[PATCH RFC 05/10] ARM: debug: Add Cortina Systems CS75xx UART0 support
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COOLING9d
From: Fil Dunsky via B4 Relay <devnull+filipp.dunsky.gmail.com@kernel.org>
Date: 2026-09-30 07:00:02
Also in:
b4-sent, linux-arm-kernel, linux-serial, lkml
Subsystem:
arm port, the rest · Maintainers:
Russell King, Linus Torvalds
From: Fil Dunsky <redacted> Add low-level debug output through UART0 of the Cortina Systems CS75xx SoCs. The UART is mapped at a fixed virtual address by the generic debug_ll_io_init(), so no platform map_io is needed. Signed-off-by: Fil Dunsky <redacted> --- arch/arm/Kconfig.debug | 16 ++++++++++++++-- arch/arm/include/debug/cs75xx.S | 36 ++++++++++++++++++++++++++++++++++++ 2 files changed, 50 insertions(+), 2 deletions(-)
diff --git a/arch/arm/Kconfig.debug b/arch/arm/Kconfig.debug
index abcf14f1027..61cd64fc152 100644
--- a/arch/arm/Kconfig.debug
+++ b/arch/arm/Kconfig.debug@@ -308,6 +308,15 @@ choice Say Y here if you want the debug print routines to direct their output to the second serial port on these devices. + config DEBUG_CS75XX_UART0 + bool "Kernel low-level debugging messages via CS75xx UART0" + depends on ARCH_CORTINA_CS75XX + help + Say Y here if you want the debug print routines to direct + their output to UART0 of Cortina Systems CS75xx SoCs. This + is the console port on the Securifi Almond+. The UART is + expected to be set up by the bootloader. + config DEBUG_DAVINCI_DA8XX_UART1 bool "Kernel low-level debugging on DaVinci DA8XX using UART1" depends on ARCH_DAVINCI_DA8XX
@@ -1531,6 +1540,7 @@ config DEBUG_LL_INCLUDE default "debug/vt8500.S" if DEBUG_VT8500_UART0 default "debug/zynq.S" if DEBUG_ZYNQ_UART0 || DEBUG_ZYNQ_UART1 default "debug/bcm63xx.S" if DEBUG_BCM63XX_UART || DEBUG_BCMBCA + default "debug/cs75xx.S" if DEBUG_CS75XX_UART0 default "debug/digicolor.S" if DEBUG_DIGICOLOR_UA0 default "debug/brcmstb.S" if DEBUG_BRCMSTB_UART default "mach/debug-macro.S"
@@ -1632,6 +1642,7 @@ config DEBUG_UART_PHYS default 0xe8008000 if DEBUG_R7S72100_SCIF2 || DEBUG_R7S9210_SCIF2 default 0xe8009000 if DEBUG_R7S9210_SCIF4 default 0xf0000000 if DEBUG_DIGICOLOR_UA0 + default 0xf0070110 if DEBUG_CS75XX_UART0 default 0xf1012000 if DEBUG_MVEBU_UART0_ALTERNATE default 0xf1012100 if DEBUG_MVEBU_UART1_ALTERNATE default 0xf7fc9000 if DEBUG_BERLIN_UART
@@ -1670,7 +1681,7 @@ config DEBUG_UART_PHYS DEBUG_RMOBILE_SCIFA4 || \ DEBUG_S3C64XX_UART || \ DEBUG_BCM63XX_UART || DEBUG_BCMBCA || DEBUG_ASM9260_UART || \ - DEBUG_DIGICOLOR_UA0 || \ + DEBUG_CS75XX_UART0 || DEBUG_DIGICOLOR_UA0 || \ DEBUG_AT91_UART || DEBUG_STM32_UART || \ DEBUG_STIH41X_ASC2 || DEBUG_STIH41X_SBC_ASC1 || \ DEBUG_STIH418_SBC_ASC0
@@ -1708,6 +1719,7 @@ config DEBUG_UART_VIRT default 0xf7000800 if DEBUG_S3C64XX_UART && DEBUG_S3C_UART2 default 0xf7000c00 if DEBUG_S3C64XX_UART && DEBUG_S3C_UART3 default 0xf7020000 if DEBUG_AT91_SAMA5D2_UART1 + default 0xf7070110 if DEBUG_CS75XX_UART0 default 0xf7fc9000 if DEBUG_BERLIN_UART default 0xf8007000 if DEBUG_HIP04_UART default 0xf8009000 if DEBUG_VEXPRESS_UART0_CA9
@@ -1772,7 +1784,7 @@ config DEBUG_UART_VIRT DEBUG_QCOM_UARTDM || \ DEBUG_S3C64XX_UART || \ DEBUG_BCM63XX_UART || DEBUG_BCMBCA || DEBUG_ASM9260_UART || \ - DEBUG_DIGICOLOR_UA0 || \ + DEBUG_CS75XX_UART0 || DEBUG_DIGICOLOR_UA0 || \ DEBUG_AT91_UART || DEBUG_STM32_UART || \ DEBUG_STIH41X_ASC2 || DEBUG_STIH41X_SBC_ASC1 || \ DEBUG_STIH418_SBC_ASC0
diff --git a/arch/arm/include/debug/cs75xx.S b/arch/arm/include/debug/cs75xx.S
new file mode 100644
index 00000000000..d840384cc32
--- /dev/null
+++ b/arch/arm/include/debug/cs75xx.S@@ -0,0 +1,36 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Debugging macro include header for the Cortina Systems CS75xx UART + */ + +#define CS75XX_UART_TXDAT 0x10 +#define CS75XX_UART_INFO 0x18 +#define CS75XX_UART_INFO_TX_FULL (1 << 2) +#define CS75XX_UART_INFO_TX_EMPTY (1 << 3) + + .macro addruart, rp, rv, tmp + ldr \rp, =CONFIG_DEBUG_UART_PHYS + ldr \rv, =CONFIG_DEBUG_UART_VIRT + .endm + + .macro senduart, rd, rx + ARM_BE8(rev \rd, \rd) + str \rd, [\rx, #CS75XX_UART_TXDAT] + .endm + + .macro waituartcts, rd, rx + .endm + + .macro waituarttxrdy, rd, rx +1001: ldr \rd, [\rx, #CS75XX_UART_INFO] + ARM_BE8(rev \rd, \rd) + tst \rd, #CS75XX_UART_INFO_TX_FULL + bne 1001b + .endm + + .macro busyuart, rd, rx +1002: ldr \rd, [\rx, #CS75XX_UART_INFO] + ARM_BE8(rev \rd, \rd) + tst \rd, #CS75XX_UART_INFO_TX_EMPTY + beq 1002b + .endm
--
2.53.0