uncompress.h now saves the selected UART's physical address in Tegra's IRAM, along with a cookie to indicate validity.
The first time it's run, macro addruart in debug-macro.S looks for this cookie, and if it's present, uses the UART address stored there. If not, the static value TEGRA_DEBUG_UART_BASE is used, as was previous behaviour. The static behaviour will thus be used when not booting using a zImage. This work was inspired by work by Doug Anderson <[email protected]>; see http://lkml.org/lkml/2011/9/26/284. However, this patch relies on the data passing describe above, rather than duplicating the UART selection logic in debug-macro.S; the latest selection logic is more complex due to the need to check reset/clock bits too. Signed-off-by: Stephen Warren <[email protected]> --- arch/arm/mach-tegra/common.c | 17 +++++ arch/arm/mach-tegra/include/mach/debug-macro.S | 87 +++++++++++++++++++++--- arch/arm/mach-tegra/include/mach/uncompress.h | 12 +++ 3 files changed, 105 insertions(+), 11 deletions(-) diff --git a/arch/arm/mach-tegra/common.c b/arch/arm/mach-tegra/common.c index a2eb901..76210e5 100644 --- a/arch/arm/mach-tegra/common.c +++ b/arch/arm/mach-tegra/common.c @@ -33,6 +33,23 @@ #include "clock.h" #include "fuse.h" +/* + * Storage for debug-macro.S's state. + * + * This must be in .data not .bss so that it gets initialized each time the + * 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. + */ +#define TEGRA_DEBUG_UART_OFFSET (TEGRA_DEBUG_UART_BASE & 0xFFFF) +u32 tegra_uart_config[3] = { + /* Debug UART initialization required */ + 1, + /* Debug UART physical address */ + (u32)(IO_APB_PHYS + TEGRA_DEBUG_UART_OFFSET), + /* Debug UART virtual address */ + (u32)(IO_APB_VIRT + TEGRA_DEBUG_UART_OFFSET), +}; + #ifdef CONFIG_OF static const struct of_device_id tegra_dt_irq_match[] __initconst = { { .compatible = "arm,cortex-a9-gic", .data = gic_of_init }, diff --git a/arch/arm/mach-tegra/include/mach/debug-macro.S b/arch/arm/mach-tegra/include/mach/debug-macro.S index 619abc6..94802a5 100644 --- a/arch/arm/mach-tegra/include/mach/debug-macro.S +++ b/arch/arm/mach-tegra/include/mach/debug-macro.S @@ -1,11 +1,17 @@ /* * arch/arm/mach-tegra/include/mach/debug-macro.S * - * Copyright (C) 2010 Google, Inc. + * Copyright (C) 2010,2011 Google, Inc. + * Copyright (C) 2011 NVIDIA CORPORATION. All Rights Reserved. * * Author: * Colin Cross <[email protected]> * Erik Gilling <[email protected]> + * Doug Anderson <[email protected]> + * Stephen Warren <[email protected]> + * + * Portions based on mach-omap2's debug-macro.S + * Copyright (C) 1994-1999 Russell King * * This software is licensed under the terms of the GNU General Public * License version 2, as published by the Free Software Foundation, and @@ -18,18 +24,77 @@ * */ +#include <linux/serial_reg.h> + #include <mach/io.h> #include <mach/iomap.h> - .macro addruart, rp, rv, tmp - ldr \rp, =IO_APB_PHYS @ physical - ldr \rv, =IO_APB_VIRT @ virtual - orr \rp, \rp, #(TEGRA_DEBUG_UART_BASE & 0xFF) - orr \rp, \rp, #(TEGRA_DEBUG_UART_BASE & 0xFF00) - orr \rv, \rv, #(TEGRA_DEBUG_UART_BASE & 0xFF) - orr \rv, \rv, #(TEGRA_DEBUG_UART_BASE & 0xFF00) - .endm + .macro addruart, rp, rv, tmp + adr \rp, 99f @ actual addr of 99f + ldr \rv, [\rp] @ linked addr is stored there + sub \rv, \rv, \rp @ offset between the two + ldr \rp, [\rp, #4] @ linked tegra_uart_config + sub \tmp, \rp, \rv @ actual tegra_uart_config + ldr \rp, [\tmp] @ Load tegra_uart_config + cmp \rp, #1 @ needs intitialization? + bne 100f @ no; go load the addresses + mov \rv, #0 @ yes; record init is done + str \rv, [\tmp] + mov \rp, #TEGRA_IRAM_BASE @ See if cookie is in IRAM + ldr \rv, [\rp, #0x100] + movw \rp, #0x5254 @ "UART" + movt \rp, #0x5541 + cmp \rv, \rp @ Cookie present? + bne 100f @ No, use default UART + mov \rp, #TEGRA_IRAM_BASE @ Load UART address from IRAM + ldr \rv, [\rp, #0x104] + str \rv, [\tmp, #4] @ Store in tegra_uart_phys + sub \rv, \rv, #IO_APB_PHYS @ Calculate virt address + add \rv, \rv, #IO_APB_VIRT + str \rv, [\tmp, #8] @ Store in tegra_uart_virt + b 100f + + .align +99: .word . + .word tegra_uart_config + .ltorg + +100: ldr \rp, [\tmp, #4] @ Load tegra_uart_phys + ldr \rv, [\tmp, #8] @ Load tegra_uart_virt + .endm + +#define UART_SHIFT 2 + +/* + * Code below is swiped from <asm/hardware/debug-8250.S>, but add an extra + * check to make sure that we aren't in the CONFIG_TEGRA_DEBUG_UART_NONE case. + * We use the fact that all 5 valid UART addresses all have something in the + * 2nd-to-lowest byte. + */ + + .macro senduart, rd, rx + tst \rx, #0x0000ff00 + strneb \rd, [\rx, #UART_TX << UART_SHIFT] +1001: + .endm -#define UART_SHIFT 2 -#include <asm/hardware/debug-8250.S> + .macro busyuart, rd, rx + tst \rx, #0x0000ff00 + 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 + bne 1001b +1002: + .endm + .macro waituart, rd, rx +#ifdef FLOW_CONTROL + tst \rx, #0x0000ff00 + beq 1002f +1001: ldrb \rd, [\rx, #UART_MSR << UART_SHIFT] + tst \rd, #UART_MSR_CTS + beq 1001b +1002: +#endif + .endm diff --git a/arch/arm/mach-tegra/include/mach/uncompress.h b/arch/arm/mach-tegra/include/mach/uncompress.h index 4d8e1b7..6bcb2bd 100644 --- a/arch/arm/mach-tegra/include/mach/uncompress.h +++ b/arch/arm/mach-tegra/include/mach/uncompress.h @@ -48,6 +48,17 @@ static inline void flush(void) { } +static inline void save_uart_address(void) +{ + u32 *iram = (u32 *)(TEGRA_IRAM_BASE + 0x100); + + if (uart) { + iram[0] = 0x55415254; /* "UART" */ + iram[1] = (u32)uart; + } else + iram[0] = 0; +} + /* * Setup before decompression. This is where we do UART selection for * earlyprintk and init the uart_base register. @@ -124,6 +135,7 @@ static inline void arch_decomp_setup(void) } if (i == ARRAY_SIZE(uarts)) uart = (volatile u8 *)TEGRA_DEBUG_UART_BASE; + save_uart_address(); if (uart == NULL) return; -- 1.7.0.4 -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
