powerpc/powernv: Add opal-prd channel

This change adds a char device to access the "PRD" (processor runtime
diagnostics) channel to OPAL firmware.

Includes contributions from Vaidyanathan Srinivasan, Neelesh Gupta &
Vishal Kulkarni.
Signed-off-by: Neelesh Gupta <neelegup@linux.vnet.ibm.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Acked-by: Stewart Smith <stewart@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/include/asm/opal-api.h

@@ -153,7 +153,8 @@
 #define OPAL_FLASH_READ				110
 #define OPAL_FLASH_WRITE			111
 #define OPAL_FLASH_ERASE			112
-#define OPAL_LAST				112
+#define OPAL_PRD_MSG				113
+#define OPAL_LAST				113
 
 /* Device tree flags */
 
@@ -359,6 +360,7 @@ enum opal_msg_type {
 	OPAL_MSG_SHUTDOWN,		/* params[0] = 1 reboot, 0 shutdown */
 	OPAL_MSG_HMI_EVT,
 	OPAL_MSG_DPO,
+	OPAL_MSG_PRD,
 	OPAL_MSG_TYPE_MAX,
 };
 
@@ -681,6 +683,23 @@ typedef struct oppanel_line {
 	__be64 line_len;
 } oppanel_line_t;
 
+enum opal_prd_msg_type {
+	OPAL_PRD_MSG_TYPE_INIT = 0,	/* HBRT --> OPAL */
+	OPAL_PRD_MSG_TYPE_FINI,		/* HBRT/kernel --> OPAL */
+	OPAL_PRD_MSG_TYPE_ATTN,		/* HBRT <-- OPAL */
+	OPAL_PRD_MSG_TYPE_ATTN_ACK,	/* HBRT --> OPAL */
+	OPAL_PRD_MSG_TYPE_OCC_ERROR,	/* HBRT <-- OPAL */
+	OPAL_PRD_MSG_TYPE_OCC_RESET,	/* HBRT <-- OPAL */
+};
+
+struct opal_prd_msg_header {
+	uint8_t		type;
+	uint8_t		pad[1];
+	__be16		size;
+};
+
+struct opal_prd_msg;
+
 /*
  * SG entries
  *

arch/powerpc/include/asm/opal.h

@@ -194,6 +194,7 @@ int64_t opal_ipmi_recv(uint64_t interface, struct opal_ipmi_msg *msg,
 		uint64_t *msg_len);
 int64_t opal_i2c_request(uint64_t async_token, uint32_t bus_id,
 			 struct opal_i2c_request *oreq);
+int64_t opal_prd_msg(struct opal_prd_msg *msg);
 
 int64_t opal_flash_read(uint64_t id, uint64_t offset, uint64_t buf,
 		uint64_t size, uint64_t token);

arch/powerpc/include/uapi/asm/opal-prd.h

+/*
+ * OPAL Runtime Diagnostics interface driver
+ * Supported on POWERNV platform
+ *
+ * (C) Copyright IBM 2015
+ *
+ * Author: Vaidyanathan Srinivasan <svaidy at linux.vnet.ibm.com>
+ * Author: Jeremy Kerr <jk@ozlabs.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef _UAPI_ASM_POWERPC_OPAL_PRD_H_
+#define _UAPI_ASM_POWERPC_OPAL_PRD_H_
+
+#include <linux/types.h>
+
+/**
+ * The version of the kernel interface of the PRD system. This describes the
+ * interface available for the /dev/opal-prd device. The actual PRD message
+ * layout and content is private to the firmware <--> userspace interface, so
+ * is not covered by this versioning.
+ *
+ * Future interface versions are backwards-compatible; if a later kernel
+ * version is encountered, functionality provided in earlier versions
+ * will work.
+ */
+#define OPAL_PRD_KERNEL_VERSION		1
+
+#define OPAL_PRD_GET_INFO		_IOR('o', 0x01, struct opal_prd_info)
+#define OPAL_PRD_SCOM_READ		_IOR('o', 0x02, struct opal_prd_scom)
+#define OPAL_PRD_SCOM_WRITE		_IOW('o', 0x03, struct opal_prd_scom)
+
+#ifndef __ASSEMBLY__
+
+struct opal_prd_info {
+	__u64	version;
+	__u64	reserved[3];
+};
+
+struct opal_prd_scom {
+	__u64	chip;
+	__u64	addr;
+	__u64	data;
+	__s64	rc;
+};
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* _UAPI_ASM_POWERPC_OPAL_PRD_H */

arch/powerpc/platforms/powernv/Kconfig

@@ -19,3 +19,10 @@ config PPC_POWERNV
 	select CPU_FREQ_GOV_CONSERVATIVE
 	select PPC_DOORBELL
 	default y
+
+config OPAL_PRD
+	tristate 'OPAL PRD driver'
+	depends on PPC_POWERNV
+	help
+	  This enables the opal-prd driver, a facility to run processor
+	  recovery diagnostics on OpenPower machines

arch/powerpc/platforms/powernv/Makefile

@@ -9,3 +9,4 @@ obj-$(CONFIG_EEH)	+= eeh-powernv.o
 obj-$(CONFIG_PPC_SCOM)	+= opal-xscom.o
 obj-$(CONFIG_MEMORY_FAILURE)	+= opal-memory-errors.o
 obj-$(CONFIG_TRACEPOINTS)	+= opal-tracepoints.o
+obj-$(CONFIG_OPAL_PRD)	+= opal-prd.o

arch/powerpc/platforms/powernv/opal-wrappers.S

@@ -296,3 +296,4 @@ OPAL_CALL(opal_i2c_request,			OPAL_I2C_REQUEST);
 OPAL_CALL(opal_flash_read,			OPAL_FLASH_READ);
 OPAL_CALL(opal_flash_write,			OPAL_FLASH_WRITE);
 OPAL_CALL(opal_flash_erase,			OPAL_FLASH_ERASE);
+OPAL_CALL(opal_prd_msg,				OPAL_PRD_MSG);

arch/powerpc/platforms/powernv/opal.c

@@ -711,9 +711,10 @@ static int __init opal_init(void)
 		opal_msglog_init();
 	}
 
-	/* Initialize platform devices: IPMI backend & flash interface */
+	/* Initialize platform devices: IPMI backend, PRD & flash interface */
 	opal_pdev_init(opal_node, "ibm,opal-ipmi");
 	opal_pdev_init(opal_node, "ibm,opal-flash");
+	opal_pdev_init(opal_node, "ibm,opal-prd");
 
 	return 0;
 }
@@ -752,6 +753,7 @@ EXPORT_SYMBOL_GPL(opal_ipmi_recv);
 EXPORT_SYMBOL_GPL(opal_flash_read);
 EXPORT_SYMBOL_GPL(opal_flash_write);
 EXPORT_SYMBOL_GPL(opal_flash_erase);
+EXPORT_SYMBOL_GPL(opal_prd_msg);
 
 /* Convert a region of vmalloc memory to an opal sg list */
 struct opal_sg_list *opal_vmalloc_to_sg_list(void *vmalloc_addr,