On some platforms IO-memory might require to use a proper load/store instructions (like Baikal-T1 IO-memory). To fix the cps-vec UART debug printout let's add the CONFIG_CPS_NS16550_WIDTH config to determine which instructions lb/sb, lh/sh or lw/sw are required for MMIO operations. Signed-off-by: Serge Semin <Sergey.Semin@xxxxxxxxxxxxxxxxxxxx> Cc: Alexey Malahov <Alexey.Malahov@xxxxxxxxxxxxxxxxxxxx> Cc: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx> Cc: Paul Burton <paulburton@xxxxxxxxxx> Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx> Cc: Arnd Bergmann <arnd@xxxxxxxx> Cc: Rob Herring <robh+dt@xxxxxxxxxx> Cc: devicetree@xxxxxxxxxxxxxxx --- There might be another problem in cps-vec-ns16550.S connected with the difference in CPU/devices endinanness on some platforms. But there is no such for Baikal-T1 SoC. Changelog v3: - Introduce new CPS_NS16550_WIDTH to determine the IO access instrctions instead of using the CPS_NS16550_OFFSET config. --- arch/mips/Kconfig.debug | 10 ++++++++++ arch/mips/kernel/cps-vec-ns16550.S | 18 ++++++++++++++++-- 2 files changed, 26 insertions(+), 2 deletions(-) diff --git a/arch/mips/Kconfig.debug b/arch/mips/Kconfig.debug index 93a2974d2ab7..7a8d94cdd493 100644 --- a/arch/mips/Kconfig.debug +++ b/arch/mips/Kconfig.debug @@ -148,4 +148,14 @@ config MIPS_CPS_NS16550_SHIFT form their addresses. That is, log base 2 of the span between adjacent ns16550 registers in the system. +config MIPS_CPS_NS16550_WIDTH + int "UART Register Width" + default 1 + help + ns16550 registers width. UART registers IO access methods will be + selected in accordance with this parameter. By setting it to 1, 2 or + 4 UART registers will be accessed by means of lb/sb, lh/sh or lw/sw + instructions respectively. Any value not from that set activates + lb/sb instructions. + endif # MIPS_CPS_NS16550_BOOL diff --git a/arch/mips/kernel/cps-vec-ns16550.S b/arch/mips/kernel/cps-vec-ns16550.S index d5a67b4ce9f6..30725e1df987 100644 --- a/arch/mips/kernel/cps-vec-ns16550.S +++ b/arch/mips/kernel/cps-vec-ns16550.S @@ -14,16 +14,30 @@ #define UART_TX_OFS (UART_TX << CONFIG_MIPS_CPS_NS16550_SHIFT) #define UART_LSR_OFS (UART_LSR << CONFIG_MIPS_CPS_NS16550_SHIFT) +#if CONFIG_MIPS_CPS_NS16550_WIDTH == 1 +# define UART_L lb +# define UART_S sb +#elif CONFIG_MIPS_CPS_NS16550_WIDTH == 2 +# define UART_L lh +# define UART_S sh +#elif CONFIG_MIPS_CPS_NS16550_WIDTH == 4 +# define UART_L lw +# define UART_S sw +#else +# define UART_L lb +# define UART_S sb +#endif + /** * _mips_cps_putc() - write a character to the UART * @a0: ASCII character to write * @t9: UART base address */ LEAF(_mips_cps_putc) -1: lw t0, UART_LSR_OFS(t9) +1: UART_L t0, UART_LSR_OFS(t9) andi t0, t0, UART_LSR_TEMT beqz t0, 1b - sb a0, UART_TX_OFS(t9) + UART_S a0, UART_TX_OFS(t9) jr ra END(_mips_cps_putc) -- 2.25.1
