PCIe driver that needs waaay to much contigious DMA buffer
thing.h
#ifndef thing_H
#define thing_H
#define DEVICE_NAME "thing"
#define DRIVER_NAME "thing"
struct context {
uint card; // cards probed
struct pci_dev *pdev; // pci dev
void *buf1; // DMA download data
dma_addr_t buf1_dma_handle; // physical address of the DMA download region
struct cdev cdev; // char dev
uint opens; // XXX do I really need to know this?
uint32_t pci_mem_start; // pci config space
uint32_t pci_mem_length; // pci config space
void __iomem *bar0_base_addr; // the BARs were mapped here
int irq; // our IRQ
};
static int thing_probe(struct pci_dev *, const struct pci_device_id *);
static void thing_remove(struct pci_dev *);
static int fops_open (struct inode *, struct file *);
static ssize_t fops_read(struct file *, char __user *, size_t, loff_t *);
static ssize_t fops_write(struct file *, const char __user *, size_t, loff_t *);
static irqreturn_t thing_isr(int, void *);
static int fops_release (struct inode *, struct file *);
#endif //thing_H
thing.c
#include <linux/cma.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/fs.h>
#include <linux/gfp.h>
#include <linux/init.h>
#include <linux/kernel.h> /* Needed for KERN_INFO */
#include <linux/mm.h>
#include <linux/module.h> /* Needed by all modules */
#include <linux/pci.h>
#include <stddef.h>
#include <linux/cdev.h>
#include <linux/uaccess.h>
#include <linux/delay.h>
#include "thing.h"
#define DEVICE_NAME "thing"
#define DRIVER_NAME "thing"
MODULE_LICENSE("GPL"); // The license type -- this affects available functionality
MODULE_AUTHOR("Tim Allen"); // The author -- visible when you use modinfo
MODULE_DESCRIPTION("thing accelerator Driver");
MODULE_VERSION("0.1"); // A version number to inform users
static const size_t dbsize = 16 * 1024;
static struct class *class;
static struct device *device_file;
static struct context *ctxs[8]; //up to 8 cards
// define which file operations are supported
struct file_operations fops = {
.owner = THIS_MODULE,
.llseek = NULL,
.read = fops_read,
.write = fops_write,
.poll = NULL,
.unlocked_ioctl = NULL,
.mmap = NULL, //mmap
.open = fops_open, //open
.flush = NULL,
.release = fops_release, //close
.fsync = NULL,
.fasync = NULL,
.lock = NULL,
};
static const struct pci_device_id pci_device_ids[] = {
{PCI_DEVICE(0x1002, 0x6610)}, // some GPU card I'm using for dev
{PCI_DEVICE(0x1234, 0x000a)}, // hsp card
{PCI_DEVICE(0x1234, 0x000b)}, // our card
{0, /* end of list */},
};
static struct pci_driver thing_driver = {
.name = DRIVER_NAME,
.id_table = pci_device_ids,
.probe = thing_probe,
.remove = thing_remove,
};
/** init is the entry point for the module
*
*/
static int __init thing_init(void) {
class = class_create(THIS_MODULE, "thing");
if(!class) {
printk (KERN_ERR "[%s:init] unable to create class device", DRIVER_NAME);
return -EIO;
}
if (pci_register_driver(&thing_driver) < 0) {
printk(KERN_ERR "[%s:init] unable to register", DRIVER_NAME);
return -EIO;
}
printk(KERN_INFO "[%s:init] driver registered", DRIVER_NAME);
return 0; // A non 0 return means init_module failed; module can't be loaded.
}
module_init(thing_init); // this macro registers the module entry point
/** a card has been inserted, time to set it up
*
*/
static int thing_probe(struct pci_dev *pdev, const struct pci_device_id *id) {
int err;
uint8_t byte = 0;
uint16_t word = 0;
uint32_t dword = 0;
char devfilename[255];
struct context *ctx;
static int cards = 0;
//begin filling out the context struct
ctx = kmalloc(sizeof (struct context), GFP_KERNEL);
memset(ctx, 0, sizeof (struct context));
ctxs[cards] = ctx; // store *ctx indexed by card probe order
pci_set_drvdata(pdev, (void*)ctx); // store *ctx indexed by pdev
ctx->card = cards++; // card number in arbitrary order
ctx->pdev = pdev;
err = pci_enable_device(pdev);
if (err) {
printk(KERN_ERR "[%s:probe] pci_enable_device returned %d", DRIVER_NAME, err);
return -ENODEV;
}
err = pci_request_region(pdev, 0, DRIVER_NAME);
if (err) {
printk(KERN_ERR "[%s:probe] request_region returned %d", DRIVER_NAME, err);
return -ENODEV;
}
// say some useless stuff about the card
pci_read_config_word(pdev, PCI_VENDOR_ID, &word);
printk(KERN_INFO "[%s:probe] PCI_VENDOR_ID: %4.4x", DRIVER_NAME, word);
pci_read_config_word(pdev, PCI_DEVICE_ID, &word);
printk(KERN_INFO "[%s:probe] PCI_DEVICE_ID: %4.4x", DRIVER_NAME, word);
pci_read_config_word(pdev, PCI_COMMAND, &word);
printk(KERN_INFO "[%s:probe] PCI_COMMAND: %4.4x", DRIVER_NAME, word);
pci_read_config_word(pdev, PCI_STATUS, &word);
printk(KERN_INFO "[%s:probe] PCI_STATUS: %4.4x", DRIVER_NAME, word);
pci_read_config_byte(pdev, PCI_REVISION_ID, &byte);
printk(KERN_INFO "[%s:probe] PCI_REVISION_ID: %2.2x", DRIVER_NAME, byte);
pci_read_config_byte(pdev, PCI_INTERRUPT_LINE, &byte);
printk(KERN_INFO "[%s:probe] PCI_INTERRUPT_LINE: %2.2x", DRIVER_NAME, byte);
pci_read_config_byte(pdev, PCI_INTERRUPT_PIN, &byte);
printk(KERN_INFO "[%s:probe] PCI_INTERRUPT_PIN: %2.2x", DRIVER_NAME, byte);
ctx->pci_mem_start = pci_resource_start(pdev, 0);
ctx->pci_mem_length = pci_resource_len(pdev, 0);
pci_read_config_dword(pdev, ctx->pci_mem_start, &dword);
printk(KERN_INFO "[%s:probe] device_info: %8.8x", DRIVER_NAME, dword);
pci_read_config_dword(pdev, ctx->pci_mem_start + 0x3c, &dword);
printk(KERN_INFO "[%s:probe] revision_number: %8.8x", DRIVER_NAME, dword);
ctx->bar0_base_addr = pci_iomap(pdev, 0, ctx->pci_mem_length); // map the BARs
printk(KERN_INFO "[%s:probe] bar0_base_addr: %p", DRIVER_NAME, ctx->bar0_base_addr);
// create the device file entry (/dev/thing)
snprintf(devfilename, sizeof devfilename, "thing%d", ctx->card);
device_file = device_create(class, NULL, MKDEV(810, ctx->card), 0, devfilename);
if(!device_file) {
printk (KERN_ERR "[%s:init] unable to create device class device", DRIVER_NAME);
return -EIO;
} else {
printk(KERN_INFO "[%s:probe] device %s created.", DRIVER_NAME, devfilename);
}
// set-up file ops
cdev_init(&ctx->cdev, &fops);
ctx->cdev.owner = THIS_MODULE;
ctx->cdev.ops = &fops;
err = cdev_add(&ctx->cdev, MKDEV(810, ctx->card), 1);
if (err) {
printk(KERN_INFO "[%s:probe] cdev_add failed with %d", DRIVER_NAME, err);
return -EIO;
}
// set-up the DMA buffers
err = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
if (err) {
printk(KERN_INFO "[%s:probe] dma_set_mask returned: %d", DRIVER_NAME, err);
return -EIO;
}
ctx->buf1 = dma_alloc_coherent(&pdev->dev, dbsize, &ctx->buf1_dma_handle, GFP_KERNEL);
if (!ctx->buf1) {
printk(KERN_ALERT "[%s:probe] failed to allocate coherent buffer", DRIVER_NAME);
return -EIO;
}
printk(KERN_INFO "[%s:probe] buf1 = %p buf1_dma_handle = %16.16llx ", DRIVER_NAME, ctx->buf1, ctx->buf1_dma_handle);
iowrite32(ctx->buf1_dma_handle, ctx->bar0_base_addr + 0x140); // tell card where to DMA from
// set-up IRQs
err = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_MSI);
printk(KERN_INFO "[%s:probe] pci_alloc_irq_vectors returns %d", DRIVER_NAME, err);
ctx->irq = pci_irq_vector(pdev, 0);
printk(KERN_INFO "[%s:probe] pci_irq_vector returns %d", DRIVER_NAME, ctx->irq);
err = request_irq(ctx->irq, &thing_isr, IRQF_SHARED, DRIVER_NAME, ctx);
printk(KERN_INFO "[%s:probe] request_irq returns %d", DRIVER_NAME, err);
// config done
dword = ioread32(ctx->bar0_base_addr + 0x00);
dword |= 0x10000000; // config_done
iowrite32(dword, ctx->bar0_base_addr + 0x00);
return 0; // A non 0 return means init_module failed; module can't be loaded.
}
/** open function - called when the device file is opened
*
*/
static int fops_open (struct inode *inode, struct file *filp) {
int major, minor;
int card;
struct context *ctx;
major = imajor(inode);
card = minor = iminor(inode);
ctx = ctxs[card];
printk(KERN_INFO "[%s:open] major = %d", DRIVER_NAME, major);
printk(KERN_INFO "[%s:open] minor = %d", DRIVER_NAME, minor);
ctx->opens++;
return 0;
}
/** read function - called when the device file is written to
*
*/
static ssize_t fops_read(struct file *filp, char __user *ubuf, size_t count, loff_t *offp) {
char kbuf[512];
uint c = 0; //position in kbuf, start at 0
int card; // the minor tells us which card
uint8_t byte = 0;
uint16_t word = 0;
uint32_t dword =0;
struct context *ctx;
card = iminor(filp->f_inode);
ctx = ctxs[card];
printk(KERN_INFO "[%s:read] minor = %d count = %ld *offp = %lld", DRIVER_NAME, card, count, *offp);
if (*offp)
return 0;
c += snprintf(&kbuf[c], sizeof kbuf, "read from card\t%d\n", card);
pci_read_config_word(ctx->pdev, PCI_VENDOR_ID, &word);
c += snprintf(&kbuf[c], sizeof kbuf, "PCI_VENDOR_ID:\t%4.4x\n", word);
pci_read_config_word(ctx->pdev, PCI_DEVICE_ID, &word);
c += snprintf(&kbuf[c], sizeof kbuf, "PCI_DEVICE_ID:\t%4.4x\n", word);
pci_read_config_word(ctx->pdev, PCI_COMMAND, &word);
c += snprintf(&kbuf[c], sizeof kbuf, "PCI_COMMAND:\t%4.4x\n", word);
pci_read_config_word(ctx->pdev, PCI_STATUS, &word);
c += snprintf(&kbuf[c], sizeof kbuf, "PCI_STATUS:\t%4.4x\n", word);
pci_read_config_byte(ctx->pdev, PCI_REVISION_ID, &byte);
c += snprintf(&kbuf[c], sizeof kbuf, "PCI_REV_ID:\t%2.2x\n", byte);
dword = ioread32(ctx->bar0_base_addr + 0x00);
c += snprintf(&kbuf[c], sizeof kbuf, "DEV NFO:\t%8.8x\n", dword);
dword = ioread32(ctx->bar0_base_addr + 0x04);
c += snprintf(&kbuf[c], sizeof kbuf, "IRQ PND:\t%8.8x\n", dword);
dword = ioread32(ctx->bar0_base_addr + 0x08);
c += snprintf(&kbuf[c], sizeof kbuf, "IRQ ACK:\t%8.8x\n", dword);
dword = ioread32(ctx->bar0_base_addr + 0x200);
c += snprintf(&kbuf[c], sizeof kbuf, "FPGA Status:\t%8.8x\n", dword);
copy_to_user(ubuf, kbuf, c);
*offp += c;
return c;
}
/** write function - called when the device file is written to
*
*/
static ssize_t fops_write(struct file *filp, const char __user *buffer, size_t length, loff_t * offset) {
int card; // the minor tells us which card
struct context *ctx;
card = iminor(filp->f_inode);
ctx = ctxs[card];
if (length%32)
printk(KERN_INFO "[%s:write] WARNING: not a mutiple of 32, sending anyway", DRIVER_NAME);
if (length > 16*32) {
printk(KERN_INFO "[%s:write] ERROR: maximum of 16", DRIVER_NAME);
return -EIO;
}
printk(KERN_INFO "[%s:write] sent %ld of 'em", DRIVER_NAME, length / 32);
memset(ctx->buf1, 0, dbsize);
copy_from_user(ctx->buf1, buffer, length);
iowrite32(length / 32, ctx->bar0_base_addr + 0x24); //number of 32B (256b) words to be downloaded to the card
iowrite32(0x80000000, ctx->bar0_base_addr + 0x20); //Data0 Buffer and trigger
ndelay(250);
iowrite32(0x00000000, ctx->bar0_base_addr + 0x20); //Data0 Buffer and trigger
return length;
}
/** Interrupt Service Routine
*
*/
static irqreturn_t thing_isr(int irq, void *lp) {
int irq_pending;
//XXX ctxs, uh no, need em sorted by irq
irq_pending = ioread32(ctxs[0]->bar0_base_addr + 0x04);
printk(KERN_INFO "[%s:isr] RXd IRQ %d, irq_pending = %2.2x\n", DRIVER_NAME, irq, irq_pending);
iowrite32(irq_pending, ctxs[0]->bar0_base_addr + 0x08);
return IRQ_HANDLED;
}
/** close function - called when the device file is closed
*
*/
static int fops_release (struct inode *inode, struct file *filp) {
int major, minor;
int card;
struct context *ctx;
major = imajor(inode);
card = minor = iminor(inode);
ctx = ctxs[card];
printk(KERN_INFO "[%s:release] major = %d", DRIVER_NAME, major);
printk(KERN_INFO "[%s:release] minor = %d", DRIVER_NAME, minor);
ctx->opens--;
return 0;
}
/** remove a card
*
*/
static void thing_remove(struct pci_dev *pdev) {
struct context *ctx;
ctx = (struct context*) pci_get_drvdata(pdev);
printk(KERN_INFO "[%s:remove] free coherent buffer", DRIVER_NAME);
if (ctx->buf1)
dma_free_coherent(&pdev->dev, dbsize, ctx->buf1, ctx->buf1_dma_handle);
free_irq(ctx->irq, ctx);
pci_free_irq_vectors(pdev);
device_destroy(class, MKDEV(810, ctx->card));
cdev_del(&ctx->cdev);
pci_release_region(pdev, 0);
pci_disable_device(pdev);
kfree(ctx);
}
/** prepare to be gone
*
*/
static void __exit thing_exit(void) {
pci_unregister_driver(&thing_driver);
printk(KERN_INFO "[%s:exit] driver unregistered", DRIVER_NAME);
class_unregister(class);
printk(KERN_INFO "[%s:exit] Goodbye world", DRIVER_NAME);
}
module_exit(thing_exit); // this macro registers the module exit point