[PATCH v2 2/5] ARM: mstar: Add machine for MStar/Sigmastar infinity/mercury family ARMv7 SoCs

Daniel Palmer
2020-06-10T09:08:34Z

Initial support for the MStar/Sigmastar infinity/mercury series of ARMv7
based IP camera and dashcam SoCs.

These chips are interesting in that they contain a Cortex A7,
peripherals and system memory in a single tiny QFN package that
can be hand soldered allowing almost anyone to embed Linux
in their projects.

Signed-off-by: Daniel Palmer <daniel@0x0f.com>
---
MAINTAINERS | 1 +
arch/arm/Kconfig | 2 +
arch/arm/Makefile | 1 +
arch/arm/mach-mstar/Kconfig | 26 +++++++++++++
arch/arm/mach-mstar/Makefile | 1 +
arch/arm/mach-mstar/mstarv7.c | 72 +++++++++++++++++++++++++++++++++++
6 files changed, 103 insertions(+)
create mode 100644 arch/arm/mach-mstar/Kconfig
create mode 100644 arch/arm/mach-mstar/Makefile
create mode 100644 arch/arm/mach-mstar/mstarv7.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 1ca77f97b8ee..754521938303 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2114,6 +2114,7 @@ ARM/MStar/Sigmastar ARMv7 SoC support
M: Daniel Palmer <daniel@thingy.jp>
L: linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
S: Maintained
+F: arch/arm/mach-mstar/
F: Documentation/devicetree/bindings/arm/mstar.yaml

ARM/NEC MOBILEPRO 900/c MACHINE SUPPORT
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index fb6c85c5d344..e466694f8486 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -669,6 +669,8 @@ source "arch/arm/mach-mmp/Kconfig"

source "arch/arm/mach-moxart/Kconfig"

+source "arch/arm/mach-mstar/Kconfig"
+
source "arch/arm/mach-mv78xx0/Kconfig"

source "arch/arm/mach-mvebu/Kconfig"
diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index 59fde2d598d8..e7f4ca060c0f 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -197,6 +197,7 @@ machine-$(CONFIG_ARCH_MXC) += imx
machine-$(CONFIG_ARCH_MEDIATEK) += mediatek
machine-$(CONFIG_ARCH_MILBEAUT) += milbeaut
machine-$(CONFIG_ARCH_MXS) += mxs
+machine-$(CONFIG_ARCH_MSTARV7) += mstar
machine-$(CONFIG_ARCH_NOMADIK) += nomadik
machine-$(CONFIG_ARCH_NPCM) += npcm
machine-$(CONFIG_ARCH_NSPIRE) += nspire
diff --git a/arch/arm/mach-mstar/Kconfig b/arch/arm/mach-mstar/Kconfig
new file mode 100644
index 000000000000..6235d0a7860a
--- /dev/null
+++ b/arch/arm/mach-mstar/Kconfig
@@ -0,0 +1,26 @@
+menuconfig ARCH_MSTARV7
+ bool "MStar/Sigmastar ARMv7 SoC Support"
+ depends on ARCH_MULTI_V7
+ select ARM_GIC
+ select ARM_HEAVY_MB
+ help
+ Support for newer MStar/Sigmastar SoC families that are
+ based on ARMv7 cores like the Cortex A7 and share the same
+ basic hardware like the infinity and mercury series.
+
+if ARCH_MSTARV7
+
+config MACH_INFINITY
+ bool "MStar/Sigmastar infinity SoC support"
+ default ARCH_MSTARV7
+ help
+ Support for MStar/Sigmastar infinity IP camera SoCs.
+
+config MACH_MERCURY
+ bool "MStar/Sigmastar mercury SoC support"
+ default ARCH_MSTARV7
+ help
+ Support for MStar/Sigmastar mercury dash camera SoCs.
+ Note that older Mercury2 SoCs are ARM9 based and not supported.
+
+endif
diff --git a/arch/arm/mach-mstar/Makefile b/arch/arm/mach-mstar/Makefile
new file mode 100644
index 000000000000..93b0391ede7e
--- /dev/null
+++ b/arch/arm/mach-mstar/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_ARCH_MSTARV7) += mstarv7.o
diff --git a/arch/arm/mach-mstar/mstarv7.c b/arch/arm/mach-mstar/mstarv7.c
new file mode 100644
index 000000000000..ee96ce46cbbc
--- /dev/null
+++ b/arch/arm/mach-mstar/mstarv7.c
@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Device Tree support for MStar/Sigmastar ARMv7 SoCs
+ *
+ * Copyright (c) 2019 thingy.jp
+ * Author: Daniel Palmer <daniel@thingy.jp>
+ */
+
+#include <linux/init.h>
+#include <asm/mach/arch.h>
+#include <asm/mach/map.h>
+#include <linux/of.h>
+#include <linux/io.h>
+
+/*
+ * In the u-boot code the area these registers are in is
+ * called "L3 bridge" and there are register descriptions
+ * for something in the same area called "AXI".
+ *
+ * It's not exactly known what this is but the vendor code
+ * for both u-boot and linux share calls to "flush the miu pipe".
+ * This seems to be to force pending CPU writes to memory so that
+ * the state is right before DMA capable devices try to read
+ * descriptors and data the CPU has prepared. Without doing this
+ * ethernet doesn't work reliably for example.
+ */
+
+#define MSTARV7_L3BRIDGE_FLUSH 0x1f204414
+#define MSTARV7_L3BRIDGE_STATUS 0x1f204440
+#define MSTARV7_L3BRIDGE_FLUSH_TRIGGER BIT(0)
+#define MSTARV7_L3BRIDGE_STATUS_DONE BIT(12)
+
+static u32 __iomem *miu_status;
+static u32 __iomem *miu_flush;
+
+static const char * const mstarv7_board_dt_compat[] __initconst = {
+ "mstar,infinity",
+ "mstar,infinity3",
+ "mstar,mercury5",
+ NULL,
+};
+
+/*
+ * This may need locking to deal with situations where an interrupt
+ * happens while we are in here and mb() gets called by the interrupt handler.
+ */
+static void mstarv7_mb(void)
+{
+ /* toggle the flush miu pipe fire bit */
+ writel_relaxed(0, miu_flush);
+ writel_relaxed(MSTARV7_L3BRIDGE_FLUSH_TRIGGER, miu_flush);
+ while (!(readl_relaxed(miu_status) & MSTARV7_L3BRIDGE_STATUS_DONE)) {
+ /* wait for flush to complete */
+ }
+}
+
+static void __init mstarv7_barriers_init(void)
+{
+ miu_flush = ioremap(MSTARV7_L3BRIDGE_FLUSH, sizeof(*miu_flush));
+ miu_status = ioremap(MSTARV7_L3BRIDGE_STATUS, sizeof(*miu_status));
+ soc_mb = mstarv7_mb;
+}
+
+static void __init mstarv7_init(void)
+{
+ mstarv7_barriers_init();
+}
+
+DT_MACHINE_START(MSTARV7_DT, "MStar/Sigmastar ARMv7 (Device Tree)")
+ .dt_compat = mstarv7_board_dt_compat,
+ .init_machine = mstarv7_init,
+MACHINE_END
--
2.27.0.rc0