From 2f1d70af28a94988c1e8fba2ae03d4c7e68e690b Mon Sep 17 00:00:00 2001 From: Stephen Warren Date: Tue, 5 Nov 2013 14:10:53 -0700 Subject: [PATCH] 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 Tested-by: Paul Walmsley Reviewed-by: Thierry Reding --- arch/arm/include/debug/tegra.S | 30 +++--------------------------- arch/arm/mach-tegra/tegra.c | 4 +--- 2 files changed, 4 insertions(+), 30 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 diff --git a/arch/arm/mach-tegra/tegra.c b/arch/arm/mach-tegra/tegra.c index 73368176c6e8..ea14d380fc0c 100644 --- a/arch/arm/mach-tegra/tegra.c +++ b/arch/arm/mach-tegra/tegra.c @@ -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)