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Re: [PATCH 1/2] xen/arm: Add i.MX UART early printk support
On 03.04.24 13:11, Michal Orzel wrote:
Hi Oleksandr,
Hello Michal
sorry for the late response
On 02/04/2024 14:05, Oleksandr Tyshchenko wrote:
From: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
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).
Please use imperative mood in commit msg.
ok
I would mention also that you are adding
macros that will be used by the runtime driver.
will do
Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
---
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
Do not take example from surrounding code. help text should be indented by 2
tabs and 2 spaces here.
ok
+ 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 */
There is no need to surround these values
ok
+#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 */
NIT: please align comments within a block
ok
Other than that:
Reviewed-by: Michal Orzel <michal.orzel@xxxxxxx>
thanks
~Michal
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