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. Signed-off-by: Stephen Warren <[email protected]> --- arch/arm/mach-tegra/include/mach/uncompress.h | 20 ++++++++++++++++++-- 1 files changed, 18 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..61d6e08 100644 --- a/arch/arm/mach-tegra/include/mach/uncompress.h +++ b/arch/arm/mach-tegra/include/mach/uncompress.h @@ -24,6 +24,8 @@ #include <linux/types.h> #include <linux/serial_reg.h> +#include <asm/hardware/gic.h> + #include <mach/iomap.h> static void putc(int c) @@ -45,15 +47,29 @@ static inline void flush(void) static inline void arch_decomp_setup(void) { + u8 *distctr = (u8 *)(TEGRA_ARM_INT_DIST_BASE + + GIC_DIST_CTR); + u32 ctlrs, div; volatile u8 *uart = (volatile u8 *)TEGRA_DEBUG_UART_BASE; int shift = 2; if (uart == NULL) return; + /* + * Tegra20 has 4 interrupt controllers + * Tegra30 has 5 interrupt controllers + * Future SoCs may need additional means of identification + */ + ctlrs = (*distctr) & 0x1f; + if (ctlrs == 4) + 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
