From 19a7507a9e790841efe904647a2464425dcf5bb3 Mon Sep 17 00:00:00 2001
From: Andre Przywara <andre.przywara@arm.com>
Date: Sun, 4 Nov 2018 23:37:48 +0000
Subject: [PATCH] allwinner: A64/H5: setup missing bus clocks
The legacy Allwinner ATF port used to setup some clocks, and U-Boot is
still relying on this. We don't need to setup the full set, as the SPL
is doing most of it, but it misses one clock (AHB2) and programs another
(AHB1) to quite conservative values.
Fix this up during the platform setup to improve USB and Ethernet
performance, iperf values go up by 31% in my setup with that patch.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
plat/allwinner/common/sunxi_bl31_setup.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/plat/allwinner/common/sunxi_bl31_setup.c b/plat/allwinner/common/sunxi_bl31_setup.c
index 8f597c39e..2c6632912 100644
--- a/plat/allwinner/common/sunxi_bl31_setup.c
+++ b/plat/allwinner/common/sunxi_bl31_setup.c
@@ -11,6 +11,7 @@
#include <generic_delay_timer.h>
#include <gicv2.h>
#include <libfdt.h>
+#include <mmio.h>
#include <platform.h>
#include <platform_def.h>
#include <sunxi_def.h>
@@ -148,6 +149,25 @@ void bl31_platform_setup(void)
sunxi_security_setup();
+ /*
+ * On the A64 U-Boot's SPL sets the bus clocks to some conservative
+ * values, to work around FEL mode instabilities with SRAM C accesses.
+ * FEL mode is gone when we reach ATF, so bring the AHB1 bus
+ * (the "main" bus) clock frequency back to the recommended 200MHz,
+ * for improved performance.
+ */
+ if (soc_id == SUNXI_SOC_A64)
+ mmio_write_32(SUNXI_CCU_BASE + 0x54, 0x00003180);
+
+ /*
+ * U-Boot or the kernel don't setup AHB2, which leaves it at the
+ * AHB1 frequency (200 MHz, see above). However Allwinner recommends
+ * 300 MHz, for improved Ethernet and USB performance. Switch the
+ * clock to use "PLL_PERIPH0 / 2".
+ */
+ if (soc_id == SUNXI_SOC_A64 || soc_id == SUNXI_SOC_H5)
+ mmio_write_32(SUNXI_CCU_BASE + 0x5c, 0x1);
+
sunxi_pmic_setup(soc_id, fdt);
INFO("BL31: Platform setup done\n");
--
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