ipmi: add a KCS IPMI BMC driver

Provides a device driver for the KCS (Keyboard Controller Style)
IPMI interface which meets the requirement of the BMC (Baseboard
Management Controllers) side for handling the IPMI request from
host system software.
Signed-off-by: Haiyue Wang <haiyue.wang@linux.intel.com>
[Removed the selectability of IPMI_KCS_BMC, as it doesn't do much
 good to have it by itself.]
Signed-off-by: Corey Minyard <cminyard@mvista.com>

drivers/char/ipmi/Kconfig

@@ -96,6 +96,9 @@ config IPMI_POWEROFF
 
 endif # IPMI_HANDLER
 
+config IPMI_KCS_BMC
+	tristate
+
 config ASPEED_BT_IPMI_BMC
 	depends on ARCH_ASPEED || COMPILE_TEST
        depends on REGMAP && REGMAP_MMIO && MFD_SYSCON

drivers/char/ipmi/Makefile

@@ -21,4 +21,5 @@ obj-$(CONFIG_IPMI_SSIF) += ipmi_ssif.o
 obj-$(CONFIG_IPMI_POWERNV) += ipmi_powernv.o
 obj-$(CONFIG_IPMI_WATCHDOG) += ipmi_watchdog.o
 obj-$(CONFIG_IPMI_POWEROFF) += ipmi_poweroff.o
+obj-$(CONFIG_IPMI_KCS_BMC) += kcs_bmc.o
 obj-$(CONFIG_ASPEED_BT_IPMI_BMC) += bt-bmc.o

drivers/char/ipmi/kcs_bmc.h

+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2015-2018, Intel Corporation.
+
+#ifndef __KCS_BMC_H__
+#define __KCS_BMC_H__
+
+#include <linux/miscdevice.h>
+
+/* Different phases of the KCS BMC module :
+ *  KCS_PHASE_IDLE :
+ *            BMC should not be expecting nor sending any data.
+ *  KCS_PHASE_WRITE_START :
+ *            BMC is receiving a WRITE_START command from system software.
+ *  KCS_PHASE_WRITE_DATA :
+ *            BMC is receiving a data byte from system software.
+ *  KCS_PHASE_WRITE_END_CMD :
+ *            BMC is waiting a last data byte from system software.
+ *  KCS_PHASE_WRITE_DONE :
+ *            BMC has received the whole request from system software.
+ *  KCS_PHASE_WAIT_READ :
+ *            BMC is waiting the response from the upper IPMI service.
+ *  KCS_PHASE_READ :
+ *            BMC is transferring the response to system software.
+ *  KCS_PHASE_ABORT_ERROR1 :
+ *            BMC is waiting error status request from system software.
+ *  KCS_PHASE_ABORT_ERROR2 :
+ *            BMC is waiting for idle status afer error from system software.
+ *  KCS_PHASE_ERROR :
+ *            BMC has detected a protocol violation at the interface level.
+ */
+enum kcs_phases {
+	KCS_PHASE_IDLE,
+
+	KCS_PHASE_WRITE_START,
+	KCS_PHASE_WRITE_DATA,
+	KCS_PHASE_WRITE_END_CMD,
+	KCS_PHASE_WRITE_DONE,
+
+	KCS_PHASE_WAIT_READ,
+	KCS_PHASE_READ,
+
+	KCS_PHASE_ABORT_ERROR1,
+	KCS_PHASE_ABORT_ERROR2,
+	KCS_PHASE_ERROR
+};
+
+/* IPMI 2.0 - Table 9-4, KCS Interface Status Codes */
+enum kcs_errors {
+	KCS_NO_ERROR                = 0x00,
+	KCS_ABORTED_BY_COMMAND      = 0x01,
+	KCS_ILLEGAL_CONTROL_CODE    = 0x02,
+	KCS_LENGTH_ERROR            = 0x06,
+	KCS_UNSPECIFIED_ERROR       = 0xFF
+};
+
+/* IPMI 2.0 - 9.5, KCS Interface Registers
+ * @idr : Input Data Register
+ * @odr : Output Data Register
+ * @str : Status Register
+ */
+struct kcs_ioreg {
+	u32 idr;
+	u32 odr;
+	u32 str;
+};
+
+struct kcs_bmc {
+	spinlock_t lock;
+
+	u32 channel;
+	int running;
+
+	/* Setup by BMC KCS controller driver */
+	struct kcs_ioreg ioreg;
+	u8 (*io_inputb)(struct kcs_bmc *kcs_bmc, u32 reg);
+	void (*io_outputb)(struct kcs_bmc *kcs_bmc, u32 reg, u8 b);
+
+	enum kcs_phases phase;
+	enum kcs_errors error;
+
+	wait_queue_head_t queue;
+	bool data_in_avail;
+	int  data_in_idx;
+	u8  *data_in;
+
+	int  data_out_idx;
+	int  data_out_len;
+	u8  *data_out;
+
+	struct mutex mutex;
+	u8 *kbuffer;
+
+	struct miscdevice miscdev;
+
+	unsigned long priv[];
+};
+
+static inline void *kcs_bmc_priv(struct kcs_bmc *kcs_bmc)
+{
+	return kcs_bmc->priv;
+}
+
+int kcs_bmc_handle_event(struct kcs_bmc *kcs_bmc);
+struct kcs_bmc *kcs_bmc_alloc(struct device *dev, int sizeof_priv,
+					u32 channel);
+#endif

include/uapi/linux/ipmi_bmc.h

+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2015-2018, Intel Corporation.
+
+#ifndef _UAPI_LINUX_IPMI_BMC_H
+#define _UAPI_LINUX_IPMI_BMC_H
+
+#include <linux/ioctl.h>
+
+#define __IPMI_BMC_IOCTL_MAGIC        0xB1
+#define IPMI_BMC_IOCTL_SET_SMS_ATN    _IO(__IPMI_BMC_IOCTL_MAGIC, 0x00)
+#define IPMI_BMC_IOCTL_CLEAR_SMS_ATN  _IO(__IPMI_BMC_IOCTL_MAGIC, 0x01)
+#define IPMI_BMC_IOCTL_FORCE_ABORT    _IO(__IPMI_BMC_IOCTL_MAGIC, 0x02)
+
+#endif /* _UAPI_LINUX_KCS_BMC_H */