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ARM: tegra: don't hard-code DEBUG_LL baud rate

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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>
This commit is contained in:
Stephen Warren 2013-11-05 14:10:53 -07:00
parent 354935a9e8
commit 2f1d70af28
2 changed files with 4 additions and 30 deletions
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30
arch/arm/include/debug/tegra.S
View File

@ -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

4
arch/arm/mach-tegra/tegra.c
View File

@ -60,15 +60,13 @@
* kernel is loaded. The data is declared here rather than debug-macro.S so
* that multiple inclusions of debug-macro.S point at the same data.
*/
u32 tegra_uart_config[4] = {
u32 tegra_uart_config[3] = {
/* Debug UART initialization required */
1,
/* Debug UART physical address */
0,
/* Debug UART virtual address */
0,
/* Scratch space for debug macro */
0,
};
static void __init tegra_init_cache(void)