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 <[email protected]> --- 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 <[email protected]> + * + * Borrowed heavily from original work by: + * Copyright (C) 2000 Philip Edelbrock <[email protected]> + */ + +#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 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
