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authorSerge Semin <Sergey.Semin@baikalelectronics.ru>2020-05-21 17:07:19 +0300
committerThomas Bogendoerfer <tsbogend@alpha.franken.de>2020-05-22 09:12:52 +0200
commitad42e0a8d4d5abd7243597b1a4f5ab4ede09f25a (patch)
tree7d1147652a430ffae621417ea13ffe41c5ab8858 /arch
parent999079c851b46fd945a8b074d115f9f08a056ca9 (diff)
downloadlinux-ad42e0a8d4d5abd7243597b1a4f5ab4ede09f25a.tar.bz2
mips: Add CPS_NS16550_WIDTH config
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@baikalelectronics.ru> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Paul Burton <paulburton@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: devicetree@vger.kernel.org Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Diffstat (limited to 'arch')
-rw-r--r--arch/mips/Kconfig.debug10
-rw-r--r--arch/mips/kernel/cps-vec-ns16550.S18
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)