Hi,
On 14/04/2019 18:50, Amit Singh Tomar wrote:
This patch adds earlyprintk support for Amlogic Meson SoC based
boards.
ATF[1] and U-boot[2] already initialize the UART for us. So no need to do it
again.
Tested With:
http://wiki.friendlyarm.com/wiki/index.php/NanoPi_K2
[1]:
https://github.com/ARM-software/arm-trusted-firmware/blob/master/drivers/meson/console/aarch64/meson_console.S#L92
[2]:
https://github.com/u-boot/u-boot/blob/master/drivers/serial/serial_meson.c#L44
Signed-off-by: Amit Singh Tomar <amittome...@gmail.com>
Acked-by: Julien Grall <julien.gr...@arm.com>
I have pushed to my branch next-4.13 for now. It will be merged once the commit
moratorium is lifted.
Cheers,
---
Changes since v3:
* Change the commit message to include firmware names.
Changes since v2:
* Added the commit message that talks about
uart initialization.
* Added dummy early_uart_init function.
Changes since v1:
* Fixed coding style issue.
* Undone changes in early-printk.txt.
Changes since RFC:
* Replaced LDRH with LDR, with this there
is no scattered output on console now.
* Used tbnz instead of tst and b.ne.
* Used AML_ prefix against register names.
---
xen/arch/arm/arm64/debug-meson.inc | 55 ++++++++++++++++++++++++++++++++++++++
1 file changed, 55 insertions(+)
create mode 100644 xen/arch/arm/arm64/debug-meson.inc
diff --git a/xen/arch/arm/arm64/debug-meson.inc
b/xen/arch/arm/arm64/debug-meson.inc
new file mode 100644
index 0000000..e1a8fa8
--- /dev/null
+++ b/xen/arch/arm/arm64/debug-meson.inc
@@ -0,0 +1,55 @@
+/*
+ * xen/arch/arm/arm64/debug-meson.inc
+ *
+ * MESON specific debug code.
+ *
+ * Copyright (c) 2019, Amit Singh Tomar <amittome...@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 AML_UART_WFIFO_REG 0x00
+#define AML_UART_STATUS_REG 0x0c
+
+#define AML_UART_TX_FIFO_FULL 21
+
+.macro early_uart_init xb, c
+/* Uart has already been initialized by Firmware, for instance by TF-A */
+.endm
+
+/*
+ * MESON 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, #AML_UART_STATUS_REG] /* status register */
+ tbnz w\c, #AML_UART_TX_FIFO_FULL, 1b /* Check TXFIFO FULL
bit */
+.endm
+
+/*
+ * MESON 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, #AML_UART_WFIFO_REG]
+.endm
+
+/*
+ * Local variables:
+ * mode: ASM
+ * indent-tabs-mode: nil
+ * End:
+ */
--
Julien Grall
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