x86: Add SCU IPC driver for Intel MID platforms

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@intel.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Simon Glass <sjg@chromium.org>

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 6ce127a23c18b624f05c3893165ad80827d1afec..9ead3ebccf89d1c8737058000528e7e99c78e0c0 100644 (file)
--- 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 c651f2f594535ab47c315d9b9fa4176cfe844748..0ee13b1eb16ff52d37c15986810471c00981c2df 100644 (file)
--- 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 (file)
index 0000000..4d40e49
--- /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 1c2c0851790e296cb3e80a1eaf5d3c1fd74bee5f..320e45e4a061ad1fda23977ab601e16fc962db40 100644 (file)
--- 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 (file)
index 0000000..bb23d0b
--- /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, &regs->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(&regs->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++, &regs->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(&regs->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),
+};