This change enables the Linux driver to access i2c devices via
the Tilera hypervisor's virtualized API.
Note that the arch/tile/include/hv/ headers are "upstream" headers
that likely benefit less from LKML review.
Signed-off-by: Chris Metcalf <cmetcalf@xxxxxxxxxx>
---
arch/tile/include/hv/drv_i2cm_intf.h | 68 +++++++
drivers/i2c/busses/Kconfig | 10 +
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-tile.c | 324 ++++++++++++++++++++++++++++++++++
4 files changed, 403 insertions(+), 0 deletions(-)
create mode 100644 arch/tile/include/hv/drv_i2cm_intf.h
create mode 100644 drivers/i2c/busses/i2c-tile.c
diff --git a/arch/tile/include/hv/drv_i2cm_intf.h b/arch/tile/include/hv/drv_i2cm_intf.h
new file mode 100644
index 0000000..6584a72
--- /dev/null
+++ b/arch/tile/include/hv/drv_i2cm_intf.h
@@ -0,0 +1,68 @@
+/*
+ * Copyright 2010 Tilera Corporation. All Rights Reserved.
+ *
+ * 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, version 2.
+ *
+ * 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, GOOD TITLE or
+ * NON INFRINGEMENT. See the GNU General Public License for
+ * more details.
+ */
+
+/**
+ * @file drv_i2cm_intf.h
+ * Interface definitions for the I2CM driver.
+ *
+ * The I2C Master interface driver provides a manner for supervisors to
+ * access the I2C devices on the I2C bus.
+ *
+ * When the supervisor issues an I2C data transaction, it stores the i2c
+ * device slave address and the data offset within the device in the offset
+ * of the HV I2C device handle. The low half-word contains the slave address
+ * while the data offset is stored in byte 2 and 3. For the write access,
+ * the first 1 or 2 bytes of the write data contain the device data address
+ * if the data offset field of the HV device handle offset is 0; otherwise,
+ * the write data are puse data payload. For the read access, it is always
+ * preceded by a dummy write access which should contain an either 1-byte or
+ * 2-byte device data address while the read message holds no addressing
+ * information.
+ */
+
+#ifndef _SYS_HV_INCLUDE_DRV_I2CM_INTF_H
+#define _SYS_HV_INCLUDE_DRV_I2CM_INTF_H
+
+/** Maximum size of an HV I2C transfer. */
+#define HV_I2CM_CHUNK_SIZE 128
+
+/** Length of the i2c device name. */
+#define I2C_DEV_NAME_SIZE 20
+
+/** I2C device descriptor, to be exported to the client OS. */
+typedef struct
+{
+ char name[I2C_DEV_NAME_SIZE]; /**< Device name, e.g. "24c512". */
+ uint32_t addr; /**< I2C device slave address */
+}
+tile_i2c_desc_t;
+
+/** Get the number of i2c devices. Read-only, takes a 4-byte value. */
+#define I2C_GET_NUM_DEVS_OFF 0xF0000000
+
+/** Get i2c device info. Read-only, takes an array of tile_i2c_desc_t's. */
+#define I2C_GET_DEV_INFO_OFF 0xF0000004
+
+/** This structure is used to encode the I2C device slave address
+ * and the chip data offset and is passed to the HV in the offset
+ * of the i2cm HV device file.
+ */
+typedef struct
+{
+ uint32_t addr:8; /**< I2C device slave address */
+ uint32_t data_offset:24; /**< I2C device data offset */
+}
+tile_i2c_addr_desc_t;
+
+#endif /* _SYS_HV_INCLUDE_DRV_I2CM_INTF_H */
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 3a6321c..5d8d8ab 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -607,6 +607,16 @@ config I2C_STU300
This driver can also be built as a module. If so, the module
will be called i2c-stu300.
+config I2C_TILE
+ tristate "Tilera I2C hypervisor interface"
+ depends on TILE
+ help
+ This supports the Tilera hypervisor interface for
+ communicating with I2C devices attached to the chip.
+
+ This driver can also be built as a module. If so, the module
+ will be called i2c-tile.
+
config I2C_VERSATILE
tristate "ARM Versatile/Realview I2C bus support"
depends on ARCH_VERSATILE || ARCH_REALVIEW || ARCH_VEXPRESS
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 84cb16a..0a739eb 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -58,6 +58,7 @@ obj-$(CONFIG_I2C_SH7760) += i2c-sh7760.o
obj-$(CONFIG_I2C_SH_MOBILE) += i2c-sh_mobile.o
obj-$(CONFIG_I2C_SIMTEC) += i2c-simtec.o
obj-$(CONFIG_I2C_STU300) += i2c-stu300.o
+obj-$(CONFIG_I2C_TILE) += i2c-tile.o
obj-$(CONFIG_I2C_VERSATILE) += i2c-versatile.o
obj-$(CONFIG_I2C_OCTEON) += i2c-octeon.o
obj-$(CONFIG_I2C_XILINX) += i2c-xiic.o
diff --git a/drivers/i2c/busses/i2c-tile.c b/drivers/i2c/busses/i2c-tile.c
new file mode 100644
index 0000000..b4e8988
--- /dev/null
+++ b/drivers/i2c/busses/i2c-tile.c
@@ -0,0 +1,324 @@
+/*
+ * Copyright 2010 Tilera Corporation. All Rights Reserved.
+ *
+ * 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, version 2.
+ *
+ * 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, GOOD TITLE or
+ * NON INFRINGEMENT. See the GNU General Public License for
+ * more details.
+ *
+ * Tilera-specific I2C driver.
+ *
+ * This source code is derived from the following driver:
+ *
+ * i2c Support for Atmel's AT91 Two-Wire Interface (TWI)
+ *
+ * Copyright (C) 2004 Rick Bronson
+ * Converted to 2.6 by Andrew Victor <andrew@xxxxxxxxxxxxx>
+ *
+ * Borrowed heavily from original work by:
+ * Copyright (C) 2000 Philip Edelbrock <phil@xxxxxxxxxxxxxxxxxxxx>
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/errno.h>
+#include <linux/platform_device.h>
+#include <linux/uaccess.h>
+#include <hv/hypervisor.h>
+#include <hv/drv_i2cm_intf.h>
+
+#define DRV_NAME "i2c-tile"
+
+static char i2cm_device[16] = "i2cm/0";
+
+/* Handle for hypervisor device. */
+static int i2cm_hv_devhdl;
+
+/*
+ * The I2C platform device.
+ */
+static struct platform_device *i2c_platform_device;
+
+static int xfer_msg(struct i2c_adapter *adap, struct i2c_msg *pmsg)
+{
+ int retval = 0;
+ int data_offset = 0;
+ int addr = pmsg->addr;
+ int length = pmsg->len;
+ char *buf = pmsg->buf;
+
+ /* HV uses 8-bit slave addresses. */
+ addr <<= 1;
+
+ while (length) {
+ int hv_retval;
+ tile_i2c_addr_desc_t hv_offset = {
+ .addr = addr,
+ .data_offset = data_offset,
+ };
+
+ int bytes_this_pass = length;
+ if (bytes_this_pass > HV_I2CM_CHUNK_SIZE)
+ bytes_this_pass = HV_I2CM_CHUNK_SIZE;
+
+ if (pmsg->flags & I2C_M_RD)
+ hv_retval = hv_dev_pread(i2cm_hv_devhdl, 0,
+ (HV_VirtAddr) buf,
+ bytes_this_pass,
+ *(int *) &hv_offset);
+ else
+ hv_retval = hv_dev_pwrite(i2cm_hv_devhdl, 0,
+ (HV_VirtAddr) buf,
+ bytes_this_pass,
+ *(int *) &hv_offset);
+ if (hv_retval < 0) {
+ pr_err(DRV_NAME ": %s failed, error %d\n",
+ (pmsg->flags & I2C_M_RD) ? "hv_dev_pread" :
+ "hv_dev_pwrite", hv_retval);
+ if (hv_retval == HV_ENODEV)
+ retval = -ENODEV;
+ else
+ retval = -EIO;
+ break;
+ }
+
+ buf += hv_retval;
+ data_offset += hv_retval;
+ length -= hv_retval;
+ }
+
+ return retval;
+}
+
+/*
+ * Generic I2C master transfer routine.
+ */
+static int tile_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *pmsg,
+ int num)
+{
+ int ret, i;
+
+ /* We don't support ten bit chip address. */
+ if (pmsg->flags & I2C_M_TEN)
+ return -EINVAL;
+
+ for (i = 0; i < num; i++) {
+ if (pmsg->len && pmsg->buf) {
+
+ ret = xfer_msg(adap, pmsg);
+ if (ret)
+ return ret;
+
+ pmsg++;
+ } else
+ return -EINVAL;
+ }
+
+ return i;
+}
+
+/*
+ * Return list of supported functionality.
+ */
+static u32 tile_i2c_functionality(struct i2c_adapter *adap)
+{
+ return I2C_FUNC_I2C;
+}
+
+static const struct i2c_algorithm tile_i2c_algorithm = {
+ .master_xfer = tile_i2c_xfer,
+ .functionality = tile_i2c_functionality,
+};
+
+/*
+ * This routine is called to register all I2C devices that are connected to
+ * the I2C bus. This should be done at arch_initcall time, before declaring
+ * the I2C adapter. This function does the following:
+ *
+ * 1. Retrieve the I2C device list from the HV which selectively grants the
+ * access permission of individual I2C devices, and build an array of struct
+ * i2c_board_info.
+ * 2. Statically declare these I2C devices by calling
+ * i2c_register_board_info().
+ */
+static int __init tile_i2c_dev_init(void)
+{
+ int ret;
+ int i;
+ int i2c_devs = 0;
+ struct i2c_board_info *tile_i2c_devices;
+ int i2c_desc_size;
+ tile_i2c_desc_t *tile_i2c_desc;
+
+ /* Open the HV i2cm device. */
+ i2cm_hv_devhdl = hv_dev_open((HV_VirtAddr)i2cm_device, 0);
+ if (i2cm_hv_devhdl < 0) {
+ switch (i2cm_hv_devhdl) {
+ case HV_ENODEV:
+ return -ENODEV;
+ default:
+ return (ssize_t)i2cm_hv_devhdl;
+ }
+ }
+
+ ret = hv_dev_pread(i2cm_hv_devhdl, 0, (HV_VirtAddr)&i2c_devs,
+ sizeof(i2c_devs), I2C_GET_NUM_DEVS_OFF);
+ if (ret <= 0) {
+ pr_err(DRV_NAME ": hv_dev_pread(I2C_GET_NUM_DEVS_OFF)"
+ " failed, error %d\n", ret);
+ return -EIO;
+ }
+
+ if (i2c_devs == 0)
+ return 0;
+
+ pr_info(DRV_NAME ": detected %d I2C devices.\n", i2c_devs);
+
+ i2c_desc_size = i2c_devs * sizeof(tile_i2c_desc_t);
+ tile_i2c_desc = kzalloc(i2c_desc_size, GFP_KERNEL);
+ if (!tile_i2c_desc)
+ return -ENOMEM;
+
+ ret = hv_dev_pread(i2cm_hv_devhdl, 0, (HV_VirtAddr)tile_i2c_desc,
+ i2c_desc_size, I2C_GET_DEV_INFO_OFF);
+ if (ret <= 0) {
+ pr_err(DRV_NAME ": hv_dev_pread(I2C_GET_DEV_INFO_OFF)"
+ " failed, error %d\n", ret);
+ return -EIO;
+ }
+
+ i2c_desc_size = i2c_devs * sizeof(struct i2c_board_info);
+ tile_i2c_devices = kzalloc(i2c_desc_size, GFP_KERNEL);
+ if (!tile_i2c_devices)
+ return -ENOMEM;
+
+ for (i = 0; i < i2c_devs; i++) {
+ strncpy(tile_i2c_devices[i].type, tile_i2c_desc[i].name,
+ I2C_NAME_SIZE);
+ /* HV uses 8-bit slave addresses, convert to 7bit for Linux. */
+ tile_i2c_devices[i].addr = tile_i2c_desc[i].addr >> 1;
+ }
+
+ ret = i2c_register_board_info(0, tile_i2c_devices, i2c_devs);
+
+ kfree(tile_i2c_desc);
+ kfree(tile_i2c_devices);
+
+ return ret;
+}
+arch_initcall(tile_i2c_dev_init);
+
+/*
+ * I2C adapter probe routine which registers the I2C adapter with the I2C core.
+ */
+static int __devinit tile_i2c_probe(struct platform_device *dev)
+{
+ struct i2c_adapter *adapter;
+ int ret;
+
+ adapter = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL);
+ if (adapter == NULL) {
+ ret = -ENOMEM;
+ goto malloc_err;
+ }
+
+ adapter->owner = THIS_MODULE;
+
+ /*
+ * If "dev->id" is negative we consider it as zero.
+ * The reason to do so is to avoid sysfs names that only make
+ * sense when there are multiple adapters.
+ */
+ adapter->nr = dev->id != -1 ? dev->id : 0;
+ snprintf(adapter->name, sizeof(adapter->name), "tile_i2c-i2c.%u",
+ adapter->nr);
+
+ adapter->algo = &tile_i2c_algorithm;
+ adapter->class = I2C_CLASS_HWMON;
+ adapter->dev.parent = &dev->dev;
+
+ ret = i2c_add_numbered_adapter(adapter);
+ if (ret < 0) {
+ pr_info(DRV_NAME ": %s registration failed\n",
+ adapter->name);
+ goto add_adapter_err;
+ }
+
+ platform_set_drvdata(dev, adapter);
+
+ return 0;
+
+add_adapter_err:
+ kfree(adapter);
+malloc_err:
+ return ret;
+}
+
+/*
+ * I2C adapter cleanup routine.
+ */
+static int __devexit tile_i2c_remove(struct platform_device *dev)
+{
+ struct i2c_adapter *adapter = platform_get_drvdata(dev);
+ int rc;
+
+ rc = i2c_del_adapter(adapter);
+ platform_set_drvdata(dev, NULL);
+
+ kfree(adapter);
+
+ return rc;
+}
+
+static struct platform_driver tile_i2c_driver = {
+ .driver = {
+ .name = DRV_NAME,
+ .owner = THIS_MODULE,
+ },
+ .probe = tile_i2c_probe,
+ .remove = __devexit_p(tile_i2c_remove),
+};
+
+/*
+ * Driver init routine.
+ */
+static int __init tile_i2c_init(void)
+{
+ int err;
+
+ err = platform_driver_register(&tile_i2c_driver);
+ if (err)
+ return err;
+
+ i2c_platform_device =
+ platform_device_register_simple(DRV_NAME, -1, NULL, 0);
+ if (IS_ERR(i2c_platform_device)) {
+ err = PTR_ERR(i2c_platform_device);
+ goto unreg_platform_driver;
+ }
+
+ return 0;
+
+unreg_platform_driver:
+ platform_driver_unregister(&tile_i2c_driver);
+ return err;
+}
+
+/*
+ * Driver cleanup routine.
+ */
+static void __exit tile_i2c_exit(void)
+{
+ platform_driver_unregister(&tile_i2c_driver);
+}
+
+module_init(tile_i2c_init);
+module_exit(tile_i2c_exit);
--
1.6.5.2
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