[U-Boot] [PATCH v3 1/2] x86: Add SCU IPC driver for Intel MID platforms
Andy Shevchenko
andriy.shevchenko at linux.intel.com
Sat Apr 1 13:21:33 UTC 2017
From: Felipe Balbi <felipe.balbi at linux.intel.com>
Intel MID platforms have few microcontrollers inside SoC, one of them
is so called System Controller Unit (SCU).
Here is the driver to communicate with microcontroller.
Signed-off-by: Vincent Tinelli <vincent.tinelli at intel.com>
Signed-off-by: Felipe Balbi <felipe.balbi at linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko at linux.intel.com>
---
arch/x86/Kconfig | 2 +
arch/x86/include/asm/cpu.h | 1 +
arch/x86/include/asm/scu.h | 28 ++++++++
arch/x86/lib/Makefile | 1 +
arch/x86/lib/scu.c | 168 +++++++++++++++++++++++++++++++++++++++++++++
5 files changed, 200 insertions(+)
create mode 100644 arch/x86/include/asm/scu.h
create mode 100644 arch/x86/lib/scu.c
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index dfdd7564ea..9a1ecd7907 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -83,6 +83,8 @@ endchoice
# subarchitectures-specific options below
config INTEL_MID
bool "Intel MID platform support"
+ select REGMAP
+ select SYSCON
help
Select to build a U-Boot capable of supporting Intel MID
(Mobile Internet Device) platform systems which do not have
diff --git a/arch/x86/include/asm/cpu.h b/arch/x86/include/asm/cpu.h
index c651f2f594..0ee13b1eb1 100644
--- a/arch/x86/include/asm/cpu.h
+++ b/arch/x86/include/asm/cpu.h
@@ -54,6 +54,7 @@ enum {
X86_NONE,
X86_SYSCON_ME, /* Intel Management Engine */
X86_SYSCON_PINCONF, /* Intel x86 pin configuration */
+ X86_SYSCON_SCU, /* System Controller Unit */
};
struct cpuid_result {
diff --git a/arch/x86/include/asm/scu.h b/arch/x86/include/asm/scu.h
new file mode 100644
index 0000000000..876363cb5c
--- /dev/null
+++ b/arch/x86/include/asm/scu.h
@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2017 Intel Corporation
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+#ifndef _X86_ASM_SCU_IPC_H_
+#define _X86_ASM_SCU_IPC_H_
+
+/* IPC defines the following message types */
+#define IPCMSG_WARM_RESET 0xF0
+#define IPCMSG_COLD_RESET 0xF1
+#define IPCMSG_SOFT_RESET 0xF2
+#define IPCMSG_COLD_BOOT 0xF3
+#define IPCMSG_GET_FW_REVISION 0xF4
+#define IPCMSG_WATCHDOG_TIMER 0xF8 /* Set Kernel Watchdog Threshold */
+
+struct ipc_ifwi_version {
+ u16 minor;
+ u8 major;
+ u8 hardware_id;
+ u32 reserved[3];
+};
+
+/* Issue commands to the SCU with or without data */
+int scu_ipc_simple_command(u32 cmd, u32 sub);
+int scu_ipc_command(u32 cmd, u32 sub, u32 *in, int inlen, u32 *out, int outlen);
+
+#endif /* _X86_ASM_SCU_IPC_H_ */
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index 1c2c085179..320e45e4a0 100644
--- a/arch/x86/lib/Makefile
+++ b/arch/x86/lib/Makefile
@@ -32,6 +32,7 @@ obj-y += pirq_routing.o
obj-y += relocate.o
obj-y += physmem.o
obj-$(CONFIG_X86_RAMTEST) += ramtest.o
+obj-$(CONFIG_INTEL_MID) += scu.o
obj-y += sections.o
obj-y += sfi.o
obj-y += string.o
diff --git a/arch/x86/lib/scu.c b/arch/x86/lib/scu.c
new file mode 100644
index 0000000000..bb23d0b829
--- /dev/null
+++ b/arch/x86/lib/scu.c
@@ -0,0 +1,168 @@
+/*
+ * Copyright (c) 2017 Intel Corporation
+ *
+ * Intel Mobile Internet Devices (MID) based on Intel Atom SoCs have few
+ * microcontrollers inside to do some auxiliary tasks. One of such
+ * microcontroller is System Controller Unit (SCU) which, in particular,
+ * is servicing watchdog and controlling system reset function.
+ *
+ * This driver enables IPC channel to SCU.
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+#include <common.h>
+#include <dm.h>
+#include <regmap.h>
+#include <syscon.h>
+#include <asm/cpu.h>
+#include <asm/scu.h>
+#include <linux/errno.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+
+/* SCU register map */
+struct ipc_regs {
+ u32 cmd;
+ u32 status;
+ u32 sptr;
+ u32 dptr;
+ u32 reserved[28];
+ u32 wbuf[4];
+ u32 rbuf[4];
+};
+
+struct scu {
+ struct ipc_regs *regs;
+};
+
+/**
+ * scu_ipc_send_command() - send command to SCU
+ * @regs: register map of SCU
+ * @cmd: command
+ *
+ * Command Register (Write Only):
+ * A write to this register results in an interrupt to the SCU core processor
+ * Format:
+ * |rfu2(8) | size(8) | command id(4) | rfu1(3) | ioc(1) | command(8)|
+ */
+static void scu_ipc_send_command(struct ipc_regs *regs, u32 cmd)
+{
+ writel(cmd, ®s->cmd);
+}
+
+/**
+ * scu_ipc_check_status() - check status of last command
+ * @regs: register map of SCU
+ *
+ * Status Register (Read Only):
+ * Driver will read this register to get the ready/busy status of the IPC
+ * block and error status of the IPC command that was just processed by SCU
+ * Format:
+ * |rfu3(8)|error code(8)|initiator id(8)|cmd id(4)|rfu1(2)|error(1)|busy(1)|
+ */
+static int scu_ipc_check_status(struct ipc_regs *regs)
+{
+ int loop_count = 100000;
+ int status;
+
+ do {
+ status = readl(®s->status);
+ if (!(status & BIT(0)))
+ break;
+
+ udelay(1);
+ } while (--loop_count);
+ if (!loop_count)
+ return -ETIMEDOUT;
+
+ if (status & BIT(1)) {
+ printf("%s() status=0x%08x\n", __func__, status);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static int scu_ipc_cmd(struct ipc_regs *regs, u32 cmd, u32 sub,
+ u32 *in, int inlen, u32 *out, int outlen)
+{
+ int i, err;
+
+ for (i = 0; i < inlen; i++)
+ writel(*in++, ®s->wbuf[i]);
+
+ scu_ipc_send_command(regs, (inlen << 16) | (sub << 12) | cmd);
+ err = scu_ipc_check_status(regs);
+
+ if (!err) {
+ for (i = 0; i < outlen; i++)
+ *out++ = readl(®s->rbuf[i]);
+ }
+
+ return err;
+}
+
+/**
+ * scu_ipc_simple_command() - send a simple command
+ * @cmd: command
+ * @sub: sub type
+ *
+ * Issue a simple command to the SCU. Do not use this interface if
+ * you must then access data as any data values may be overwritten
+ * by another SCU access by the time this function returns.
+ *
+ * This function may sleep. Locking for SCU accesses is handled for
+ * the caller.
+ */
+int scu_ipc_simple_command(u32 cmd, u32 sub)
+{
+ struct scu *scu;
+ struct udevice *dev;
+ int ret;
+
+ ret = syscon_get_by_driver_data(X86_SYSCON_SCU, &dev);
+ if (ret)
+ return ret;
+
+ scu = dev_get_priv(dev);
+
+ scu_ipc_send_command(scu->regs, sub << 12 | cmd);
+ return scu_ipc_check_status(scu->regs);
+}
+
+int scu_ipc_command(u32 cmd, u32 sub, u32 *in, int inlen, u32 *out, int outlen)
+{
+ struct scu *scu;
+ struct udevice *dev;
+ int ret;
+
+ ret = syscon_get_by_driver_data(X86_SYSCON_SCU, &dev);
+ if (ret)
+ return ret;
+
+ scu = dev_get_priv(dev);
+
+ return scu_ipc_cmd(scu->regs, cmd, sub, in, inlen, out, outlen);
+}
+
+static int scu_ipc_probe(struct udevice *dev)
+{
+ struct scu *scu = dev_get_priv(dev);
+
+ scu->regs = syscon_get_first_range(X86_SYSCON_SCU);
+
+ return 0;
+}
+
+static const struct udevice_id scu_ipc_match[] = {
+ { .compatible = "intel,scu-ipc", .data = X86_SYSCON_SCU },
+ { /* sentinel */ }
+};
+
+U_BOOT_DRIVER(scu_ipc) = {
+ .name = "scu_ipc",
+ .id = UCLASS_SYSCON,
+ .of_match = scu_ipc_match,
+ .probe = scu_ipc_probe,
+ .priv_auto_alloc_size = sizeof(struct scu),
+};
--
2.11.0
More information about the U-Boot
mailing list