From: Oleksandr Tyshchenko <oleksandr_tyshche...@epam.com>
Tested on i.MX 8M Mini only, but I guess, it should be
suitable for other i.MX8M* SoCs (those UART device tree nodes
contain "fsl,imx6q-uart" compatible string).
Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshche...@epam.com>
---
I selected the following configs for enabling early printk:
CONFIG_EARLY_UART_CHOICE_IMX_UART=y
CONFIG_EARLY_UART_IMX_UART=y
CONFIG_EARLY_PRINTK=y
CONFIG_EARLY_UART_BASE_ADDRESS=0x30890000
CONFIG_EARLY_PRINTK_INC="debug-imx-uart.inc"
---
---
xen/arch/arm/Kconfig.debug | 14 +++++
xen/arch/arm/arm64/debug-imx-uart.inc | 38 ++++++++++++++
xen/arch/arm/include/asm/imx-uart.h | 76 +++++++++++++++++++++++++++
3 files changed, 128 insertions(+)
create mode 100644 xen/arch/arm/arm64/debug-imx-uart.inc
create mode 100644 xen/arch/arm/include/asm/imx-uart.h
diff --git a/xen/arch/arm/Kconfig.debug b/xen/arch/arm/Kconfig.debug
index eec860e88e..a15d08f214 100644
--- a/xen/arch/arm/Kconfig.debug
+++ b/xen/arch/arm/Kconfig.debug
@@ -68,6 +68,16 @@ choice
provide the parameters for the i.MX LPUART rather than
selecting one of the platform specific options below if
you know the parameters for the port.
+ config EARLY_UART_CHOICE_IMX_UART
+ select EARLY_UART_IMX_UART
+ depends on ARM_64
+ bool "Early printk via i.MX UART"
+ help
+ Say Y here if you wish the early printk to direct their
+ output to a i.MX UART. You can use this option to
+ provide the parameters for the i.MX UART rather than
+ selecting one of the platform specific options below if
+ you know the parameters for the port.
config EARLY_UART_CHOICE_MESON
select EARLY_UART_MESON
depends on ARM_64
@@ -199,6 +209,9 @@ config EARLY_UART_EXYNOS4210
config EARLY_UART_IMX_LPUART
select EARLY_PRINTK
bool
+config EARLY_UART_IMX_UART
+ select EARLY_PRINTK
+ bool
config EARLY_UART_MESON
select EARLY_PRINTK
bool
@@ -304,6 +317,7 @@ config EARLY_PRINTK_INC
default "debug-cadence.inc" if EARLY_UART_CADENCE
default "debug-exynos4210.inc" if EARLY_UART_EXYNOS4210
default "debug-imx-lpuart.inc" if EARLY_UART_IMX_LPUART
+ default "debug-imx-uart.inc" if EARLY_UART_IMX_UART
default "debug-meson.inc" if EARLY_UART_MESON
default "debug-mvebu.inc" if EARLY_UART_MVEBU
default "debug-pl011.inc" if EARLY_UART_PL011
diff --git a/xen/arch/arm/arm64/debug-imx-uart.inc
b/xen/arch/arm/arm64/debug-imx-uart.inc
new file mode 100644
index 0000000000..27a68b1ed5
--- /dev/null
+++ b/xen/arch/arm/arm64/debug-imx-uart.inc
@@ -0,0 +1,38 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * xen/arch/arm/arm64/debug-imx-uart.inc
+ *
+ * i.MX8M* specific debug code
+ *
+ * Copyright (C) 2024 EPAM Systems Inc.
+ */
+
+#include <asm/imx-uart.h>
+
+/*
+ * Wait UART to be ready to transmit
+ * rb: register which contains the UART base address
+ * rc: scratch register
+ */
+.macro early_uart_ready xb, c
+1:
+ ldr w\c, [\xb, #IMX21_UTS] /* <- Test register */
+ tst w\c, #UTS_TXFULL /* Check TxFIFO FULL bit */
+ bne 1b /* Wait for the UART to be ready */
+.endm
+
+/*
+ * UART transmit character
+ * rb: register which contains the UART base address
+ * rt: register which contains the character to transmit
+ */
+.macro early_uart_transmit xb, wt
+ str \wt, [\xb, #URTX0] /* -> Transmitter Register */
+.endm
+
+/*
+ * Local variables:
+ * mode: ASM
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/arch/arm/include/asm/imx-uart.h
b/xen/arch/arm/include/asm/imx-uart.h
new file mode 100644
index 0000000000..413a81dd44
--- /dev/null
+++ b/xen/arch/arm/include/asm/imx-uart.h
@@ -0,0 +1,76 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * xen/arch/arm/include/asm/imx-uart.h
+ *
+ * Common constant definition between early printk and the UART driver
+ *
+ * Copyright (C) 2024 EPAM Systems Inc.
+ */
+
+#ifndef __ASM_ARM_IMX_UART_H__
+#define __ASM_ARM_IMX_UART_H__
+
+/* 32-bit register definition */
+#define URXD0 (0x00) /* Receiver Register */
+#define URTX0 (0x40) /* Transmitter Register */
+#define UCR1 (0x80) /* Control Register 1 */
+#define UCR2 (0x84) /* Control Register 2 */
+#define UCR3 (0x88) /* Control Register 3 */
+#define UCR4 (0x8c) /* Control Register 4 */
+#define UFCR (0x90) /* FIFO Control Register */
+#define USR1 (0x94) /* Status Register 1 */
+#define USR2 (0x98) /* Status Register 2 */
+#define IMX21_UTS (0xb4) /* Test Register */
+
+#define URXD_ERR BIT(14, UL) /* Error detect */
+#define URXD_RX_DATA GENMASK(7, 0) /* Received data mask */
+
+#define UCR1_TRDYEN BIT(13, UL) /* Transmitter ready interrupt enable */
+#define UCR1_RRDYEN BIT(9, UL) /* Receiver ready interrupt enable */
+#define UCR1_RXDMAEN BIT(8, UL) /* Receiver ready DMA enable */
+#define UCR1_TXMPTYEN BIT(6, UL) /* Transmitter empty interrupt enable */
+#define UCR1_RTSDEN BIT(5, UL) /* RTS delta interrupt enable */
+#define UCR1_TXDMAEN BIT(3, UL) /* Transmitter ready DMA enable */
+#define UCR1_ATDMAEN BIT(2, UL) /* Aging DMA Timer enable */
+#define UCR1_UARTEN BIT(0, UL) /* UART enable */
+
+#define UCR2_ATEN BIT(3, UL) /* Aging Timer Enable */
+#define UCR2_TXEN BIT(2, UL) /* Transmitter enable */
+#define UCR2_RXEN BIT(1, UL) /* Receiver enable */
+
+#define UCR4_TCEN BIT(3, UL) /* Transmit complete interrupt enable */
+#define UCR4_DREN BIT(0, UL) /* Receive data ready interrupt enable */
+
+#define UFCR_TXTL_SHF (10) /* Transmitter trigger level shift */
+#define UFCR_RFDIV GENMASK(9, 7) /* Reference frequency divider mask */
+#define UFCR_DCEDTE BIT(6, UL) /* DCE/DTE mode select */
+
+#define USR1_PARITYERR BIT(15, UL) /* Parity error interrupt flag */
+#define USR1_TRDY BIT(13, UL) /* Transmitter ready interrupt/DMA flag
*/
+#define USR1_FRAMERR BIT(10, UL) /* Frame error interrupt flag */
+#define USR1_RRDY BIT(9, UL) /* Receiver ready interrupt/DMA flag */
+#define USR1_AGTIM BIT(8, UL) /* Aging timer interrupt flag */
+
+#define USR2_TXDC BIT(3, UL) /* Transmitter complete */
+#define USR2_BRCD BIT(2, UL) /* Break condition detected */
+#define USR2_ORE BIT(1, UL) /* Overrun error */
+#define USR2_RDR BIT(0, UL) /* Receive data ready */
+
+#define UTS_TXEMPTY BIT(6, UL) /* TxFIFO empty */
+#define UTS_TXFULL BIT(4, UL) /* TxFIFO full */
+
+#define TXTL_DEFAULT (2)
+#define RXTL_DEFAULT (8)
+
+#define TX_FIFO_SIZE 32
+
+#endif /* __ASM_ARM_IMX_UART_H__ */
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
--
2.34.1
