On Tegra20, the UART clock runs at 216MHz, whereas on Tegra30 it runs at 408MHz. Modify arch_decomp_setup() to detect Tegra20-vs-Tegra30 at run- time, and program the correct divisor.
This makes uncompressor messages work correctly on Tegra30. This also fixes early printk, assuming zImage is used and this setup code runs. v2: Use CHIPID register to differentiate between chips, rather than a GIC register. This should be more future-proof. Volatile is required to prevent the compiler transforming the 32-bit apb_misc register read into an 8-bit read of address 1 higher, since the HW only supports 32- bit accesses, and will hang on an 8-bit access. Signed-off-by: Stephen Warren <[email protected]> --- arch/arm/mach-tegra/include/mach/uncompress.h | 12 ++++++++++-- 1 files changed, 10 insertions(+), 2 deletions(-) diff --git a/arch/arm/mach-tegra/include/mach/uncompress.h b/arch/arm/mach-tegra/include/mach/uncompress.h index 4e83237..39bd5e5 100644 --- a/arch/arm/mach-tegra/include/mach/uncompress.h +++ b/arch/arm/mach-tegra/include/mach/uncompress.h @@ -45,15 +45,23 @@ static inline void flush(void) static inline void arch_decomp_setup(void) { + volatile u32 *apb_misc = (volatile u32 *)TEGRA_APB_MISC_BASE; + u32 chip, div; volatile u8 *uart = (volatile u8 *)TEGRA_DEBUG_UART_BASE; int shift = 2; if (uart == NULL) return; + chip = (apb_misc[0x804 / 4] >> 8) & 0xff; + if (chip == 0x20) + div = 0x0075; + else + div = 0x00dd; + uart[UART_LCR << shift] |= UART_LCR_DLAB; - uart[UART_DLL << shift] = 0x75; - uart[UART_DLM << shift] = 0x0; + uart[UART_DLL << shift] = div & 0xff; + uart[UART_DLM << shift] = div >> 8; uart[UART_LCR << shift] = 3; } -- 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
