cregit-Linux how code gets into the kernel

Release 4.14 drivers/firewire/nosy.c

Directory: drivers/firewire
/*
 * nosy - Snoop mode driver for TI PCILynx 1394 controllers
 * Copyright (C) 2002-2007 Kristian Høgsberg
 *
 * 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include <linux/device.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/kref.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/pci.h>
#include <linux/poll.h>
#include <linux/sched.h> /* required for linux/wait.h */
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/time64.h>
#include <linux/timex.h>
#include <linux/uaccess.h>
#include <linux/wait.h>
#include <linux/dma-mapping.h>
#include <linux/atomic.h>
#include <asm/byteorder.h>

#include "nosy.h"
#include "nosy-user.h"


#define TCODE_PHY_PACKET		0x10

#define PCI_DEVICE_ID_TI_PCILYNX	0x8000


static char driver_name[] = KBUILD_MODNAME;

/* this is the physical layout of a PCL, its size is 128 bytes */

struct pcl {
	
__le32 next;
	
__le32 async_error_next;
	
u32 user_data;
	
__le32 pcl_status;
	
__le32 remaining_transfer_count;
	
__le32 next_data_buffer;
	struct {
		
__le32 control;
		
__le32 pointer;
	
} buffer[13];
};


struct packet {
	
unsigned int length;
	
char data[0];
};


struct packet_buffer {
	
char *data;
	
size_t capacity;
	

long total_packet_count, lost_packet_count;
	
atomic_t size;
	

struct packet *head, *tail;
	
wait_queue_head_t wait;
};


struct pcilynx {
	
struct pci_dev *pci_device;
	
__iomem char *registers;

	

struct pcl *rcv_start_pcl, *rcv_pcl;
	
__le32 *rcv_buffer;

	


dma_addr_t rcv_start_pcl_bus, rcv_pcl_bus, rcv_buffer_bus;

	
spinlock_t client_list_lock;
	
struct list_head client_list;

	
struct miscdevice misc;
	
struct list_head link;
	
struct kref kref;
};


static inline struct pcilynx * lynx_get(struct pcilynx *lynx) { kref_get(&lynx->kref); return lynx; }

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static void lynx_release(struct kref *kref) { kfree(container_of(kref, struct pcilynx, kref)); }

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static inline void lynx_put(struct pcilynx *lynx) { kref_put(&lynx->kref, lynx_release); }

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struct client { struct pcilynx *lynx; u32 tcode_mask; struct packet_buffer buffer; struct list_head link; }; static DEFINE_MUTEX(card_mutex); static LIST_HEAD(card_list);
static int packet_buffer_init(struct packet_buffer *buffer, size_t capacity) { buffer->data = kmalloc(capacity, GFP_KERNEL); if (buffer->data == NULL) return -ENOMEM; buffer->head = (struct packet *) buffer->data; buffer->tail = (struct packet *) buffer->data; buffer->capacity = capacity; buffer->lost_packet_count = 0; atomic_set(&buffer->size, 0); init_waitqueue_head(&buffer->wait); return 0; }

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static void packet_buffer_destroy(struct packet_buffer *buffer) { kfree(buffer->data); }

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static int packet_buffer_get(struct client *client, char __user *data, size_t user_length) { struct packet_buffer *buffer = &client->buffer; size_t length; char *end; if (wait_event_interruptible(buffer->wait, atomic_read(&buffer->size) > 0) || list_empty(&client->lynx->link)) return -ERESTARTSYS; if (atomic_read(&buffer->size) == 0) return -ENODEV; /* FIXME: Check length <= user_length. */ end = buffer->data + buffer->capacity; length = buffer->head->length; if (&buffer->head->data[length] < end) { if (copy_to_user(data, buffer->head->data, length)) return -EFAULT; buffer->head = (struct packet *) &buffer->head->data[length]; } else { size_t split = end - buffer->head->data; if (copy_to_user(data, buffer->head->data, split)) return -EFAULT; if (copy_to_user(data + split, buffer->data, length - split)) return -EFAULT; buffer->head = (struct packet *) &buffer->data[length - split]; } /* * Decrease buffer->size as the last thing, since this is what * keeps the interrupt from overwriting the packet we are * retrieving from the buffer. */ atomic_sub(sizeof(struct packet) + length, &buffer->size); return length; }

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static void packet_buffer_put(struct packet_buffer *buffer, void *data, size_t length) { char *end; buffer->total_packet_count++; if (buffer->capacity < atomic_read(&buffer->size) + sizeof(struct packet) + length) { buffer->lost_packet_count++; return; } end = buffer->data + buffer->capacity; buffer->tail->length = length; if (&buffer->tail->data[length] < end) { memcpy(buffer->tail->data, data, length); buffer->tail = (struct packet *) &buffer->tail->data[length]; } else { size_t split = end - buffer->tail->data; memcpy(buffer->tail->data, data, split); memcpy(buffer->data, data + split, length - split); buffer->tail = (struct packet *) &buffer->data[length - split]; } /* Finally, adjust buffer size and wake up userspace reader. */ atomic_add(sizeof(struct packet) + length, &buffer->size); wake_up_interruptible(&buffer->wait); }

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static inline void reg_write(struct pcilynx *lynx, int offset, u32 data) { writel(data, lynx->registers + offset); }

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static inline u32 reg_read(struct pcilynx *lynx, int offset) { return readl(lynx->registers + offset); }

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static inline void reg_set_bits(struct pcilynx *lynx, int offset, u32 mask) { reg_write(lynx, offset, (reg_read(lynx, offset) | mask)); }

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/* * Maybe the pcl programs could be set up to just append data instead * of using a whole packet. */
static inline void run_pcl(struct pcilynx *lynx, dma_addr_t pcl_bus, int dmachan) { reg_write(lynx, DMA0_CURRENT_PCL + dmachan * 0x20, pcl_bus); reg_write(lynx, DMA0_CHAN_CTRL + dmachan * 0x20, DMA_CHAN_CTRL_ENABLE | DMA_CHAN_CTRL_LINK); }

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static int set_phy_reg(struct pcilynx *lynx, int addr, int val) { if (addr > 15) { dev_err(&lynx->pci_device->dev, "PHY register address %d out of range\n", addr); return -1; } if (val > 0xff) { dev_err(&lynx->pci_device->dev, "PHY register value %d out of range\n", val); return -1; } reg_write(lynx, LINK_PHY, LINK_PHY_WRITE | LINK_PHY_ADDR(addr) | LINK_PHY_WDATA(val)); return 0; }

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static int nosy_open(struct inode *inode, struct file *file) { int minor = iminor(inode); struct client *client; struct pcilynx *tmp, *lynx = NULL; mutex_lock(&card_mutex); list_for_each_entry(tmp, &card_list, link) if (tmp->misc.minor == minor) { lynx = lynx_get(tmp); break; } mutex_unlock(&card_mutex); if (lynx == NULL) return -ENODEV; client = kmalloc(sizeof *client, GFP_KERNEL); if (client == NULL) goto fail; client->tcode_mask = ~0; client->lynx = lynx; INIT_LIST_HEAD(&client->link); if (packet_buffer_init(&client->buffer, 128 * 1024) < 0) goto fail; file->private_data = client; return nonseekable_open(inode, file); fail: kfree(client); lynx_put(lynx); return -ENOMEM; }

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static int nosy_release(struct inode *inode, struct file *file) { struct client *client = file->private_data; struct pcilynx *lynx = client->lynx; spin_lock_irq(&lynx->client_list_lock); list_del_init(&client->link); spin_unlock_irq(&lynx->client_list_lock); packet_buffer_destroy(&client->buffer); kfree(client); lynx_put(lynx); return 0; }

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static unsigned int nosy_poll(struct file *file, poll_table *pt) { struct client *client = file->private_data; unsigned int ret = 0; poll_wait(file, &client->buffer.wait, pt); if (atomic_read(&client->buffer.size) > 0) ret = POLLIN | POLLRDNORM; if (list_empty(&client->lynx->link)) ret |= POLLHUP; return ret; }

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static ssize_t nosy_read(struct file *file, char __user *buffer, size_t count, loff_t *offset) { struct client *client = file->private_data; return packet_buffer_get(client, buffer, count); }

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static long nosy_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { struct client *client = file->private_data; spinlock_t *client_list_lock = &client->lynx->client_list_lock; struct nosy_stats stats; switch (cmd) { case NOSY_IOC_GET_STATS: spin_lock_irq(client_list_lock); stats.total_packet_count = client->buffer.total_packet_count; stats.lost_packet_count = client->buffer.lost_packet_count; spin_unlock_irq(client_list_lock); if (copy_to_user((void __user *) arg, &stats, sizeof stats)) return -EFAULT; else return 0; case NOSY_IOC_START: spin_lock_irq(client_list_lock); list_add_tail(&client->link, &client->lynx->client_list); spin_unlock_irq(client_list_lock); return 0; case NOSY_IOC_STOP: spin_lock_irq(client_list_lock); list_del_init(&client->link); spin_unlock_irq(client_list_lock); return 0; case NOSY_IOC_FILTER: spin_lock_irq(client_list_lock); client->tcode_mask = arg; spin_unlock_irq(client_list_lock); return 0; default: return -EINVAL; /* Flush buffer, configure filter. */ } }

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static const struct file_operations nosy_ops = { .owner = THIS_MODULE, .read = nosy_read, .unlocked_ioctl = nosy_ioctl, .poll = nosy_poll, .open = nosy_open, .release = nosy_release, }; #define PHY_PACKET_SIZE 12 /* 1 payload, 1 inverse, 1 ack = 3 quadlets */
static void packet_irq_handler(struct pcilynx *lynx) { struct client *client; u32 tcode_mask, tcode, timestamp; size_t length; struct timespec64 ts64; /* FIXME: Also report rcv_speed. */ length = __le32_to_cpu(lynx->rcv_pcl->pcl_status) & 0x00001fff; tcode = __le32_to_cpu(lynx->rcv_buffer[1]) >> 4 & 0xf; ktime_get_real_ts64(&ts64); timestamp = ts64.tv_nsec / NSEC_PER_USEC; lynx->rcv_buffer[0] = (__force __le32)timestamp; if (length == PHY_PACKET_SIZE) tcode_mask = 1 << TCODE_PHY_PACKET; else tcode_mask = 1 << tcode; spin_lock(&lynx->client_list_lock); list_for_each_entry(client, &lynx->client_list, link) if (client->tcode_mask & tcode_mask) packet_buffer_put(&client->buffer, lynx->rcv_buffer, length + 4); spin_unlock(&lynx->client_list_lock); }

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static void bus_reset_irq_handler(struct pcilynx *lynx) { struct client *client; struct timespec64 ts64; u32 timestamp; ktime_get_real_ts64(&ts64); timestamp = ts64.tv_nsec / NSEC_PER_USEC; spin_lock(&lynx->client_list_lock); list_for_each_entry(client, &lynx->client_list, link) packet_buffer_put(&client->buffer, &timestamp, 4); spin_unlock(&lynx->client_list_lock); }

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static irqreturn_t irq_handler(int irq, void *device) { struct pcilynx *lynx = device; u32 pci_int_status; pci_int_status = reg_read(lynx, PCI_INT_STATUS); if (pci_int_status == ~0) /* Card was ejected. */ return IRQ_NONE; if ((pci_int_status & PCI_INT_INT_PEND) == 0) /* Not our interrupt, bail out quickly. */ return IRQ_NONE; if ((pci_int_status & PCI_INT_P1394_INT) != 0) { u32 link_int_status; link_int_status = reg_read(lynx, LINK_INT_STATUS); reg_write(lynx, LINK_INT_STATUS, link_int_status); if ((link_int_status & LINK_INT_PHY_BUSRESET) > 0) bus_reset_irq_handler(lynx); } /* Clear the PCI_INT_STATUS register only after clearing the * LINK_INT_STATUS register; otherwise the PCI_INT_P1394 will * be set again immediately. */ reg_write(lynx, PCI_INT_STATUS, pci_int_status); if ((pci_int_status & PCI_INT_DMA0_HLT) > 0) { packet_irq_handler(lynx); run_pcl(lynx, lynx->rcv_start_pcl_bus, 0); } return IRQ_HANDLED; }

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static void remove_card(struct pci_dev *dev) { struct pcilynx *lynx = pci_get_drvdata(dev); struct client *client; mutex_lock(&card_mutex); list_del_init(&lynx->link); misc_deregister(&lynx->misc); mutex_unlock(&card_mutex); reg_write(lynx, PCI_INT_ENABLE, 0); free_irq(lynx->pci_device->irq, lynx); spin_lock_irq(&lynx->client_list_lock); list_for_each_entry(client, &lynx->client_list, link) wake_up_interruptible(&client->buffer.wait); spin_unlock_irq(&lynx->client_list_lock); pci_free_consistent(lynx->pci_device, sizeof(struct pcl), lynx->rcv_start_pcl, lynx->rcv_start_pcl_bus); pci_free_consistent(lynx->pci_device, sizeof(struct pcl), lynx->rcv_pcl, lynx->rcv_pcl_bus); pci_free_consistent(lynx->pci_device, PAGE_SIZE, lynx->rcv_buffer, lynx->rcv_buffer_bus); iounmap(lynx->registers); pci_disable_device(dev); lynx_put(lynx); }

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#define RCV_BUFFER_SIZE (16 * 1024)
static int add_card(struct pci_dev *dev, const struct pci_device_id *unused) { struct pcilynx *lynx; u32 p, end; int ret, i; if (pci_set_dma_mask(dev, DMA_BIT_MASK(32))) { dev_err(&dev->dev, "DMA address limits not supported for PCILynx hardware\n"); return -ENXIO; } if (pci_enable_device(dev)) { dev_err(&dev->dev, "Failed to enable PCILynx hardware\n"); return -ENXIO; } pci_set_master(dev); lynx = kzalloc(sizeof *lynx, GFP_KERNEL); if (lynx == NULL) { dev_err(&dev->dev, "Failed to allocate control structure\n"); ret = -ENOMEM; goto fail_disable; } lynx->pci_device = dev; pci_set_drvdata(dev, lynx); spin_lock_init(&lynx->client_list_lock); INIT_LIST_HEAD(&lynx->client_list); kref_init(&lynx->kref); lynx->registers = ioremap_nocache(pci_resource_start(dev, 0), PCILYNX_MAX_REGISTER); if (lynx->registers == NULL) { dev_err(&dev->dev, "Failed to map registers\n"); ret = -ENOMEM; goto fail_deallocate_lynx; } lynx->rcv_start_pcl = pci_alloc_consistent(lynx->pci_device, sizeof(struct pcl), &lynx->rcv_start_pcl_bus); lynx->rcv_pcl = pci_alloc_consistent(lynx->pci_device, sizeof(struct pcl), &lynx->rcv_pcl_bus); lynx->rcv_buffer = pci_alloc_consistent(lynx->pci_device, RCV_BUFFER_SIZE, &lynx->rcv_buffer_bus); if (lynx->rcv_start_pcl == NULL || lynx->rcv_pcl == NULL || lynx->rcv_buffer == NULL) { dev_err(&dev->dev, "Failed to allocate receive buffer\n"); ret = -ENOMEM; goto fail_deallocate_buffers; } lynx->rcv_start_pcl->next = cpu_to_le32(lynx->rcv_pcl_bus); lynx->rcv_pcl->next = cpu_to_le32(PCL_NEXT_INVALID); lynx->rcv_pcl->async_error_next = cpu_to_le32(PCL_NEXT_INVALID); lynx->rcv_pcl->buffer[0].control = cpu_to_le32(PCL_CMD_RCV | PCL_BIGENDIAN | 2044); lynx->rcv_pcl->buffer[0].pointer = cpu_to_le32(lynx->rcv_buffer_bus + 4); p = lynx->rcv_buffer_bus + 2048; end = lynx->rcv_buffer_bus + RCV_BUFFER_SIZE; for (i = 1; p < end; i++, p += 2048) { lynx->rcv_pcl->buffer[i].control = cpu_to_le32(PCL_CMD_RCV | PCL_BIGENDIAN | 2048); lynx->rcv_pcl->buffer[i].pointer = cpu_to_le32(p); } lynx->rcv_pcl->buffer[i - 1].control |= cpu_to_le32(PCL_LAST_BUFF); reg_set_bits(lynx, MISC_CONTROL, MISC_CONTROL_SWRESET); /* Fix buggy cards with autoboot pin not tied low: */ reg_write(lynx, DMA0_CHAN_CTRL, 0); reg_write(lynx, DMA_GLOBAL_REGISTER, 0x00 << 24); #if 0 /* now, looking for PHY register set */ if ((get_phy_reg(lynx, 2) & 0xe0) == 0xe0) { lynx->phyic.reg_1394a = 1; PRINT(KERN_INFO, lynx->id, "found 1394a conform PHY (using extended register set)"); lynx->phyic.vendor = get_phy_vendorid(lynx); lynx->phyic.product = get_phy_productid(lynx); } else { lynx->phyic.reg_1394a = 0; PRINT(KERN_INFO, lynx->id, "found old 1394 PHY"); } #endif /* Setup the general receive FIFO max size. */ reg_write(lynx, FIFO_SIZES, 255); reg_set_bits(lynx, PCI_INT_ENABLE, PCI_INT_DMA_ALL); reg_write(lynx, LINK_INT_ENABLE, LINK_INT_PHY_TIME_OUT | LINK_INT_PHY_REG_RCVD | LINK_INT_PHY_BUSRESET | LINK_INT_IT_STUCK | LINK_INT_AT_STUCK | LINK_INT_SNTRJ | LINK_INT_TC_ERR | LINK_INT_GRF_OVER_FLOW | LINK_INT_ITF_UNDER_FLOW | LINK_INT_ATF_UNDER_FLOW); /* Disable the L flag in self ID packets. */ set_phy_reg(lynx, 4, 0); /* Put this baby into snoop mode */ reg_set_bits(lynx, LINK_CONTROL, LINK_CONTROL_SNOOP_ENABLE); run_pcl(lynx, lynx->rcv_start_pcl_bus, 0); if (request_irq(dev->irq, irq_handler, IRQF_SHARED, driver_name, lynx)) { dev_err(&dev->dev, "Failed to allocate shared interrupt %d\n", dev->irq); ret = -EIO; goto fail_deallocate_buffers;