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#include <linux/module.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/kernel.h> /* printk() */
#include <linux/slab.h> /* kmalloc() */
#include <linux/fs.h> /* everything... */
#include <linux/errno.h> /* error codes */
#include <linux/types.h> /* size_t */
#include <linux/cdev.h>
#include <linux/uaccess.h> /* copy_*_user */
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include "kpc_dma_driver.h"
#include "uapi.h"
/********** Helper Functions **********/
static inline
unsigned int count_pages(unsigned long iov_base, size_t iov_len)
{
unsigned long first = (iov_base & PAGE_MASK) >> PAGE_SHIFT;
unsigned long last = ((iov_base + iov_len - 1) & PAGE_MASK) >> PAGE_SHIFT;
return last - first + 1;
}
static inline
unsigned int count_parts_for_sge(struct scatterlist *sg)
{
return DIV_ROUND_UP(sg_dma_len(sg), 0x80000);
}
/********** Transfer Helpers **********/
static int kpc_dma_transfer(struct dev_private_data *priv,
unsigned long iov_base, size_t iov_len)
{
unsigned int i = 0;
long rv = 0;
struct kpc_dma_device *ldev;
struct aio_cb_data *acd;
DECLARE_COMPLETION_ONSTACK(done);
u32 desc_needed = 0;
struct scatterlist *sg;
u32 num_descrs_avail;
struct kpc_dma_descriptor *desc;
unsigned int pcnt;
unsigned int p;
u64 card_addr;
u64 dma_addr;
u64 user_ctl;
ldev = priv->ldev;
acd = kzalloc(sizeof(*acd), GFP_KERNEL);
if (!acd) {
dev_err(&priv->ldev->pldev->dev, "Couldn't kmalloc space for for the aio data\n");
return -ENOMEM;
}
memset(acd, 0x66, sizeof(struct aio_cb_data));
acd->priv = priv;
acd->ldev = priv->ldev;
acd->cpl = &done;
acd->flags = 0;
acd->len = iov_len;
acd->page_count = count_pages(iov_base, iov_len);
// Allocate an array of page pointers
acd->user_pages = kcalloc(acd->page_count, sizeof(struct page *),
GFP_KERNEL);
if (!acd->user_pages) {
dev_err(&priv->ldev->pldev->dev, "Couldn't kmalloc space for for the page pointers\n");
rv = -ENOMEM;
goto err_alloc_userpages;
}
// Lock the user buffer pages in memory, and hold on to the page pointers (for the sglist)
mmap_read_lock(current->mm); /* get memory map semaphore */
rv = get_user_pages(iov_base, acd->page_count, FOLL_TOUCH | FOLL_WRITE | FOLL_GET, acd->user_pages, NULL);
mmap_read_unlock(current->mm); /* release the semaphore */
if (rv != acd->page_count) {
dev_err(&priv->ldev->pldev->dev, "Couldn't get_user_pages (%ld)\n", rv);
goto err_get_user_pages;
}
// Allocate and setup the sg_table (scatterlist entries)
rv = sg_alloc_table_from_pages(&acd->sgt, acd->user_pages, acd->page_count, iov_base & (PAGE_SIZE - 1), iov_len, GFP_KERNEL);
if (rv) {
dev_err(&priv->ldev->pldev->dev, "Couldn't alloc sg_table (%ld)\n", rv);
goto err_alloc_sg_table;
}
// Setup the DMA mapping for all the sg entries
acd->mapped_entry_count = dma_map_sg(&ldev->pldev->dev, acd->sgt.sgl, acd->sgt.nents, ldev->dir);
if (acd->mapped_entry_count <= 0) {
dev_err(&priv->ldev->pldev->dev, "Couldn't dma_map_sg (%d)\n", acd->mapped_entry_count);
goto err_dma_map_sg;
}
// Calculate how many descriptors are actually needed for this transfer.
for_each_sg(acd->sgt.sgl, sg, acd->mapped_entry_count, i) {
desc_needed += count_parts_for_sge(sg);
}
lock_engine(ldev);
// Figoure out how many descriptors are available and return an error if there aren't enough
num_descrs_avail = count_descriptors_available(ldev);
dev_dbg(&priv->ldev->pldev->dev, " mapped_entry_count = %d num_descrs_needed = %d num_descrs_avail = %d\n", acd->mapped_entry_count, desc_needed, num_descrs_avail);
if (desc_needed >= ldev->desc_pool_cnt) {
dev_warn(&priv->ldev->pldev->dev, " mapped_entry_count = %d num_descrs_needed = %d num_descrs_avail = %d TOO MANY to ever complete!\n", acd->mapped_entry_count, desc_needed, num_descrs_avail);
rv = -EAGAIN;
goto err_descr_too_many;
}
if (desc_needed > num_descrs_avail) {
dev_warn(&priv->ldev->pldev->dev, " mapped_entry_count = %d num_descrs_needed = %d num_descrs_avail = %d Too many to complete right now.\n", acd->mapped_entry_count, desc_needed, num_descrs_avail);
rv = -EMSGSIZE;
goto err_descr_too_many;
}
// Loop through all the sg table entries and fill out a descriptor for each one.
desc = ldev->desc_next;
card_addr = acd->priv->card_addr;
for_each_sg(acd->sgt.sgl, sg, acd->mapped_entry_count, i) {
pcnt = count_parts_for_sge(sg);
for (p = 0 ; p < pcnt ; p++) {
// Fill out the descriptor
BUG_ON(!desc);
clear_desc(desc);
if (p != pcnt - 1)
desc->DescByteCount = 0x80000;
else
desc->DescByteCount = sg_dma_len(sg) - (p * 0x80000);
desc->DescBufferByteCount = desc->DescByteCount;
desc->DescControlFlags |= DMA_DESC_CTL_IRQONERR;
if (i == 0 && p == 0)
desc->DescControlFlags |= DMA_DESC_CTL_SOP;
if (i == acd->mapped_entry_count - 1 && p == pcnt - 1)
desc->DescControlFlags |= DMA_DESC_CTL_EOP | DMA_DESC_CTL_IRQONDONE;
desc->DescCardAddrLS = (card_addr & 0xFFFFFFFF);
desc->DescCardAddrMS = (card_addr >> 32) & 0xF;
card_addr += desc->DescByteCount;
dma_addr = sg_dma_address(sg) + (p * 0x80000);
desc->DescSystemAddrLS = (dma_addr & 0x00000000FFFFFFFFUL) >> 0;
desc->DescSystemAddrMS = (dma_addr & 0xFFFFFFFF00000000UL) >> 32;
user_ctl = acd->priv->user_ctl;
if (i == acd->mapped_entry_count - 1 && p == pcnt - 1)
user_ctl = acd->priv->user_ctl_last;
desc->DescUserControlLS = (user_ctl & 0x00000000FFFFFFFFUL) >> 0;
desc->DescUserControlMS = (user_ctl & 0xFFFFFFFF00000000UL) >> 32;
if (i == acd->mapped_entry_count - 1 && p == pcnt - 1)
desc->acd = acd;
dev_dbg(&priv->ldev->pldev->dev, " Filled descriptor %p (acd = %p)\n", desc, desc->acd);
ldev->desc_next = desc->Next;
desc = desc->Next;
}
}
// Send the filled descriptors off to the hardware to process!
SetEngineSWPtr(ldev, ldev->desc_next);
unlock_engine(ldev);
rv = wait_for_completion_interruptible(&done);
/*
* If the user aborted (rv == -ERESTARTSYS), we're no longer responsible
* for cleaning up the acd
*/
if (rv == -ERESTARTSYS)
acd->cpl = NULL;
if (rv == 0) {
rv = acd->len;
kfree(acd);
}
return rv;
err_descr_too_many:
unlock_engine(ldev);
dma_unmap_sg(&ldev->pldev->dev, acd->sgt.sgl, acd->sgt.nents, ldev->dir);
sg_free_table(&acd->sgt);
err_dma_map_sg:
err_alloc_sg_table:
for (i = 0 ; i < acd->page_count ; i++)
put_page(acd->user_pages[i]);
err_get_user_pages:
kfree(acd->user_pages);
err_alloc_userpages:
kfree(acd);
dev_dbg(&priv->ldev->pldev->dev, "%s returning with error %ld\n", __func__, rv);
return rv;
}
void transfer_complete_cb(struct aio_cb_data *acd, size_t xfr_count, u32 flags)
{
unsigned int i;
BUG_ON(!acd);
BUG_ON(!acd->user_pages);
BUG_ON(!acd->sgt.sgl);
BUG_ON(!acd->ldev);
BUG_ON(!acd->ldev->pldev);
for (i = 0 ; i < acd->page_count ; i++) {
if (!PageReserved(acd->user_pages[i]))
set_page_dirty(acd->user_pages[i]);
}
dma_unmap_sg(&acd->ldev->pldev->dev, acd->sgt.sgl, acd->sgt.nents, acd->ldev->dir);
for (i = 0 ; i < acd->page_count ; i++)
put_page(acd->user_pages[i]);
sg_free_table(&acd->sgt);
kfree(acd->user_pages);
acd->flags = flags;
if (acd->cpl) {
complete(acd->cpl);
} else {
/*
* There's no completion, so we're responsible for cleaning up
* the acd
*/
kfree(acd);
}
}
/********** Fileops **********/
static
int kpc_dma_open(struct inode *inode, struct file *filp)
{
struct dev_private_data *priv;
struct kpc_dma_device *ldev = kpc_dma_lookup_device(iminor(inode));
if (!ldev)
return -ENODEV;
if (!atomic_dec_and_test(&ldev->open_count)) {
atomic_inc(&ldev->open_count);
return -EBUSY; /* already open */
}
priv = kzalloc(sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
priv->ldev = ldev;
filp->private_data = priv;
return 0;
}
static
int kpc_dma_close(struct inode *inode, struct file *filp)
{
struct kpc_dma_descriptor *cur;
struct dev_private_data *priv = (struct dev_private_data *)filp->private_data;
struct kpc_dma_device *eng = priv->ldev;
lock_engine(eng);
stop_dma_engine(eng);
cur = eng->desc_completed->Next;
while (cur != eng->desc_next) {
dev_dbg(&eng->pldev->dev, "Aborting descriptor %p (acd = %p)\n", cur, cur->acd);
if (cur->DescControlFlags & DMA_DESC_CTL_EOP) {
if (cur->acd)
transfer_complete_cb(cur->acd, 0, ACD_FLAG_ABORT);
}
clear_desc(cur);
eng->desc_completed = cur;
cur = cur->Next;
}
start_dma_engine(eng);
unlock_engine(eng);
atomic_inc(&priv->ldev->open_count); /* release the device */
kfree(priv);
return 0;
}
static
ssize_t kpc_dma_read(struct file *filp, char __user *user_buf, size_t count, loff_t *ppos)
{
struct dev_private_data *priv = (struct dev_private_data *)filp->private_data;
if (priv->ldev->dir != DMA_FROM_DEVICE)
return -EMEDIUMTYPE;
return kpc_dma_transfer(priv, (unsigned long)user_buf, count);
}
static
ssize_t kpc_dma_write(struct file *filp, const char __user *user_buf, size_t count, loff_t *ppos)
{
struct dev_private_data *priv = (struct dev_private_data *)filp->private_data;
if (priv->ldev->dir != DMA_TO_DEVICE)
return -EMEDIUMTYPE;
return kpc_dma_transfer(priv, (unsigned long)user_buf, count);
}
static
long kpc_dma_ioctl(struct file *filp, unsigned int ioctl_num, unsigned long ioctl_param)
{
struct dev_private_data *priv = (struct dev_private_data *)filp->private_data;
switch (ioctl_num) {
case KND_IOCTL_SET_CARD_ADDR:
priv->card_addr = ioctl_param; return priv->card_addr;
case KND_IOCTL_SET_USER_CTL:
priv->user_ctl = ioctl_param; return priv->user_ctl;
case KND_IOCTL_SET_USER_CTL_LAST:
priv->user_ctl_last = ioctl_param; return priv->user_ctl_last;
case KND_IOCTL_GET_USER_STS:
return priv->user_sts;
}
return -ENOTTY;
}
const struct file_operations kpc_dma_fops = {
.owner = THIS_MODULE,
.open = kpc_dma_open,
.release = kpc_dma_close,
.read = kpc_dma_read,
.write = kpc_dma_write,
.unlocked_ioctl = kpc_dma_ioctl,
};
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