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authorStephen Warren <swarren@nvidia.com>2013-11-06 01:10:53 +0400
committerStephen Warren <swarren@nvidia.com>2013-12-04 23:25:22 +0400
commit2f1d70af28a94988c1e8fba2ae03d4c7e68e690b (patch)
treee64da72f581414009ff50c27591483def90c3e05 /arch/arm/include/debug/tegra.S
parent354935a9e804878ec64a86ad8b7f091d544dcb54 (diff)
downloadlinux-2f1d70af28a94988c1e8fba2ae03d4c7e68e690b.tar.xz
ARM: tegra: don't hard-code DEBUG_LL baud rate
Stop writing to the UART clock divider registers in the Tegra DEBUG_LL code. This allows the DEBUG_LL output to use whatever baud rate was set up by the bootloader. Some users are using higher rates than 115200. This removes the only usage of tegra_uart_config[3], so reduce the size allocated for that array. Finally, fix busyuart() so that it only waits for THRE and not TEMT. For some reason, TEMT doesn't get asserted (at least on Tegra30 Beaver) at 9600 baud, even though it does at 115200 baud. This sounds like a HW bug, but I haven't investigated. For reference, U-Boot's serial code has always only checked THRE, and not checked TEMT. Signed-off-by: Stephen Warren <swarren@nvidia.com> Tested-by: Paul Walmsley <pwalmsley@nvidia.com> Reviewed-by: Thierry Reding <treding@nvidia.com>
Diffstat (limited to 'arch/arm/include/debug/tegra.S')
-rw-r--r--arch/arm/include/debug/tegra.S30
1 files changed, 3 insertions, 27 deletions
diff --git a/arch/arm/include/debug/tegra.S b/arch/arm/include/debug/tegra.S
index a7b7cedef1a6..f98763f0bc17 100644
--- a/arch/arm/include/debug/tegra.S
+++ b/arch/arm/include/debug/tegra.S
@@ -156,28 +156,6 @@
92: and \rv, \rp, #0xffffff @ offset within 1MB section
add \rv, \rv, #UART_VIRTUAL_BASE
str \rv, [\tmp, #8] @ Store in tegra_uart_virt
- movw \rv, #TEGRA_APB_MISC_GP_HIDREV & 0xffff
- movt \rv, #TEGRA_APB_MISC_GP_HIDREV >> 16
- ldr \rv, [\rv, #0] @ Load HIDREV
- ubfx \rv, \rv, #8, #8 @ 15:8 are SoC version
- cmp \rv, #0x20 @ Tegra20?
- moveq \rv, #0x75 @ Tegra20 divisor
- movne \rv, #0xdd @ Tegra30 divisor
- str \rv, [\tmp, #12] @ Save divisor to scratch
- /* uart[UART_LCR] = UART_LCR_WLEN8 | UART_LCR_DLAB; */
- mov \rv, #UART_LCR_WLEN8 | UART_LCR_DLAB
- str \rv, [\rp, #UART_LCR << UART_SHIFT]
- /* uart[UART_DLL] = div & 0xff; */
- ldr \rv, [\tmp, #12]
- and \rv, \rv, #0xff
- str \rv, [\rp, #UART_DLL << UART_SHIFT]
- /* uart[UART_DLM] = div >> 8; */
- ldr \rv, [\tmp, #12]
- lsr \rv, \rv, #8
- str \rv, [\rp, #UART_DLM << UART_SHIFT]
- /* uart[UART_LCR] = UART_LCR_WLEN8; */
- mov \rv, #UART_LCR_WLEN8
- str \rv, [\rp, #UART_LCR << UART_SHIFT]
b 100f
.align
@@ -205,8 +183,8 @@
cmp \rx, #0
beq 1002f
1001: ldrb \rd, [\rx, #UART_LSR << UART_SHIFT]
- and \rd, \rd, #UART_LSR_TEMT | UART_LSR_THRE
- teq \rd, #UART_LSR_TEMT | UART_LSR_THRE
+ and \rd, \rd, #UART_LSR_THRE
+ teq \rd, #UART_LSR_THRE
bne 1001b
1002:
.endm
@@ -225,7 +203,7 @@
/*
* Storage for the state maintained by the macros above.
*
- * In the kernel proper, this data is located in arch/arm/mach-tegra/common.c.
+ * In the kernel proper, this data is located in arch/arm/mach-tegra/tegra.c.
* That's because this header is included from multiple files, and we only
* want a single copy of the data. In particular, the UART probing code above
* assumes it's running using physical addresses. This is true when this file
@@ -247,6 +225,4 @@ tegra_uart_config:
.word 0
/* Debug UART virtual address */
.word 0
- /* Scratch space for debug macro */
- .word 0
#endif