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| author | Andre Przywara <andre.przywara@calxeda.com> | 2013-05-24 15:47:26 +0200 |
|---|---|---|
| committer | Ian Campbell <ian.campbell@citrix.com> | 2013-05-30 09:20:10 +0100 |
| commit | b68346247f74e002ef180403167888a03f488080 (patch) | |
| tree | 05b17aaa93f8ba4d5dfb6b8151cacab4b842dfb8 | |
| parent | 54353cae096c19f176417f6d425de0a0f8a71228 (diff) | |
| download | xen-b68346247f74e002ef180403167888a03f488080.tar.gz xen-b68346247f74e002ef180403167888a03f488080.tar.bz2 xen-b68346247f74e002ef180403167888a03f488080.zip | |
arm/early-printk: calculate baud rate divisor from user provided value
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>
Reviewed-by: Julien Grall <julien.grall@linaro.org>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
| -rw-r--r-- | docs/misc/arm/early-printk.txt | 3 | ||||
| -rw-r--r-- | xen/arch/arm/Rules.mk | 3 | ||||
| -rw-r--r-- | xen/arch/arm/arm32/debug-exynos4210.inc | 4 | ||||
| -rw-r--r-- | xen/arch/arm/arm32/debug-pl011.inc | 4 | ||||
| -rw-r--r-- | xen/arch/arm/arm64/debug-pl011.inc | 4 |
5 files changed, 12 insertions, 6 deletions
diff --git a/docs/misc/arm/early-printk.txt b/docs/misc/arm/early-printk.txt index d5cae85ddb..10c30531f6 100644 --- a/docs/misc/arm/early-printk.txt +++ b/docs/misc/arm/early-printk.txt @@ -12,4 +12,7 @@ where mach is the name of the machine: - vexpress: printk with pl011 for versatile express - exynos5250: printk with the second UART +The baud rate is hardcoded in xen/arch/arm/Rules.mk, +see there when adding support for new machines. + By default early printk is disabled. diff --git a/xen/arch/arm/Rules.mk b/xen/arch/arm/Rules.mk index b6a68902bb..b4d690716a 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 42416406ca..4922148ac1 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 6954aeb660..2d970ea364 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 ee6e0e03e7..722094036d 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) */ |