7 files changed, 385 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/i2c/i2c-opal.txt b/Documentation/devicetree/bindings/i2c/i2c-opal.txt
new file mode 100644
index 000000000000..12bc61465ee5
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/i2c-opal.txt
@@ -0,0 +1,37 @@
+Device-tree bindings for I2C OPAL driver
+----------------------------------------
+
+Most of the device node and properties layout is specific to the firmware and
+used by the firmware itself for configuring the port. From the linux
+perspective, the properties of use are "ibm,port-name" and "ibm,opal-id".
+
+Required properties:
+
+- reg: Port-id within a given master
+- compatible: must be "ibm,opal-i2c"
+- ibm,opal-id: Refers to a specific bus and used to identify it when calling
+               the relevant OPAL functions.
+- bus-frequency: Operating frequency of the i2c bus (in HZ). Informational for
+                 linux, used by the FW though.
+
+Optional properties:
+- ibm,port-name: Firmware provides this name that uniquely identifies the i2c
+                 port.
+
+The node contains a number of other properties that are used by the FW itself
+and depend on the specific hardware implementation. The example below depicts
+a P8 on-chip bus.
+
+Example:
+
+i2c-bus@0 {
+        reg = <0x0>;
+        bus-frequency = <0x61a80>;
+        compatible = "ibm,power8-i2c-port", "ibm,opal-i2c";
+        ibm,opal-id = <0x1>;
+        ibm,port-name = "p8_00000000_e1p0";
+        #address-cells = <0x1>;
+        phandle = <0x10000006>;
+        #size-cells = <0x0>;
+        linux,phandle = <0x10000006>;
+};
diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h
index 5cd8d2fddba9..4095749c973f 100644
--- a/arch/powerpc/include/asm/opal.h
+++ b/arch/powerpc/include/asm/opal.h
@@ -56,6 +56,14 @@ struct opal_sg_list {
 #define OPAL_HARDWARE_FROZEN    -13
 #define OPAL_WRONG_STATE        -14
 #define OPAL_ASYNC_COMPLETION   -15
+#define OPAL_I2C_TIMEOUT        -17
+#define OPAL_I2C_INVALID_CMD    -18
+#define OPAL_I2C_LBUS_PARITY    -19
+#define OPAL_I2C_BKEND_OVERRUN  -20
+#define OPAL_I2C_BKEND_ACCESS   -21
+#define OPAL_I2C_ARBT_LOST      -22
+#define OPAL_I2C_NACK_RCVD      -23
+#define OPAL_I2C_STOP_ERR       -24
 
 /* API Tokens (in r0) */
 #define OPAL_INVALID_CALL                       -1
@@ -158,6 +166,7 @@ struct opal_sg_list {
 #define OPAL_READ_TPO                           104
 #define OPAL_IPMI_SEND                          107
 #define OPAL_IPMI_RECV                          108
+#define OPAL_I2C_REQUEST                        109
 
 #ifndef __ASSEMBLY__
 
@@ -712,6 +721,24 @@ typedef struct oppanel_line {
         uint64_t        line_len;
 } oppanel_line_t;
 
+/* OPAL I2C request */
+struct opal_i2c_request {
+        uint8_t type;
+#define OPAL_I2C_RAW_READ       0
+#define OPAL_I2C_RAW_WRITE      1
+#define OPAL_I2C_SM_READ        2
+#define OPAL_I2C_SM_WRITE       3
+        uint8_t flags;
+#define OPAL_I2C_ADDR_10        0x01    /* Not supported yet */
+        uint8_t subaddr_sz;             /* Max 4 */
+        uint8_t reserved;
+        __be16 addr;                    /* 7 or 10 bit address */
+        __be16 reserved2;
+        __be32 subaddr;         /* Sub-address if any */
+        __be32 size;                    /* Data size */
+        __be64 buffer_ra;               /* Buffer real address */
+};
+
 /* /sys/firmware/opal */
 extern struct kobject *opal_kobj;
 
@@ -881,6 +908,8 @@ int64_t opal_ipmi_send(uint64_t interface, struct opal_ipmi_msg *msg,
                 uint64_t msg_len);
 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);
 
 /* Internal functions */
 extern int early_init_dt_scan_opal(unsigned long node, const char *uname,
diff --git a/arch/powerpc/platforms/powernv/opal-wrappers.S b/arch/powerpc/platforms/powernv/opal-wrappers.S
index 0a299be588af..2111e08d406b 100644
--- a/arch/powerpc/platforms/powernv/opal-wrappers.S
+++ b/arch/powerpc/platforms/powernv/opal-wrappers.S
@@ -254,3 +254,4 @@ OPAL_CALL(opal_tpo_write,			OPAL_WRITE_TPO);
 OPAL_CALL(opal_tpo_read,                        OPAL_READ_TPO);
 OPAL_CALL(opal_ipmi_send,                       OPAL_IPMI_SEND);
 OPAL_CALL(opal_ipmi_recv,                       OPAL_IPMI_RECV);
+OPAL_CALL(opal_i2c_request,                     OPAL_I2C_REQUEST);
diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
index cb0b6de79cd4..aa316d820736 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -653,6 +653,14 @@ static void opal_ipmi_init(struct device_node *opal_node)
                         of_platform_device_create(np, NULL, NULL);
 }
 
+static void opal_i2c_create_devs(void)
+{
+        struct device_node *np;
+
+        for_each_compatible_node(np, NULL, "ibm,opal-i2c")
+                of_platform_device_create(np, NULL, NULL);
+}
+
 static int __init opal_init(void)
 {
         struct device_node *np, *consoles;
@@ -679,6 +687,9 @@ static int __init opal_init(void)
                 of_node_put(consoles);
         }
 
+        /* Create i2c platform devices */
+        opal_i2c_create_devs();
+
         /* Find all OPAL interrupts and request them */
         irqs = of_get_property(opal_node, "opal-interrupts", &irqlen);
         pr_debug("opal: Found %d interrupts reserved for OPAL\n",
@@ -824,3 +835,4 @@ EXPORT_SYMBOL_GPL(opal_rtc_read);
 EXPORT_SYMBOL_GPL(opal_rtc_write);
 EXPORT_SYMBOL_GPL(opal_tpo_read);
 EXPORT_SYMBOL_GPL(opal_tpo_write);
+EXPORT_SYMBOL_GPL(opal_i2c_request);
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 917c3585f45b..71ad6e11efb7 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -1044,4 +1044,15 @@ config SCx200_ACB
           This support is also available as a module.  If so, the module
           will be called scx200_acb.
 
+config I2C_OPAL
+        tristate "IBM OPAL I2C driver"
+        depends on PPC_POWERNV
+        default y
+        help
+          This exposes the PowerNV platform i2c busses to the linux i2c layer,
+          the driver is based on the OPAL interfaces.
+
+          This driver can also be built as a module. If so, the module will be
+          called as i2c-opal.
+
 endmenu
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 78d56c54ba2b..e23ec815e21f 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -99,6 +99,7 @@ obj-$(CONFIG_I2C_ACORN)		+= i2c-acorn.o
 obj-$(CONFIG_I2C_BCM_KONA)      += i2c-bcm-kona.o
 obj-$(CONFIG_I2C_CROS_EC_TUNNEL)        += i2c-cros-ec-tunnel.o
 obj-$(CONFIG_I2C_ELEKTOR)       += i2c-elektor.o
+obj-$(CONFIG_I2C_OPAL)          += i2c-opal.o
 obj-$(CONFIG_I2C_PCA_ISA)       += i2c-pca-isa.o
 obj-$(CONFIG_I2C_SIBYTE)        += i2c-sibyte.o
 obj-$(CONFIG_SCx200_ACB)        += scx200_acb.o
diff --git a/drivers/i2c/busses/i2c-opal.c b/drivers/i2c/busses/i2c-opal.c
new file mode 100644
index 000000000000..16f90b1a7508
--- /dev/null
+++ b/drivers/i2c/busses/i2c-opal.c
@@ -0,0 +1,294 @@
+/*
+ * IBM OPAL I2C driver
+ * Copyright (C) 2014 IBM
+ *
+ * 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 of the License, 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.
+ */
+
+#include <linux/device.h>
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#include <asm/firmware.h>
+#include <asm/opal.h>
+
+static int i2c_opal_translate_error(int rc)
+{
+        switch (rc) {
+        case OPAL_NO_MEM:
+                return -ENOMEM;
+        case OPAL_PARAMETER:
+                return -EINVAL;
+        case OPAL_I2C_ARBT_LOST:
+                return -EAGAIN;
+        case OPAL_I2C_TIMEOUT:
+                return -ETIMEDOUT;
+        case OPAL_I2C_NACK_RCVD:
+                return -ENXIO;
+        case OPAL_I2C_STOP_ERR:
+                return -EBUSY;
+        default:
+                return -EIO;
+        }
+}
+
+static int i2c_opal_send_request(u32 bus_id, struct opal_i2c_request *req)
+{
+        struct opal_msg msg;
+        int token, rc;
+
+        token = opal_async_get_token_interruptible();
+        if (token < 0) {
+                if (token != -ERESTARTSYS)
+                        pr_err("Failed to get the async token\n");
+
+                return token;
+        }
+
+        rc = opal_i2c_request(token, bus_id, req);
+        if (rc != OPAL_ASYNC_COMPLETION) {
+                rc = i2c_opal_translate_error(rc);
+                goto exit;
+        }
+
+        rc = opal_async_wait_response(token, &msg);
+        if (rc)
+                goto exit;
+
+        rc = be64_to_cpu(msg.params[1]);
+        if (rc != OPAL_SUCCESS) {
+                rc = i2c_opal_translate_error(rc);
+                goto exit;
+        }
+
+exit:
+        opal_async_release_token(token);
+        return rc;
+}
+
+static int i2c_opal_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
+                                int num)
+{
+        unsigned long opal_id = (unsigned long)adap->algo_data;
+        struct opal_i2c_request req;
+        int rc, i;
+
+        /* We only support fairly simple combinations here of one
+         * or two messages
+         */
+        memset(&req, 0, sizeof(req));
+        switch(num) {
+        case 0:
+                return 0;
+        case 1:
+                req.type = (msgs[0].flags & I2C_M_RD) ?
+                        OPAL_I2C_RAW_READ : OPAL_I2C_RAW_WRITE;
+                req.addr = cpu_to_be16(msgs[0].addr);
+                req.size = cpu_to_be32(msgs[0].len);
+                req.buffer_ra = cpu_to_be64(__pa(msgs[0].buf));
+                break;
+        case 2:
+                /* For two messages, we basically support only simple
+                 * smbus transactions of a write plus a read. We might
+                 * want to allow also two writes but we'd have to bounce
+                 * the data into a single buffer.
+                 */
+                if ((msgs[0].flags & I2C_M_RD) || !(msgs[1].flags & I2C_M_RD))
+                        return -EOPNOTSUPP;
+                if (msgs[0].len > 4)
+                        return -EOPNOTSUPP;
+                if (msgs[0].addr != msgs[1].addr)
+                        return -EOPNOTSUPP;
+                req.type = OPAL_I2C_SM_READ;
+                req.addr = cpu_to_be16(msgs[0].addr);
+                req.subaddr_sz = msgs[0].len;
+                for (i = 0; i < msgs[0].len; i++)
+                        req.subaddr = (req.subaddr << 8) | msgs[0].buf[i];
+                req.subaddr = cpu_to_be32(req.subaddr);
+                req.size = cpu_to_be32(msgs[1].len);
+                req.buffer_ra = cpu_to_be64(__pa(msgs[1].buf));
+                break;
+        default:
+                return -EOPNOTSUPP;
+        }
+
+        rc = i2c_opal_send_request(opal_id, &req);
+        if (rc)
+                return rc;
+
+        return num;
+}
+
+static int i2c_opal_smbus_xfer(struct i2c_adapter *adap, u16 addr,
+                               unsigned short flags, char read_write,
+                               u8 command, int size, union i2c_smbus_data *data)
+{
+        unsigned long opal_id = (unsigned long)adap->algo_data;
+        struct opal_i2c_request req;
+        u8 local[2];
+        int rc;
+
+        memset(&req, 0, sizeof(req));
+
+        req.addr = cpu_to_be16(addr);
+        switch (size) {
+        case I2C_SMBUS_BYTE:
+                req.buffer_ra = cpu_to_be64(__pa(&data->byte));
+                req.size = cpu_to_be32(1);
+                /* Fall through */
+        case I2C_SMBUS_QUICK:
+                req.type = (read_write == I2C_SMBUS_READ) ?
+                        OPAL_I2C_RAW_READ : OPAL_I2C_RAW_WRITE;
+                break;
+        case I2C_SMBUS_BYTE_DATA:
+                req.buffer_ra = cpu_to_be64(__pa(&data->byte));
+                req.size = cpu_to_be32(1);
+                req.subaddr = cpu_to_be32(command);
+                req.subaddr_sz = 1;
+                req.type = (read_write == I2C_SMBUS_READ) ?
+                        OPAL_I2C_SM_READ : OPAL_I2C_SM_WRITE;
+                break;
+        case I2C_SMBUS_WORD_DATA:
+                if (!read_write) {
+                        local[0] = data->word & 0xff;
+                        local[1] = (data->word >> 8) & 0xff;
+                }
+                req.buffer_ra = cpu_to_be64(__pa(local));
+                req.size = cpu_to_be32(2);
+                req.subaddr = cpu_to_be32(command);
+                req.subaddr_sz = 1;
+                req.type = (read_write == I2C_SMBUS_READ) ?
+                        OPAL_I2C_SM_READ : OPAL_I2C_SM_WRITE;
+                break;
+        case I2C_SMBUS_I2C_BLOCK_DATA:
+                req.buffer_ra = cpu_to_be64(__pa(&data->block[1]));
+                req.size = cpu_to_be32(data->block[0]);
+                req.subaddr = cpu_to_be32(command);
+                req.subaddr_sz = 1;
+                req.type = (read_write == I2C_SMBUS_READ) ?
+                        OPAL_I2C_SM_READ : OPAL_I2C_SM_WRITE;
+                break;
+        default:
+                return -EINVAL;
+        }
+
+        rc = i2c_opal_send_request(opal_id, &req);
+        if (!rc && read_write && size == I2C_SMBUS_WORD_DATA) {
+                data->word = ((u16)local[1]) << 8;
+                data->word |= local[0];
+        }
+
+        return rc;
+}
+
+static u32 i2c_opal_func(struct i2c_adapter *adapter)
+{
+        return I2C_FUNC_I2C | I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
+               I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
+               I2C_FUNC_SMBUS_I2C_BLOCK;
+}
+
+static const struct i2c_algorithm i2c_opal_algo = {
+        .master_xfer    = i2c_opal_master_xfer,
+        .smbus_xfer     = i2c_opal_smbus_xfer,
+        .functionality  = i2c_opal_func,
+};
+
+static int i2c_opal_probe(struct platform_device *pdev)
+{
+        struct i2c_adapter      *adapter;
+        const char              *pname;
+        u32                     opal_id;
+        int                     rc;
+
+        if (!pdev->dev.of_node)
+                return -ENODEV;
+
+        rc = of_property_read_u32(pdev->dev.of_node, "ibm,opal-id", &opal_id);
+        if (rc) {
+                dev_err(&pdev->dev, "Missing ibm,opal-id property !\n");
+                return -EIO;
+        }
+
+        adapter = devm_kzalloc(&pdev->dev, sizeof(*adapter), GFP_KERNEL);
+        if (!adapter)
+                return -ENOMEM;
+
+        adapter->algo = &i2c_opal_algo;
+        adapter->algo_data = (void *)(unsigned long)opal_id;
+        adapter->dev.parent = &pdev->dev;
+        adapter->dev.of_node = of_node_get(pdev->dev.of_node);
+        pname = of_get_property(pdev->dev.of_node, "ibm,port-name", NULL);
+        if (pname)
+                strlcpy(adapter->name, pname, sizeof(adapter->name));
+        else
+                strlcpy(adapter->name, "opal", sizeof(adapter->name));
+
+        platform_set_drvdata(pdev, adapter);
+        rc = i2c_add_adapter(adapter);
+        if (rc)
+                dev_err(&pdev->dev, "Failed to register the i2c adapter\n");
+
+        return rc;
+}
+
+static int i2c_opal_remove(struct platform_device *pdev)
+{
+        struct i2c_adapter *adapter = platform_get_drvdata(pdev);
+
+        i2c_del_adapter(adapter);
+
+        return 0;
+}
+
+static const struct of_device_id i2c_opal_of_match[] = {
+        {
+                .compatible = "ibm,opal-i2c",
+        },
+        { }
+};
+MODULE_DEVICE_TABLE(of, i2c_opal_of_match);
+
+static struct platform_driver i2c_opal_driver = {
+        .probe  = i2c_opal_probe,
+        .remove = i2c_opal_remove,
+        .driver = {
+                .name           = "i2c-opal",
+                .of_match_table = i2c_opal_of_match,
+        },
+};
+
+static int __init i2c_opal_init(void)
+{
+        if (!firmware_has_feature(FW_FEATURE_OPAL))
+                return -ENODEV;
+
+        return platform_driver_register(&i2c_opal_driver);
+}
+module_init(i2c_opal_init);
+
+static void __exit i2c_opal_exit(void)
+{
+        return platform_driver_unregister(&i2c_opal_driver);
+}
+module_exit(i2c_opal_exit);
+
+MODULE_AUTHOR("Neelesh Gupta <neelegup@linux.vnet.ibm.com>");
+MODULE_DESCRIPTION("IBM OPAL I2C driver");
+MODULE_LICENSE("GPL");