. on behalf of Qualcomm Innovation Center, Inc. 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, 
a Linux Foundation Collaborative Project


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