diff options
| -rw-r--r-- | arch/arm/mach-tegra/include/mach/uncompress.h | 75 |
1 files changed, 74 insertions, 1 deletions
diff --git a/arch/arm/mach-tegra/include/mach/uncompress.h b/arch/arm/mach-tegra/include/mach/uncompress.h index bb3fd359f9fa..6c087b6974b2 100644 --- a/arch/arm/mach-tegra/include/mach/uncompress.h +++ b/arch/arm/mach-tegra/include/mach/uncompress.h @@ -3,11 +3,13 @@ * * Copyright (C) 2010 Google, Inc. * Copyright (C) 2011 Google, Inc. + * Copyright (C) 2011 NVIDIA CORPORATION. All Rights Reserved. * * Author: * Colin Cross <ccross@google.com> * Erik Gilling <konkers@google.com> * Doug Anderson <dianders@chromium.org> + * Stephen Warren <swarren@nvidia.com> * * This software is licensed under the terms of the GNU General Public * License version 2, as published by the Free Software Foundation, and @@ -23,6 +25,7 @@ #ifndef __MACH_TEGRA_UNCOMPRESS_H #define __MACH_TEGRA_UNCOMPRESS_H +#include <linux/kernel.h> #include <linux/types.h> #include <linux/serial_reg.h> @@ -46,12 +49,82 @@ static inline void flush(void) { } +/* + * Setup before decompression. This is where we do UART selection for + * earlyprintk and init the uart_base register. + */ static inline void arch_decomp_setup(void) { + static const struct { + u32 base; + u32 reset_reg; + u32 clock_reg; + u32 bit; + } uarts[] = { + { + TEGRA_UARTA_BASE, + TEGRA_CLK_RESET_BASE + 0x04, + TEGRA_CLK_RESET_BASE + 0x10, + 6, + }, + { + TEGRA_UARTB_BASE, + TEGRA_CLK_RESET_BASE + 0x04, + TEGRA_CLK_RESET_BASE + 0x10, + 7, + }, + { + TEGRA_UARTC_BASE, + TEGRA_CLK_RESET_BASE + 0x08, + TEGRA_CLK_RESET_BASE + 0x14, + 23, + }, + { + TEGRA_UARTD_BASE, + TEGRA_CLK_RESET_BASE + 0x0c, + TEGRA_CLK_RESET_BASE + 0x18, + 1, + }, + { + TEGRA_UARTE_BASE, + TEGRA_CLK_RESET_BASE + 0x0c, + TEGRA_CLK_RESET_BASE + 0x18, + 2, + }, + }; + int i; volatile u32 *apb_misc = (volatile u32 *)TEGRA_APB_MISC_BASE; u32 chip, div; - uart = (volatile u8 *)TEGRA_DEBUG_UART_BASE; + /* + * Look for the first UART that: + * a) Is not in reset. + * b) Is clocked. + * c) Has a 'D' in the scratchpad register. + * + * Note that on Tegra30, the first two conditions are required, since + * if not true, accesses to the UART scratch register will hang. + * Tegra20 doesn't have this issue. + * + * The intent is that the bootloader will tell the kernel which UART + * to use by setting up those conditions. If nothing found, we'll fall + * back to what's specified in TEGRA_DEBUG_UART_BASE. + */ + for (i = 0; i < ARRAY_SIZE(uarts); i++) { + if (*(u8 *)uarts[i].reset_reg & BIT(uarts[i].bit)) + continue; + + if (!(*(u8 *)uarts[i].clock_reg & BIT(uarts[i].bit))) + continue; + + uart = (volatile u8 *)uarts[i].base; + if (uart[UART_SCR << DEBUG_UART_SHIFT] != 'D') + continue; + + break; + } + if (i == ARRAY_SIZE(uarts)) + uart = (volatile u8 *)TEGRA_DEBUG_UART_BASE; if (uart == NULL) return; |