[Xen-devel] [PATCH v3 01/13] xen: arm64: Add 8250 earlyprintk support

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

From: Pranavkumar Sawargaonkar <pranavkumar@xxxxxxxxxx>

Extracted from "Basic Platform support for APM X-Gene Storm."

Signed-off-by: Anup Patel <anup.patel@xxxxxxxxxx>
Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@xxxxxxxxxx>

Reworked into generic 8250 driver, use EARLY_UART_REG_SHIFT.

While there observe a missing shift in the arm32 version (UART_THR is zero so
it doesn't really matter). Changed for consistency.

Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
---
v2: Drop unused early_uart_init macro
---
 xen/arch/arm/Rules.mk             |    6 +++++
 xen/arch/arm/arm64/debug-8250.inc |   45 +++++++++++++++++++++++++++++++++++++
 2 files changed, 51 insertions(+)
 create mode 100644 xen/arch/arm/arm64/debug-8250.inc

diff --git a/xen/arch/arm/Rules.mk b/xen/arch/arm/Rules.mk
index c27c2eb..aaa203e 100644
--- a/xen/arch/arm/Rules.mk
+++ b/xen/arch/arm/Rules.mk
@@ -82,6 +82,12 @@ EARLY_PRINTK_INC := 8250
 EARLY_UART_BASE_ADDRESS := 0xF0406B00
 EARLY_UART_REG_SHIFT := 2
 endif
+ifeq ($(CONFIG_EARLY_PRINTK), xgene-storm)
+EARLY_PRINTK_INC := 8250
+EARLY_PRINTK_BAUD := 115200
+EARLY_UART_BASE_ADDRESS := 0x1c020000
+EARLY_UART_REG_SHIFT := 2
+endif
 
 ifneq ($(EARLY_PRINTK_INC),)
 EARLY_PRINTK := y
diff --git a/xen/arch/arm/arm64/debug-8250.inc 
b/xen/arch/arm/arm64/debug-8250.inc
new file mode 100644
index 0000000..158549a
--- /dev/null
+++ b/xen/arch/arm/arm64/debug-8250.inc
@@ -0,0 +1,45 @@
+/*
+ * xen/arch/arm/arm64/debug-8250.inc
+ *
+ * 8250 specific debug code
+ *
+ * Copyright (c) 2013 Applied Micro.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <xen/8250-uart.h>
+
+/* UART wait UART to be ready to transmit
+ * xb: register which contains the UART base address
+ * c: scratch register */
+.macro early_uart_ready xb c
+1:
+       ldrb  w\c, [\xb, #UART_LSR << EARLY_UART_REG_SHIFT]
+       and w\c, w\c, #UART_LSR_THRE
+       cmp w\c, #UART_LSR_THRE
+       b.ne 1b
+.endm
+
+/* UART transmit character
+ * xb: register which contains the UART base address
+ * wt: register which contains the character to transmit */
+.macro early_uart_transmit xb wt
+        /* UART_THR  transmit holding */
+        strb   \wt, [\xb, #UART_THR << EARLY_UART_REG_SHIFT]
+.endm
+
+/*
+ * Local variables:
+ * mode: ASM
+ * indent-tabs-mode: nil
+ * End:
+ */
-- 
1.7.10.4


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