new file mode 100644
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+/*
+ * xen/arch/arm/arm64/debug-imx8mq.inc
+ *
+ * IMX8MQ specific debug code.
+ *
+ * Copyright (c) 2019, Amit Singh Tomar <amittomer25@gmail.com>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms and conditions of the GNU General Public
+ * License, version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#define UTXD 0x40
+#define UTS 0xb4
+#define UTS_TXEMPTY 3<<1
+
+.macro early_uart_init xb, c
+/* Uart has already been initialized by bootloader Firmware, for instance by TF-A */
+.endm
+
+/*
+ * IMX8MQ UART wait UART to be ready to transmit
+ * xb: register which contains the UART base address
+ * c: scratch register
+ */
+.macro early_uart_ready xb c
+1:
+ ldr w\c, [\xb, #UTS] /* UART Test Register */
+ tbz w\c, #UTS_TXEMPTY, 1b /* Check TXEMPTY bit */
+.endm
+
+/*
+ * IMX8MQ UART transmit character
+ * xb: register which contains the UART base address
+ * wt: register which contains the character to transmit
+ */
+.macro early_uart_transmit xb wt
+ str \wt, [\xb, #UTXD]
+.endm
+
+/*
+ * Local variables:
+ * mode: ASM
+ * indent-tabs-mode: nil
+ * End:
+ */
This patch adds earlyprintk support for i.MX8MQ SoC based boards. As with most of other debug code for other platforms, uart is initialized by bootloaders(for instance u-boot[1]). [1]:https://github.com/u-boot/u-boot/blob/master/drivers/serial/serial_mxc.c#L141 Signed-off-by: Amit Singh Tomar <amittomer25@gmail.com> --- xen/arch/arm/arm64/debug-imx8mq.inc | 54 +++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) create mode 100644 xen/arch/arm/arm64/debug-imx8mq.inc