For some platforms such as Qualcomm we need to wait for the UART to be ready before writing characters to the UART in the same manner as the macro in debug.S used with the main "Uncompressing Linux ..." text. Pass an extra temporary variable to writeb and make it call waituarttxrdy and busyuart just like the other decomression messages. Optionally it will also call waituartcts if and only if CONFIG_DEBUG_UART_FLOW_CONTROL is selected. After this the decompression debug messages work fine on Qualcomm platforms if you compile head.S with -DDEBUG. Cc: Nicolas Pitre <nico@xxxxxxxxxxx> Cc: Fabrizio Castro <fabrizio.castro@xxxxxxxxxxxxxx> Cc: Ard Biesheuvel <ardb@xxxxxxxxxx> Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx> --- arch/arm/boot/compressed/head.S | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S index ba121eea9468..5c9c6fe590cb 100644 --- a/arch/arm/boot/compressed/head.S +++ b/arch/arm/boot/compressed/head.S @@ -28,19 +28,19 @@ #if defined(CONFIG_CPU_V6) || defined(CONFIG_CPU_V6K) || defined(CONFIG_CPU_V7) .macro loadsp, rb, tmp1, tmp2 .endm - .macro writeb, ch, rb + .macro writeb, ch, rb, tmp mcr p14, 0, \ch, c0, c5, 0 .endm #elif defined(CONFIG_CPU_XSCALE) .macro loadsp, rb, tmp1, tmp2 .endm - .macro writeb, ch, rb + .macro writeb, ch, rb, tmp mcr p14, 0, \ch, c8, c0, 0 .endm #else .macro loadsp, rb, tmp1, tmp2 .endm - .macro writeb, ch, rb + .macro writeb, ch, rb, tmp mcr p14, 0, \ch, c1, c0, 0 .endm #endif @@ -49,8 +49,13 @@ #include CONFIG_DEBUG_LL_INCLUDE - .macro writeb, ch, rb + .macro writeb, ch, rb, tmp +#ifdef CONFIG_DEBUG_UART_FLOW_CONTROL + waituartcts \tmp, \rb +#endif + waituarttxrdy \tmp, \rb senduart \ch, \rb + busyuart \tmp, \rb .endm #if defined(CONFIG_ARCH_SA1100) @@ -1326,7 +1331,7 @@ puts: loadsp r3, r2, r1 1: ldrb r2, [r0], #1 teq r2, #0 moveq pc, lr -2: writeb r2, r3 +2: writeb r2, r3, r1 mov r1, #0x00020000 3: subs r1, r1, #1 bne 3b -- 2.26.2
