diff options
Diffstat (limited to 'meta-amd-bsp/recipes-kernel/amd-spi/files/spirom.c')
-rw-r--r-- | meta-amd-bsp/recipes-kernel/amd-spi/files/spirom.c | 517 |
1 files changed, 0 insertions, 517 deletions
diff --git a/meta-amd-bsp/recipes-kernel/amd-spi/files/spirom.c b/meta-amd-bsp/recipes-kernel/amd-spi/files/spirom.c deleted file mode 100644 index 8547afd1..00000000 --- a/meta-amd-bsp/recipes-kernel/amd-spi/files/spirom.c +++ /dev/null @@ -1,517 +0,0 @@ -/***************************************************************************** -* -* spirom.c - SPI ROM client driver -* -* Copyright (c) 2014, Advanced Micro Devices, Inc. -* -* 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; if not, write to the Free Software -* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA -* -***************************************************************************/ -#include <linux/init.h> -#include <linux/module.h> -#include <linux/ioctl.h> -#include <linux/fs.h> -#include <linux/device.h> -#include <linux/err.h> -#include <linux/list.h> -#include <linux/errno.h> -#include <linux/mutex.h> -#include <linux/slab.h> -#include <linux/spi/spi.h> -#include <linux/pci.h> -#include <linux/delay.h> - -#include <linux/uaccess.h> - -#include "spirom.h" - -#define SPIROM_VERSION "0.2" - -/* - * SPI has a character major number assigned. We allocate minor numbers - * dynamically using a bitmask. You must use hotplug tools, such as udev - * (or mdev with busybox) to create and destroy the /dev/spiromB.C device - * nodes, since there is no fixed association of minor numbers with any - * particular SPI bus or device. - */ -#define SPIROM_MAJOR 153 /* assigned */ -#define N_SPI_MINORS 32 /* ... up to 256 */ - -#define SPI_BUS 0 -#define SPI_BUS_CS1 0 - -static unsigned long minors[N_SPI_MINORS / BITS_PER_LONG]; - - -struct spirom_data { - dev_t devt; - spinlock_t spi_lock; - struct spi_device *spi; - struct list_head device_entry; - struct completion done; - - struct mutex buf_lock; - unsigned users; -}; - -static LIST_HEAD(device_list); -static DEFINE_MUTEX(device_list_lock); - -/*-------------------------------------------------------------------------*/ - -/* - * We can't use the standard synchronous wrappers for file I/O; we - * need to protect against async removal of the underlying spi_device. - */ -static void spirom_complete(void *arg) -{ - complete(arg); -} - -static ssize_t -spirom_sync(struct spirom_data *spirom, struct spi_message *message) -{ - int status; - - message->complete = spirom_complete; - message->context = &spirom->done; - - spin_lock_irq(&spirom->spi_lock); - if (spirom->spi == NULL) - status = -ESHUTDOWN; - else - status = spi_async(spirom->spi, message); - spin_unlock_irq(&spirom->spi_lock); - - if (status == 0) { - /* - * There might be cases where the controller driver has been - * unloaded in the middle of a transaction. So we might end up - * in a situation where we will be waiting for an event which - * will never happen. So we provide a timeout of 1 second for - * situations like this. - */ - wait_for_completion_timeout(&spirom->done, HZ); - status = message->status; - if (status == 0) - status = message->actual_length; - } - return status; -} - -static int spirom_message(struct spirom_data *spirom, - struct spi_ioc_transfer *u_trans, unsigned long arg) -{ - struct spi_message msg; - struct spi_transfer *transfer; - u8 *buffer; - int status = u_trans->len; - - buffer = u_trans->buf; - spi_message_init(&msg); - - /* The very first spi_transfer will contain the command only */ - transfer = kzalloc(sizeof(struct spi_transfer), GFP_KERNEL); - if (!transfer) - return -ENOMEM; - - transfer->tx_buf = buffer; - transfer->len = 1; - buffer += transfer->len; - spi_message_add_tail(transfer, &msg); - - /* - * If the command expects an address as its argument, we populate - * it in the very next spi_transfer. - */ - if (u_trans->addr_present) { - transfer = kzalloc(sizeof(struct spi_transfer), GFP_KERNEL); - if (!transfer) - return -ENOMEM; - - transfer->tx_buf = buffer; - transfer->len = 3; // 3-byte address - buffer += transfer->len; - spi_message_add_tail(transfer, &msg); - } - - /* - * Next is data, which can have a maximum of 64-bytes, the size limited - * by the number of bytes that can stored in the controller FIFO. - */ - if (u_trans->len) { - transfer = kzalloc(sizeof(struct spi_transfer), GFP_KERNEL); - if (!transfer) - return -ENOMEM; - - if (u_trans->direction == TRANSMIT) - transfer->tx_buf = buffer; - else if (u_trans->direction == RECEIVE) - transfer->rx_buf = buffer; - - transfer->len = u_trans->len; - /* No need to increment buffer pointer */ - spi_message_add_tail(transfer, &msg); - } - - status = spirom_sync(spirom, &msg); - - if (u_trans->direction == RECEIVE) { - /* - * The received data should have been populated in - * u_trans->buf, so we just need to copy it into the - * user-space buffer. - */ - buffer = u_trans->buf; - if (u_trans->addr_present) { - buffer += 4; // 1-byte command and 3-byte address - if(__copy_to_user((u8 __user *) - (((struct spi_ioc_transfer *)arg)->buf) + 4, - buffer, u_trans->len)) { - status = -EFAULT; - } - } else { - buffer += 1; // 1-byte command only - if(__copy_to_user((u8 __user *) - (((struct spi_ioc_transfer *)arg)->buf) + 1, - buffer, u_trans->len)) { - status = -EFAULT; - } - } - } - - /* Done with everything, free the memory taken by spi_transfer */ - while (msg.transfers.next != &msg.transfers) { - transfer = list_entry(msg.transfers.next, struct spi_transfer, - transfer_list); - msg.transfers.next = transfer->transfer_list.next; - transfer->transfer_list.next->prev = &msg.transfers; - kfree(transfer); - } - - return status; -} - -static long -spirom_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) -{ - int err = 0; - int retval = 0; - struct spirom_data *spirom; - struct spi_device *spi; - u32 tmp; - struct spi_ioc_transfer *ioc; - - /* Check type and command number */ - if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC) - return -ENOTTY; - - /* Check access direction once here; don't repeat below. - * IOC_DIR is from the user perspective, while access_ok is - * from the kernel perspective; so they look reversed. - */ - if (_IOC_DIR(cmd) & _IOC_READ) - err = !access_ok((void __user *)arg, _IOC_SIZE(cmd)); - if (err == 0 && _IOC_DIR(cmd) & _IOC_WRITE) - err = !access_ok((void __user *)arg, _IOC_SIZE(cmd)); - if (err) - return -EFAULT; - - /* guard against device removal before, or while, - * we issue this ioctl. - */ - spirom = filp->private_data; - spin_lock_irq(&spirom->spi_lock); - spi = spi_dev_get(spirom->spi); - spin_unlock_irq(&spirom->spi_lock); - - if (spi == NULL) - return -ESHUTDOWN; - - /* use the buffer lock here for triple duty: - * - prevent I/O (from us) so calling spi_setup() is safe; - * - prevent concurrent SPI_IOC_WR_* from morphing - * data fields while SPI_IOC_RD_* reads them; - * - SPI_IOC_MESSAGE needs the buffer locked "normally". - */ - mutex_lock(&spirom->buf_lock); - - /* segmented and/or full-duplex I/O request */ - if (_IOC_NR(cmd) != _IOC_NR(SPI_IOC_MESSAGE(0)) || - _IOC_DIR(cmd) !=_IOC_WRITE) { - retval = -ENOTTY; - goto out; - } - - tmp = sizeof(struct spi_ioc_transfer); - - /* copy into scratch area */ - ioc = kzalloc(tmp, GFP_KERNEL); - if (!ioc) { - retval = -ENOMEM; - goto out; - } - if (__copy_from_user(ioc, (struct spi_ioc_transfer __user *)arg, - tmp)) { - kfree(ioc); - retval = -EFAULT; - goto out; - } - - /* translate to spi_message, execute */ - retval = spirom_message(spirom, ioc, arg); - kfree(ioc); - -out: - mutex_unlock(&spirom->buf_lock); - spi_dev_put(spi); - return retval; -} - -static int spirom_open(struct inode *inode, struct file *filp) -{ - struct spirom_data *spirom; - int status = -ENXIO; - - mutex_lock(&device_list_lock); - - list_for_each_entry(spirom, &device_list, device_entry) { - if (spirom->devt == inode->i_rdev) { - status = 0; - break; - } - } - if (status == 0) { - if (status == 0) { - spirom->users++; - filp->private_data = spirom; - nonseekable_open(inode, filp); - } - } else - pr_debug("spirom: nothing for minor %d\n", iminor(inode)); - - mutex_unlock(&device_list_lock); - return status; -} - -static int spirom_release(struct inode *inode, struct file *filp) -{ - struct spirom_data *spirom; - int status = 0; - - mutex_lock(&device_list_lock); - spirom = filp->private_data; - filp->private_data = NULL; - - /* last close? */ - spirom->users--; - if (!spirom->users) { - int dofree; - - /* ... after we unbound from the underlying device? */ - spin_lock_irq(&spirom->spi_lock); - dofree = (spirom->spi == NULL); - spin_unlock_irq(&spirom->spi_lock); - - if (dofree) - kfree(spirom); - } - mutex_unlock(&device_list_lock); - - return status; -} - -static const struct file_operations spirom_fops = { - .owner = THIS_MODULE, - .unlocked_ioctl = spirom_ioctl, - .open = spirom_open, - .release = spirom_release, -}; - -static int __init add_spi_device_to_bus(void) -{ - struct spi_master *spi_master; - struct spi_device *spi_device; - struct spi_board_info spi_info; - - spi_master = spi_busnum_to_master(SPI_BUS); - if (!spi_master) { - printk(KERN_ALERT "Please make sure to \'modprobe " - "spi_amd\' driver first\n"); - return -1; - } - memset(&spi_info, 0, sizeof(struct spi_board_info)); - - strlcpy(spi_info.modalias, "spirom", SPI_NAME_SIZE); - spi_info.bus_num = SPI_BUS; //Bus number of SPI master - spi_info.chip_select = SPI_BUS_CS1; //CS on which SPI device is connected - - spi_device = spi_new_device(spi_master, &spi_info); - if (!spi_device) - return -ENODEV; - - return 0; -} - -/*-------------------------------------------------------------------------*/ - -/* The main reason to have this class is to make mdev/udev create the - * /dev/spiromB.C character device nodes exposing our userspace API. - * It also simplifies memory management. - */ - -static struct class *spirom_class; - -/*-------------------------------------------------------------------------*/ - -static int spirom_probe(struct spi_device *spi) -{ - struct spirom_data *spirom; - int status; - unsigned long minor; - - /* Allocate driver data */ - spirom = kzalloc(sizeof(*spirom), GFP_KERNEL); - if (!spirom) - return -ENOMEM; - - /* Initialize the driver data */ - spirom->spi = spi; - spin_lock_init(&spirom->spi_lock); - mutex_init(&spirom->buf_lock); - - INIT_LIST_HEAD(&spirom->device_entry); - init_completion(&spirom->done); - - /* If we can allocate a minor number, hook up this device. - * Reusing minors is fine so long as udev or mdev is working. - */ - mutex_lock(&device_list_lock); - minor = find_first_zero_bit(minors, N_SPI_MINORS); - if (minor < N_SPI_MINORS) { - struct device *dev; - - spirom->devt = MKDEV(SPIROM_MAJOR, minor); - dev = device_create(spirom_class, &spi->dev, spirom->devt, - spirom, "spirom%d.%d", - spi->master->bus_num, spi->chip_select); - status = IS_ERR(dev) ? PTR_ERR(dev) : 0; - } else { - dev_dbg(&spi->dev, "no minor number available!\n"); - status = -ENODEV; - } - if (status == 0) { - set_bit(minor, minors); - list_add(&spirom->device_entry, &device_list); - } - mutex_unlock(&device_list_lock); - - if (status == 0) - spi_set_drvdata(spi, spirom); - else - kfree(spirom); - - return status; -} - -static int spirom_remove(struct spi_device *spi) -{ - struct spirom_data *spirom = spi_get_drvdata(spi); - - /* make sure ops on existing fds can abort cleanly */ - spin_lock_irq(&spirom->spi_lock); - spirom->spi = NULL; - spi_set_drvdata(spi, NULL); - spin_unlock_irq(&spirom->spi_lock); - - /* prevent new opens */ - mutex_lock(&device_list_lock); - list_del(&spirom->device_entry); - clear_bit(MINOR(spirom->devt), minors); - device_destroy(spirom_class, spirom->devt); - if (spirom->users == 0) - kfree(spirom); - mutex_unlock(&device_list_lock); - - return 0; -} - -static struct spi_driver spirom_spi = { - .driver = { - .name = "spirom", - .owner = THIS_MODULE, - }, - .probe = spirom_probe, - .remove = spirom_remove, - - /* NOTE: suspend/resume methods are not necessary here. - * We don't do anything except pass the requests to/from - * the underlying controller. The refrigerator handles - * most issues; the controller driver handles the rest. - */ -}; - -/*-------------------------------------------------------------------------*/ - -static int __init spirom_init(void) -{ - int status; - - pr_info("AMD SPIROM Driver v%s\n", SPIROM_VERSION); - - /* Claim our 256 reserved device numbers. Then register a class - * that will key udev/mdev to add/remove /dev nodes. Last, register - * the driver which manages those device numbers. - */ - BUILD_BUG_ON(N_SPI_MINORS > 256); - status = register_chrdev(SPIROM_MAJOR, "spi", &spirom_fops); - if (status < 0) - return status; - - spirom_class = class_create(THIS_MODULE, "spirom"); - if (IS_ERR(spirom_class)) { - unregister_chrdev(SPIROM_MAJOR, spirom_spi.driver.name); - return PTR_ERR(spirom_class); - } - - status = spi_register_driver(&spirom_spi); - if (status < 0) { - class_destroy(spirom_class); - unregister_chrdev(SPIROM_MAJOR, spirom_spi.driver.name); - } - - status = add_spi_device_to_bus(); - if (status < 0) { - spi_unregister_driver(&spirom_spi); - class_destroy(spirom_class); - unregister_chrdev(SPIROM_MAJOR, spirom_spi.driver.name); - } - - return status; -} -module_init(spirom_init); - -static void __exit spirom_exit(void) -{ - spi_unregister_driver(&spirom_spi); - class_destroy(spirom_class); - unregister_chrdev(SPIROM_MAJOR, spirom_spi.driver.name); -} -module_exit(spirom_exit); - -MODULE_AUTHOR("Arindam Nath <arindam.nath@amd.com>"); -MODULE_DESCRIPTION("User mode SPI ROM interface"); -MODULE_LICENSE("GPL v2"); -MODULE_ALIAS("spi:spirom"); |