From: H Hartley Sweeten Date: Sat, 16 Mar 2013 00:16:52 +0000 (-0500) Subject: ARM: ep93xx: Fix wait for UART FIFO to be empty X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=605c357bb40ce412c086f3a928d07c1d4349b95b;p=linux-beck.git ARM: ep93xx: Fix wait for UART FIFO to be empty Commit 210dce5f "ARM: ep93xx: properly wait for UART FIFO to be empty" Removed the timeout loop while waiting for the uart transmit fifo to empty. Some bootloaders leave the uart in a state where there might be bytes in the uart that are not transmitted when execution is handed over to the kernel. This results in a deadlocked system while waiting for the fifo to empty. Add back the timeout wait to prevent the deadlock. Increase the wait time to hopefully prevent the decompressor corruption that lead to commit 210dce5f. This corruption was probably due to a slow uart baudrate. The 10* increase in the wait time should be enough for all cases. Signed-off-by: H Hartley Sweeten Acked-by: Florian Fainelli Signed-off-by: Ryan Mallon --- diff --git a/arch/arm/mach-ep93xx/include/mach/uncompress.h b/arch/arm/mach-ep93xx/include/mach/uncompress.h index d2afb4dd82ab..b5cc77d2380b 100644 --- a/arch/arm/mach-ep93xx/include/mach/uncompress.h +++ b/arch/arm/mach-ep93xx/include/mach/uncompress.h @@ -47,9 +47,13 @@ static void __raw_writel(unsigned int value, unsigned int ptr) static inline void putc(int c) { - /* Transmit fifo not full? */ - while (__raw_readb(PHYS_UART_FLAG) & UART_FLAG_TXFF) - ; + int i; + + for (i = 0; i < 10000; i++) { + /* Transmit fifo not full? */ + if (!(__raw_readb(PHYS_UART_FLAG) & UART_FLAG_TXFF)) + break; + } __raw_writeb(c, PHYS_UART_DATA); }