From: Andre Przywara <andre.przywara@calxeda.com>
To: stefano.stabellini@eu.citrix.com, Ian.Campbell@citrix.com
Cc: Andre Przywara <andre.przywara@calxeda.com>, xen-devel@lists.xen.org
Subject: [PATCH 1/4] arm/early-printk: calculate baud rate divisor from user provided value
Date: Fri, 24 May 2013 12:42:29 +0200 [thread overview]
Message-ID: <1369392152-1305-2-git-send-email-andre.przywara@calxeda.com> (raw)
In-Reply-To: <1369392152-1305-1-git-send-email-andre.przywara@calxeda.com>
For early-printk the used baud rate was hardcoded in the code, using
precalculated divisor values.
Let the calculation of these values be done by the preprocessor and
use a human readable value in xen/arch/arm/Rules.mk to drive this.
Signed-off-by: Andre Przywara <andre.przywara@calxeda.com>
---
xen/arch/arm/Rules.mk | 3 +++
xen/arch/arm/arm32/debug-exynos4210.inc | 4 ++--
xen/arch/arm/arm32/debug-pl011.inc | 4 ++--
xen/arch/arm/arm64/debug-pl011.inc | 4 ++--
4 files changed, 9 insertions(+), 6 deletions(-)
diff --git a/xen/arch/arm/Rules.mk b/xen/arch/arm/Rules.mk
index b6a6890..b4d6907 100644
--- a/xen/arch/arm/Rules.mk
+++ b/xen/arch/arm/Rules.mk
@@ -45,9 +45,11 @@ ifeq ($(debug),y)
# TODO handle UART base address from make command line
ifeq ($(CONFIG_EARLY_PRINTK), vexpress)
EARLY_PRINTK_INC := pl011
+EARLY_PRINTK_BAUD := 38400
endif
ifeq ($(CONFIG_EARLY_PRINTK), exynos5250)
EARLY_PRINTK_INC := exynos4210
+EARLY_PRINTK_BAUD := 115200
endif
ifneq ($(EARLY_PRINTK_INC),)
@@ -56,4 +58,5 @@ endif
CFLAGS-$(EARLY_PRINTK) += -DEARLY_PRINTK
CFLAGS-$(EARLY_PRINTK) += -DEARLY_PRINTK_INC=\"debug-$(EARLY_PRINTK_INC).inc\"
+CFLAGS-$(EARLY_PRINTK) += -DEARLY_PRINTK_BAUD=$(EARLY_PRINTK_BAUD)
endif
diff --git a/xen/arch/arm/arm32/debug-exynos4210.inc b/xen/arch/arm/arm32/debug-exynos4210.inc
index 4241640..4922148 100644
--- a/xen/arch/arm/arm32/debug-exynos4210.inc
+++ b/xen/arch/arm/arm32/debug-exynos4210.inc
@@ -38,9 +38,9 @@
orr \rd, \rd, #(0x7<<8)
str \rd, [\rc, #0x558]
- mov \rc, #4
+ mov \rc, #(100000000 / EARLY_PRINTK_BAUD % 16)
str \rc, [\rb, #UFRACVAL] /* -> UFRACVAL (Baud divisor fraction) */
- mov \rc, #53
+ mov \rc, #(100000000 / EARLY_PRINTK_BAUD / 16 - 1)
str \rc, [\rb, #UBRDIV] /* -> UBRDIV (Baud divisor integer) */
mov \rc, #3 /* 8n1 */
str \rc, [\rb, #ULCON] /* -> (Line control) */
diff --git a/xen/arch/arm/arm32/debug-pl011.inc b/xen/arch/arm/arm32/debug-pl011.inc
index 6954aeb..2d970ea 100644
--- a/xen/arch/arm/arm32/debug-pl011.inc
+++ b/xen/arch/arm/arm32/debug-pl011.inc
@@ -23,9 +23,9 @@
* rc: scratch register 1
* rd: scratch register 2 (unused here) */
.macro early_uart_init rb, rc, rd
- mov \rc, #0x0
+ mov \rc, #(7372800 / EARLY_PRINTK_BAUD % 16)
str \rc, [\rb, #0x28] /* -> UARTFBRD (Baud divisor fraction) */
- mov \rc, #0x4 /* 7.3728MHz / 0x4 == 16 * 115200 */
+ mov \rc, #(7372800 / EARLY_PRINTK_BAUD / 16)
str \rc, [\rb, #0x24] /* -> UARTIBRD (Baud divisor integer) */
mov \rc, #0x60 /* 8n1 */
str \rc, [\rb, #0x2C] /* -> UARTLCR_H (Line control) */
diff --git a/xen/arch/arm/arm64/debug-pl011.inc b/xen/arch/arm/arm64/debug-pl011.inc
index ee6e0e0..7220940 100644
--- a/xen/arch/arm/arm64/debug-pl011.inc
+++ b/xen/arch/arm/arm64/debug-pl011.inc
@@ -24,9 +24,9 @@
* xb: register which containts the UART base address
* c: scratch register number */
.macro early_uart_init xb, c
- mov x\c, #0x0
+ mov x\c, #(7372800 / EARLY_PRINTK_BAUD % 16)
strh w\c, [\xb, #0x28] /* -> UARTFBRD (Baud divisor fraction) */
- mov x\c, #0x4 /* 7.3728MHz / 0x4 == 16 * 115200 */
+ mov x\c, #(7372800 / EARLY_PRINTK_BAUD / 16)
strh w\c, [\xb, #0x24] /* -> UARTIBRD (Baud divisor integer) */
mov x\c, #0x60 /* 8n1 */
str w\c, [\xb, #0x2C] /* -> UARTLCR_H (Line control) */
--
1.7.12.1
next prev parent reply other threads:[~2013-05-24 10:42 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-24 10:42 [PATCH 0/4] ARM/early-printk: Improve reusability and add Calxeda support Andre Przywara
2013-05-24 10:42 ` Andre Przywara [this message]
2013-05-24 12:15 ` [PATCH 1/4] arm/early-printk: calculate baud rate divisor from user provided value Julien Grall
2013-05-24 10:42 ` [PATCH 2/4] arm/early-printk: allow skipping of UART init Andre Przywara
2013-05-24 12:30 ` Julien Grall
2013-05-24 10:42 ` [PATCH 3/4] arm/early-printk: move UART base address to Rules.mk Andre Przywara
2013-05-24 12:36 ` Julien Grall
2013-05-24 12:51 ` Julien Grall
2013-05-24 10:42 ` [PATCH 4/4] arm/early-printk: add Calxeda Midway UART support Andre Przywara
2013-05-24 12:38 ` Julien Grall
2013-05-24 12:40 ` [PATCH 0/4] ARM/early-printk: Improve reusability and add Calxeda support Julien Grall
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