- 根目录:
- drivers
- misc
- carma
- carma-fpga.c
/*
* CARMA DATA-FPGA Access Driver
*
* Copyright (c) 2009-2011 Ira W. Snyder <iws@ovro.caltech.edu>
*
* 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.
*/
/*
* FPGA Memory Dump Format
*
* FPGA #0 control registers (32 x 32-bit words)
* FPGA #1 control registers (32 x 32-bit words)
* FPGA #2 control registers (32 x 32-bit words)
* FPGA #3 control registers (32 x 32-bit words)
* SYSFPGA control registers (32 x 32-bit words)
* FPGA #0 correlation array (NUM_CORL0 correlation blocks)
* FPGA #1 correlation array (NUM_CORL1 correlation blocks)
* FPGA #2 correlation array (NUM_CORL2 correlation blocks)
* FPGA #3 correlation array (NUM_CORL3 correlation blocks)
*
* Each correlation array consists of:
*
* Correlation Data (2 x NUM_LAGSn x 32-bit words)
* Pipeline Metadata (2 x NUM_METAn x 32-bit words)
* Quantization Counters (2 x NUM_QCNTn x 32-bit words)
*
* The NUM_CORLn, NUM_LAGSn, NUM_METAn, and NUM_QCNTn values come from
* the FPGA configuration registers. They do not change once the FPGA's
* have been programmed, they only change on re-programming.
*/
/*
* Basic Description:
*
* This driver is used to capture correlation spectra off of the four data
* processing FPGAs. The FPGAs are often reprogrammed at runtime, therefore
* this driver supports dynamic enable/disable of capture while the device
* remains open.
*
* The nominal capture rate is 64Hz (every 15.625ms). To facilitate this fast
* capture rate, all buffers are pre-allocated to avoid any potentially long
* running memory allocations while capturing.
*
* There are two lists and one pointer which are used to keep track of the
* different states of data buffers.
*
* 1) free list
* This list holds all empty data buffers which are ready to receive data.
*
* 2) inflight pointer
* This pointer holds the currently inflight data buffer. This buffer is having
* data copied into it by the DMA engine.
*
* 3) used list
* This list holds data buffers which have been filled, and are waiting to be
* read by userspace.
*
* All buffers start life on the free list, then move successively to the
* inflight pointer, and then to the used list. After they have been read by
* userspace, they are moved back to the free list. The cycle repeats as long
* as necessary.
*
* It should be noted that all buffers are mapped and ready for DMA when they
* are on any of the three lists. They are only unmapped when they are in the
* process of being read by userspace.
*/
/*
* Notes on the IRQ masking scheme:
*
* The IRQ masking scheme here is different than most other hardware. The only
* way for the DATA-FPGAs to detect if the kernel has taken too long to copy
* the data is if the status registers are not cleared before the next
* correlation data dump is ready.
*
* The interrupt line is connected to the status registers, such that when they
* are cleared, the interrupt is de-asserted. Therein lies our problem. We need
* to schedule a long-running DMA operation and return from the interrupt
* handler quickly, but we cannot clear the status registers.
*
* To handle this, the system controller FPGA has the capability to connect the
* interrupt line to a user-controlled GPIO pin. This pin is driven high
* (unasserted) and left that way. To mask the interrupt, we change the
* interrupt source to the GPIO pin. Tada, we hid the interrupt. :)
*/
#include <linux/of_platform.h>
#include <linux/dma-mapping.h>
#include <linux/miscdevice.h>
#include <linux/interrupt.h>
#include <linux/dmaengine.h>
#include <linux/seq_file.h>
#include <linux/highmem.h>
#include <linux/debugfs.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/poll.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/kref.h>
#include <linux/io.h>
#include <media/videobuf-dma-sg.h>
/* system controller registers */
#define SYS_IRQ_SOURCE_CTL 0x24
#define SYS_IRQ_OUTPUT_EN 0x28
#define SYS_IRQ_OUTPUT_DATA 0x2C
#define SYS_IRQ_INPUT_DATA 0x30
#define SYS_FPGA_CONFIG_STATUS 0x44
/* GPIO IRQ line assignment */
#define IRQ_CORL_DONE 0x10
/* FPGA registers */
#define MMAP_REG_VERSION 0x00
#define MMAP_REG_CORL_CONF1 0x08
#define MMAP_REG_CORL_CONF2 0x0C
#define MMAP_REG_STATUS 0x48
#define SYS_FPGA_BLOCK 0xF0000000
#define DATA_FPGA_START 0x400000
#define DATA_FPGA_SIZE 0x80000
static const char drv_name[] = "carma-fpga";
#define NUM_FPGA 4
#define MIN_DATA_BUFS 8
#define MAX_DATA_BUFS 64
struct fpga_info {
unsigned int num_lag_ram;
unsigned int blk_size;
};
struct data_buf {
struct list_head entry;
struct videobuf_dmabuf vb;
size_t size;
};
struct fpga_device {
/* character device */
struct miscdevice miscdev;
struct device *dev;
struct mutex mutex;
/* reference count */
struct kref ref;
/* FPGA registers and information */
struct fpga_info info[NUM_FPGA];
void __iomem *regs;
int irq;
/* FPGA Physical Address/Size Information */
resource_size_t phys_addr;
size_t phys_size;
/* DMA structures */
struct sg_table corl_table;
unsigned int corl_nents;
struct dma_chan *chan;
/* Protection for all members below */
spinlock_t lock;
/* Device enable/disable flag */
bool enabled;
/* Correlation data buffers */
wait_queue_head_t wait;
struct list_head free;
struct list_head used;
struct data_buf *inflight;
/* Information about data buffers */
unsigned int num_dropped;
unsigned int num_buffers;
size_t bufsize;
struct dentry *dbg_entry;
};
struct fpga_reader {
struct fpga_device *priv;
struct data_buf *buf;
off_t buf_start;
};
static void fpga_device_release(struct kref *ref)
{
struct fpga_device *priv = container_of(ref, struct fpga_device, ref);
/* the last reader has exited, cleanup the last bits */
mutex_destroy(&priv->mutex);
kfree(priv);
}
/*
* Data Buffer Allocation Helpers
*/
/**
* data_free_buffer() - free a single data buffer and all allocated memory
* @buf: the buffer to free
*
* This will free all of the pages allocated to the given data buffer, and
* then free the structure itself
*/
static void data_free_buffer(struct data_buf *buf)
{
/* It is ok to free a NULL buffer */
if (!buf)
return;
/* free all memory */
videobuf_dma_free(&buf->vb);
kfree(buf);
}
/**
* data_alloc_buffer() - allocate and fill a data buffer with pages
* @bytes: the number of bytes required
*
* This allocates all space needed for a data buffer. It must be mapped before
* use in a DMA transaction using videobuf_dma_map().
*
* Returns NULL on failure
*/
static struct data_buf *data_alloc_buffer(const size_t bytes)
{
unsigned int nr_pages;
struct data_buf *buf;
int ret;
/* calculate the number of pages necessary */
nr_pages = DIV_ROUND_UP(bytes, PAGE_SIZE);
/* allocate the buffer structure */
buf = kzalloc(sizeof(*buf), GFP_KERNEL);
if (!buf)
goto out_return;
/* initialize internal fields */
INIT_LIST_HEAD(&buf->entry);
buf->size = bytes;
/* allocate the videobuf */
videobuf_dma_init(&buf->vb);
ret = videobuf_dma_init_kernel(&buf->vb, DMA_FROM_DEVICE, nr_pages);
if (ret)
goto out_free_buf;
return buf;
out_free_buf:
kfree(buf);
out_return:
return NULL;
}
/**
* data_free_buffers() - free all allocated buffers
* @priv: the driver's private data structure
*
* Free all buffers allocated by the driver (except those currently in the
* process of being read by userspace).
*
* LOCKING: must hold dev->mutex
* CONTEXT: user
*/
static void data_free_buffers(struct fpga_device *priv)
{
struct data_buf *buf, *tmp;
/* the device should be stopped, no DMA in progress */
BUG_ON(priv->inflight != NULL);
list_for_each_entry_safe(buf, tmp, &priv->free, entry) {
list_del_init(&buf->entry);
videobuf_dma_unmap(priv->dev, &buf->vb);
data_free_buffer(buf);
}
list_for_each_entry_safe(buf, tmp, &priv->used, entry) {
list_del_init(&buf->entry);
videobuf_dma_unmap(priv->dev, &buf->vb);
data_free_buffer(buf);
}
priv->num_buffers = 0;
priv->bufsize = 0;
}
/**
* data_alloc_buffers() - allocate 1 seconds worth of data buffers
* @priv: the driver's private data structure
*
* Allocate enough buffers for a whole second worth of data
*
* This routine will attempt to degrade nicely by succeeding even if a full
* second worth of data buffers could not be allocated, as long as a minimum
* number were allocated. In this case, it will print a message to the kernel
* log.
*
* The device must not be modifying any lists when this is called.
*
* CONTEXT: user
* LOCKING: must hold dev->mutex
*
* Returns 0 on success, -ERRNO otherwise
*/
static int data_alloc_buffers(struct fpga_device *priv)
{
struct data_buf *buf;
int i, ret;
for (i = 0; i < MAX_DATA_BUFS; i++) {
/* allocate a buffer */
buf = data_alloc_buffer(priv->bufsize);
if (!buf)
break;
/* map it for DMA */
ret = videobuf_dma_map(priv->dev, &buf->vb);
if (ret) {
data_free_buffer(buf);
break;
}
/* add it to the list of free buffers */
list_add_tail(&buf->entry, &priv->free);
priv->num_buffers++;
}
/* Make sure we allocated the minimum required number of buffers */
if (priv->num_buffers < MIN_DATA_BUFS) {
dev_err(priv->dev, "Unable to allocate enough data buffers\n");
data_free_buffers(priv);
return -ENOMEM;
}
/* Warn if we are running in a degraded state, but do not fail */
if (priv->num_buffers < MAX_DATA_BUFS) {
dev_warn(priv->dev,
"Unable to allocate %d buffers, using %d buffers instead\n",
MAX_DATA_BUFS, i);
}
return 0;
}
/*
* DMA Operations Helpers
*/
/**
* fpga_start_addr() - get the physical address a DATA-FPGA
* @priv: the driver's private data structure
* @fpga: the DATA-FPGA number (zero based)
*/
static dma_addr_t fpga_start_addr(struct fpga_device *priv, unsigned int fpga)
{
return priv->phys_addr + 0x400000 + (0x80000 * fpga);
}
/**
* fpga_block_addr() - get the physical address of a correlation data block
* @priv: the driver's private data structure
* @fpga: the DATA-FPGA number (zero based)
* @blknum: the correlation block number (zero based)
*/
static dma_addr_t fpga_block_addr(struct fpga_device *priv, unsigned int fpga,
unsigned int blknum)
{
return fpga_start_addr(priv, fpga) + (0x10000 * (1 + blknum));
}
#define REG_BLOCK_SIZE (32 * 4)
/**
* data_setup_corl_table() - create the scatterlist for correlation dumps
* @priv: the driver's private data structure
*
* Create the scatterlist for transferring a correlation dump from the
* DATA FPGAs. This structure will be reused for each buffer than needs
* to be filled with correlation data.
*
* Returns 0 on success, -ERRNO otherwise
*/
static int data_setup_corl_table(struct fpga_device *priv)
{
struct sg_table *table = &priv->corl_table;
struct scatterlist *sg;
struct fpga_info *info;
int i, j, ret;
/* Calculate the number of entries needed */
priv->corl_nents = (1 + NUM_FPGA) * REG_BLOCK_SIZE;
for (i = 0; i < NUM_FPGA; i++)
priv->corl_nents += priv->info[i].num_lag_ram;
/* Allocate the scatterlist table */
ret = sg_alloc_table(table, priv->corl_nents, GFP_KERNEL);
if (ret) {
dev_err(priv->dev, "unable to allocate DMA table\n");
return ret;
}
/* Add the DATA FPGA registers to the scatterlist */
sg = table->sgl;
for (i = 0; i < NUM_FPGA; i++) {
sg_dma_address(sg) = fpga_start_addr(priv, i);
sg_dma_len(sg) = REG_BLOCK_SIZE;
sg = sg_next(sg);
}
/* Add the SYS-FPGA registers to the scatterlist */
sg_dma_address(sg) = SYS_FPGA_BLOCK;
sg_dma_len(sg) = REG_BLOCK_SIZE;
sg = sg_next(sg);
/* Add the FPGA correlation data blocks to the scatterlist */
for (i = 0; i < NUM_FPGA; i++) {
info = &priv->info[i];
for (j = 0; j < info->num_lag_ram; j++) {
sg_dma_address(sg) = fpga_block_addr(priv, i, j);
sg_dma_len(sg) = info->blk_size;
sg = sg_next(sg);
}
}
/*
* All physical addresses and lengths are present in the structure
* now. It can be reused for every FPGA DATA interrupt
*/
return 0;
}
/*
* FPGA Register Access Helpers
*/
static void fpga_write_reg(struct fpga_device *priv, unsigned int fpga,
unsigned int reg, u32 val)
{
const int fpga_start = DATA_FPGA_START + (fpga * DATA_FPGA_SIZE);
iowrite32be(val, priv->regs + fpga_start + reg);
}
static u32 fpga_read_reg(struct fpga_device *priv, unsigned int fpga,
unsigned int reg)
{
const int fpga_start = DATA_FPGA_START + (fpga * DATA_FPGA_SIZE);
return ioread32be(priv->regs + fpga_start + reg);
}
/**
* data_calculate_bufsize() - calculate the data buffer size required
* @priv: the driver's private data structure
*
* Calculate the total buffer size needed to hold a single block
* of correlation data
*
* CONTEXT: user
*
* Returns 0 on success, -ERRNO otherwise
*/
static int data_calculate_bufsize(struct fpga_device *priv)
{
u32 num_corl, num_lags, num_meta, num_qcnt, num_pack;
u32 conf1, conf2, version;
u32 num_lag_ram, blk_size;
int i;
/* Each buffer starts with the 5 FPGA register areas */
priv->bufsize = (1 + NUM_FPGA) * REG_BLOCK_SIZE;
/* Read and store the configuration data for each FPGA */
for (i = 0; i < NUM_FPGA; i++) {
version = fpga_read_reg(priv, i, MMAP_REG_VERSION);
conf1 = fpga_read_reg(priv, i, MMAP_REG_CORL_CONF1);
conf2 = fpga_read_reg(priv, i, MMAP_REG_CORL_CONF2);
/* minor version 2 and later */
if ((version & 0x000000FF) >= 2) {
num_corl = (conf1 & 0x000000F0) >> 4;
num_pack = (conf1 & 0x00000F00) >> 8;
num_lags = (conf1 & 0x00FFF000) >> 12;
num_meta = (conf1 & 0x7F000000) >> 24;
num_qcnt = (conf2 & 0x00000FFF) >> 0;
} else {
num_corl = (conf1 & 0x000000F0) >> 4;
num_pack = 1; /* implied */
num_lags = (conf1 & 0x000FFF00) >> 8;
num_meta = (conf1 & 0x7FF00000) >> 20;
num_qcnt = (conf2 & 0x00000FFF) >> 0;
}
num_lag_ram = (num_corl + num_pack - 1) / num_pack;
blk_size = ((num_pack * num_lags) + num_meta + num_qcnt) * 8;
priv->info[i].num_lag_ram = num_lag_ram;
priv->info[i].blk_size = blk_size;
priv->bufsize += num_lag_ram * blk_size;
dev_dbg(priv->dev, "FPGA %d NUM_CORL: %d\n", i, num_corl);
dev_dbg(priv->dev, "FPGA %d NUM_PACK: %d\n", i, num_pack);
dev_dbg(priv->dev, "FPGA %d NUM_LAGS: %d\n", i, num_lags);
dev_dbg(priv->dev, "FPGA %d NUM_META: %d\n", i, num_meta);
dev_dbg(priv->dev, "FPGA %d NUM_QCNT: %d\n", i, num_qcnt);
dev_dbg(priv->dev, "FPGA %d BLK_SIZE: %d\n", i, blk_size);
}
dev_dbg(priv->dev, "TOTAL BUFFER SIZE: %zu bytes\n", priv->bufsize);
return 0;
}
/*
* Interrupt Handling
*/
/**
* data_disable_interrupts() - stop the device from generating interrupts
* @priv: the driver's private data structure
*
* Hide interrupts by switching to GPIO interrupt source
*
* LOCKING: must hold dev->lock
*/
static void data_disable_interrupts(struct fpga_device *priv)
{
/* hide the interrupt by switching the IRQ driver to GPIO */
iowrite32be(0x2F, priv->regs + SYS_IRQ_SOURCE_CTL);
}
/**
* data_enable_interrupts() - allow the device to generate interrupts
* @priv: the driver's private data structure
*
* Unhide interrupts by switching to the FPGA interrupt source. At the
* same time, clear the DATA-FPGA status registers.
*
* LOCKING: must hold dev->lock
*/
static void data_enable_interrupts(struct fpga_device *priv)
{
/* clear the actual FPGA corl_done interrupt */
fpga_write_reg(priv, 0, MMAP_REG_STATUS, 0x0);
fpga_write_reg(priv, 1, MMAP_REG_STATUS, 0x0);
fpga_write_reg(priv, 2, MMAP_REG_STATUS, 0x0);
fpga_write_reg(priv, 3, MMAP_REG_STATUS, 0x0);
/* flush the writes */
fpga_read_reg(priv, 0, MMAP_REG_STATUS);
fpga_read_reg(priv, 1, MMAP_REG_STATUS);
fpga_read_reg(priv, 2, MMAP_REG_STATUS);
fpga_read_reg(priv, 3, MMAP_REG_STATUS);
/* switch back to the external interrupt source */
iowrite32be(0x3F, priv->regs + SYS_IRQ_SOURCE_CTL);
}
/**
* data_dma_cb() - DMAEngine callback for DMA completion
* @data: the driver's private data structure
*
* Complete a DMA transfer from the DATA-FPGA's
*
* This is called via the DMA callback mechanism, and will handle moving the
* completed DMA transaction to the used list, and then wake any processes
* waiting for new data
*
* CONTEXT: any, softirq expected
*/
static void data_dma_cb(void *data)
{
struct fpga_device *priv = data;
unsigned long flags;
spin_lock_irqsave(&priv->lock, flags);
/* If there is no inflight buffer, we've got a bug */
BUG_ON(priv->inflight == NULL);
/* Move the inflight buffer onto the used list */
list_move_tail(&priv->inflight->entry, &priv->used);
priv->inflight = NULL;
/*
* If data dumping is still enabled, then clear the FPGA
* status registers and re-enable FPGA interrupts
*/
if (priv->enabled)
data_enable_interrupts(priv);
spin_unlock_irqrestore(&priv->lock, flags);
/*
* We've changed both the inflight and used lists, so we need
* to wake up any processes that are blocking for those events
*/
wake_up(&priv->wait);
}
/**
* data_submit_dma() - prepare and submit the required DMA to fill a buffer
* @priv: the driver's private data structure
* @buf: the data buffer
*
* Prepare and submit the necessary DMA transactions to fill a correlation
* data buffer.
*
* LOCKING: must hold dev->lock
* CONTEXT: hardirq only
*
* Returns 0 on success, -ERRNO otherwise
*/
static int data_submit_dma(struct fpga_device *priv, struct data_buf *buf)
{
struct scatterlist *dst_sg, *src_sg;
unsigned int dst_nents, src_nents;
struct dma_chan *chan = priv->chan;
struct dma_async_tx_descriptor *tx;
dma_cookie_t cookie;
dma_addr_t dst, src;
unsigned long dma_flags = DMA_COMPL_SKIP_DEST_UNMAP |
DMA_COMPL_SKIP_SRC_UNMAP;
dst_sg = buf->vb.sglist;
dst_nents = buf->vb.sglen;
src_sg = priv->corl_table.sgl;
src_nents = priv->corl_nents;
/*
* All buffers passed to this function should be ready and mapped
* for DMA already. Therefore, we don't need to do anything except
* submit it to the Freescale DMA Engine for processing
*/
/* setup the scatterlist to scatterlist transfer */
tx = chan->device->device_prep_dma_sg(chan,
dst_sg, dst_nents,
src_sg, src_nents,
0);
if (!tx) {
dev_err(priv->dev, "unable to prep scatterlist DMA\n");
return -ENOMEM;
}
/* submit the transaction to the DMA controller */
cookie = tx->tx_submit(tx);
if (dma_submit_error(cookie)) {
dev_err(priv->dev, "unable to submit scatterlist DMA\n");
return -ENOMEM;
}
/* Prepare the re-read of the SYS-FPGA block */
dst = sg_dma_address(dst_sg) + (NUM_FPGA * REG_BLOCK_SIZE);
src = SYS_FPGA_BLOCK;
tx = chan->device->device_prep_dma_memcpy(chan, dst, src,
REG_BLOCK_SIZE,
dma_flags);
if (!tx) {
dev_err(priv->dev, "unable to prep SYS-FPGA DMA\n");
return -ENOMEM;
}
/* Setup the callback */
tx->callback = data_dma_cb;
tx->callback_param = priv;
/* submit the transaction to the DMA controller */
cookie = tx->tx_submit(tx);
if (dma_submit_error(cookie)) {
dev_err(priv->dev, "unable to submit SYS-FPGA DMA\n");
return -ENOMEM;
}
return 0;
}
#define CORL_DONE 0x1
#define CORL_ERR 0x2
static irqreturn_t data_irq(int irq, void *dev_id)
{
struct fpga_device *priv = dev_id;
bool submitted = false;
struct data_buf *buf;
u32 status;
int i;
/* detect spurious interrupts via FPGA status */
for (i = 0; i < 4; i++) {
status = fpga_read_reg(priv, i, MMAP_REG_STATUS);
if (!(status & (CORL_DONE | CORL_ERR))) {
dev_err(priv->dev, "spurious irq detected (FPGA)\n");
return IRQ_NONE;
}
}
/* detect spurious interrupts via raw IRQ pin readback */
status = ioread32be(priv->regs + SYS_IRQ_INPUT_DATA);
if (status & IRQ_CORL_DONE) {
dev_err(priv->dev, "spurious irq detected (IRQ)\n");
return IRQ_NONE;
}
spin_lock(&priv->lock);
/*
* This is an error case that should never happen.
*
* If this driver has a bug and manages to re-enable interrupts while
* a DMA is in progress, then we will hit this statement and should
* start paying attention immediately.
*/
BUG_ON(priv->inflight != NULL);
/* hide the interrupt by switching the IRQ driver to GPIO */
data_disable_interrupts(priv);
/* If there are no free buffers, drop this data */
if (list_empty(&priv->free)) {
priv->num_dropped++;
goto out;
}
buf = list_first_entry(&priv->free, struct data_buf, entry);
list_del_init(&buf->entry);
BUG_ON(buf->size != priv->bufsize);
/* Submit a DMA transfer to get the correlation data */
if (data_submit_dma(priv, buf)) {
dev_err(priv->dev, "Unable to setup DMA transfer\n");
list_move_tail(&buf->entry, &priv->free);
goto out;
}
/* Save the buffer for the DMA callback */
priv->inflight = buf;
submitted = true;
/* Start the DMA Engine */
dma_async_issue_pending(priv->chan);
out:
/* If no DMA was submitted, re-enable interrupts */
if (!submitted)
data_enable_interrupts(priv);
spin_unlock(&priv->lock);
return IRQ_HANDLED;
}
/*
* Realtime Device Enable Helpers
*/
/**
* data_device_enable() - enable the device for buffered dumping
* @priv: the driver's private data structure
*
* Enable the device for buffered dumping. Allocates buffers and hooks up
* the interrupt handler. When this finishes, data will come pouring in.
*
* LOCKING: must hold dev->mutex
* CONTEXT: user context only
*
* Returns 0 on success, -ERRNO otherwise
*/
static int data_device_enable(struct fpga_device *priv)
{
bool enabled;
u32 val;
int ret;
/* multiple enables are safe: they do nothing */
spin_lock_irq(&priv->lock);
enabled = priv->enabled;
spin_unlock_irq(&priv->lock);
if (enabled)
return 0;
/* check that the FPGAs are programmed */
val = ioread32be(priv->regs + SYS_FPGA_CONFIG_STATUS);
if (!(val & (1 << 18))) {
dev_err(priv->dev, "DATA-FPGAs are not enabled\n");
return -ENODATA;
}
/* read the FPGAs to calculate the buffer size */
ret = data_calculate_bufsize(priv);
if (ret) {
dev_err(priv->dev, "unable to calculate buffer size\n");
goto out_error;
}
/* allocate the correlation data buffers */
ret = data_alloc_buffers(priv);
if (ret) {
dev_err(priv->dev, "unable to allocate buffers\n");
goto out_error;
}
/* setup the source scatterlist for dumping correlation data */
ret = data_setup_corl_table(priv);
if (ret) {
dev_err(priv->dev, "unable to setup correlation DMA table\n");
goto out_error;
}
/* prevent the FPGAs from generating interrupts */
data_disable_interrupts(priv);
/* hookup the irq handler */
ret = request_irq(priv->irq, data_irq, IRQF_SHARED, drv_name, priv);
if (ret) {
dev_err(priv->dev, "unable to request IRQ handler\n");
goto out_error;
}
/* allow the DMA callback to re-enable FPGA interrupts */
spin_lock_irq(&priv->lock);
priv->enabled = true;
spin_unlock_irq(&priv->lock);
/* allow the FPGAs to generate interrupts */
data_enable_interrupts(priv);
return 0;
out_error:
sg_free_table(&priv->corl_table);
priv->corl_nents = 0;
data_free_buffers(priv);
return ret;
}
/**
* data_device_disable() - disable the device for buffered dumping
* @priv: the driver's private data structure
*
* Disable the device for buffered dumping. Stops new DMA transactions from
* being generated, waits for all outstanding DMA to complete, and then frees
* all buffers.
*
* LOCKING: must hold dev->mutex
* CONTEXT: user only
*
* Returns 0 on success, -ERRNO otherwise
*/
static int data_device_disable(struct fpga_device *priv)
{
spin_lock_irq(&priv->lock);
/* allow multiple disable */
if (!priv->enabled) {
spin_unlock_irq(&priv->lock);
return 0;
}
/*
* Mark the device disabled
*
* This stops DMA callbacks from re-enabling interrupts
*/
priv->enabled = false;
/* prevent the FPGAs from generating interrupts */
data_disable_interrupts(priv);
/* wait until all ongoing DMA has finished */
while (priv->inflight != NULL) {
spin_unlock_irq(&priv->lock);
wait_event(priv->wait, priv->inflight == NULL);
spin_lock_irq(&priv->lock);
}
spin_unlock_irq(&priv->lock);
/* unhook the irq handler */
free_irq(priv->irq, priv);
/* free the correlation table */
sg_free_table(&priv->corl_table);
priv->corl_nents = 0;
/* free all buffers: the free and used lists are not being changed */
data_free_buffers(priv);
return 0;
}
/*
* DEBUGFS Interface
*/
#ifdef CONFIG_DEBUG_FS
/*
* Count the number of entries in the given list
*/
static unsigned int list_num_entries(struct list_head *list)
{
struct list_head *entry;
unsigned int ret = 0;
list_for_each(entry, list)
ret++;
return ret;
}
static int data_debug_show(struct seq_file *f, void *offset)
{
struct fpga_device *priv = f->private;
spin_lock_irq(&priv->lock);
seq_printf(f, "enabled: %d\n", priv->enabled);
seq_printf(f, "bufsize: %d\n", priv->bufsize);
seq_printf(f, "num_buffers: %d\n", priv->num_buffers);
seq_printf(f, "num_free: %d\n", list_num_entries(&priv->free));
seq_printf(f, "inflight: %d\n", priv->inflight != NULL);
seq_printf(f, "num_used: %d\n", list_num_entries(&priv->used));
seq_printf(f, "num_dropped: %d\n", priv->num_dropped);
spin_unlock_irq(&priv->lock);
return 0;
}
static int data_debug_open(struct inode *inode, struct file *file)
{
return single_open(file, data_debug_show, inode->i_private);
}
static const struct file_operations data_debug_fops = {
.owner = THIS_MODULE,
.open = data_debug_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static int data_debugfs_init(struct fpga_device *priv)
{
priv->dbg_entry = debugfs_create_file(drv_name, S_IRUGO, NULL, priv,
&data_debug_fops);
if (IS_ERR(priv->dbg_entry))
return PTR_ERR(priv->dbg_entry);
return 0;
}
static void data_debugfs_exit(struct fpga_device *priv)
{
debugfs_remove(priv->dbg_entry);
}
#else
static inline int data_debugfs_init(struct fpga_device *priv)
{
return 0;
}
static inline void data_debugfs_exit(struct fpga_device *priv)
{
}
#endif /* CONFIG_DEBUG_FS */
/*
* SYSFS Attributes
*/
static ssize_t data_en_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct fpga_device *priv = dev_get_drvdata(dev);
int ret;
spin_lock_irq(&priv->lock);
ret = snprintf(buf, PAGE_SIZE, "%u\n", priv->enabled);
spin_unlock_irq(&priv->lock);
return ret;
}
static ssize_t data_en_set(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct fpga_device *priv = dev_get_drvdata(dev);
unsigned long enable;
int ret;
ret = strict_strtoul(buf, 0, &enable);
if (ret) {
dev_err(priv->dev, "unable to parse enable input\n");
return -EINVAL;
}
/* protect against concurrent enable/disable */
ret = mutex_lock_interruptible(&priv->mutex);
if (ret)
return ret;
if (enable)
ret = data_device_enable(priv);
else
ret = data_device_disable(priv);
if (ret) {
dev_err(priv->dev, "device %s failed\n",
enable ? "enable" : "disable");
count = ret;
goto out_unlock;
}
out_unlock:
mutex_unlock(&priv->mutex);
return count;
}
static DEVICE_ATTR(enable, S_IWUSR | S_IRUGO, data_en_show, data_en_set);
static struct attribute *data_sysfs_attrs[] = {
&dev_attr_enable.attr,
NULL,
};
static const struct attribute_group rt_sysfs_attr_group = {
.attrs = data_sysfs_attrs,
};
/*
* FPGA Realtime Data Character Device
*/
static int data_open(struct inode *inode, struct file *filp)
{
/*
* The miscdevice layer puts our struct miscdevice into the
* filp->private_data field. We use this to find our private
* data and then overwrite it with our own private structure.
*/
struct fpga_device *priv = container_of(filp->private_data,
struct fpga_device, miscdev);
struct fpga_reader *reader;
int ret;
/* allocate private data */
reader = kzalloc(sizeof(*reader), GFP_KERNEL);
if (!reader)
return -ENOMEM;
reader->priv = priv;
reader->buf = NULL;
filp->private_data = reader;
ret = nonseekable_open(inode, filp);
if (ret) {
dev_err(priv->dev, "nonseekable-open failed\n");
kfree(reader);
return ret;
}
/*
* success, increase the reference count of the private data structure
* so that it doesn't disappear if the device is unbound
*/
kref_get(&priv->ref);
return 0;
}
static int data_release(struct inode *inode, struct file *filp)
{
struct fpga_reader *reader = filp->private_data;
struct fpga_device *priv = reader->priv;
/* free the per-reader structure */
data_free_buffer(reader->buf);
kfree(reader);
filp->private_data = NULL;
/* decrement our reference count to the private data */
kref_put(&priv->ref, fpga_device_release);
return 0;
}
static ssize_t data_read(struct file *filp, char __user *ubuf, size_t count,
loff_t *f_pos)
{
struct fpga_reader *reader = filp->private_data;
struct fpga_device *priv = reader->priv;
struct list_head *used = &priv->used;
bool drop_buffer = false;
struct data_buf *dbuf;
size_t avail;
void *data;
int ret;
/* check if we already have a partial buffer */
if (reader->buf) {
dbuf = reader->buf;
goto have_buffer;
}
spin_lock_irq(&priv->lock);
/* Block until there is at least one buffer on the used list */
while (list_empty(used)) {
spin_unlock_irq(&priv->lock);
if (filp->f_flags & O_NONBLOCK)
return -EAGAIN;
ret = wait_event_interruptible(priv->wait, !list_empty(used));
if (ret)
return ret;
spin_lock_irq(&priv->lock);
}
/* Grab the first buffer off of the used list */
dbuf = list_first_entry(used, struct data_buf, entry);
list_del_init(&dbuf->entry);
spin_unlock_irq(&priv->lock);
/* Buffers are always mapped: unmap it */
videobuf_dma_unmap(priv->dev, &dbuf->vb);
/* save the buffer for later */
reader->buf = dbuf;
reader->buf_start = 0;
have_buffer:
/* Get the number of bytes available */
avail = dbuf->size - reader->buf_start;
data = dbuf->vb.vaddr + reader->buf_start;
/* Get the number of bytes we can transfer */
count = min(count, avail);
/* Copy the data to the userspace buffer */
if (copy_to_user(ubuf, data, count))
return -EFAULT;
/* Update the amount of available space */
avail -= count;
/*
* If there is still some data available, save the buffer for the
* next userspace call to read() and return
*/
if (avail > 0) {
reader->buf_start += count;
reader->buf = dbuf;
return count;
}
/*
* Get the buffer ready to be reused for DMA
*
* If it fails, we pretend that the read never happed and return
* -EFAULT to userspace. The read will be retried.
*/
ret = videobuf_dma_map(priv->dev, &dbuf->vb);
if (ret) {
dev_err(priv->dev, "unable to remap buffer for DMA\n");
return -EFAULT;
}
/* Lock against concurrent enable/disable */
spin_lock_irq(&priv->lock);
/* the reader is finished with this buffer */
reader->buf = NULL;
/*
* One of two things has happened, the device is disabled, or the
* device has been reconfigured underneath us. In either case, we
* should just throw away the buffer.
*
* Lockdep complains if this is done under the spinlock, so we
* handle it during the unlock path.
*/
if (!priv->enabled || dbuf->size != priv->bufsize) {
drop_buffer = true;
goto out_unlock;
}
/* The buffer is safe to reuse, so add it back to the free list */
list_add_tail(&dbuf->entry, &priv->free);
out_unlock:
spin_unlock_irq(&priv->lock);
if (drop_buffer) {
videobuf_dma_unmap(priv->dev, &dbuf->vb);
data_free_buffer(dbuf);
}
return count;
}
static unsigned int data_poll(struct file *filp, struct poll_table_struct *tbl)
{
struct fpga_reader *reader = filp->private_data;
struct fpga_device *priv = reader->priv;
unsigned int mask = 0;
poll_wait(filp, &priv->wait, tbl);
if (!list_empty(&priv->used))
mask |= POLLIN | POLLRDNORM;
return mask;
}
static int data_mmap(struct file *filp, struct vm_area_struct *vma)
{
struct fpga_reader *reader = filp->private_data;
struct fpga_device *priv = reader->priv;
unsigned long offset, vsize, psize, addr;
/* VMA properties */
offset = vma->vm_pgoff << PAGE_SHIFT;
vsize = vma->vm_end - vma->vm_start;
psize = priv->phys_size - offset;
addr = (priv->phys_addr + offset) >> PAGE_SHIFT;
/* Check against the FPGA region's physical memory size */
if (vsize > psize) {
dev_err(priv->dev, "requested mmap mapping too large\n");
return -EINVAL;
}
vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
return io_remap_pfn_range(vma, vma->vm_start, addr, vsize,
vma->vm_page_prot);
}
static const struct file_operations data_fops = {
.owner = THIS_MODULE,
.open = data_open,
.release = data_release,
.read = data_read,
.poll = data_poll,
.mmap = data_mmap,
.llseek = no_llseek,
};
/*
* OpenFirmware Device Subsystem
*/
static bool dma_filter(struct dma_chan *chan, void *data)
{
/*
* DMA Channel #0 is used for the FPGA Programmer, so ignore it
*
* This probably won't survive an unload/load cycle of the Freescale
* DMAEngine driver, but that won't be a problem
*/
if (chan->chan_id == 0 && chan->device->dev_id == 0)
return false;
return true;
}
static int data_of_probe(struct platform_device *op)
{
struct device_node *of_node = op->dev.of_node;
struct device *this_device;
struct fpga_device *priv;
struct resource res;
dma_cap_mask_t mask;
int ret;
/* Allocate private data */
priv = kzalloc(sizeof(*priv), GFP_KERNEL);
if (!priv) {
dev_err(&op->dev, "Unable to allocate device private data\n");
ret = -ENOMEM;
goto out_return;
}
dev_set_drvdata(&op->dev, priv);
priv->dev = &op->dev;
kref_init(&priv->ref);
mutex_init(&priv->mutex);
dev_set_drvdata(priv->dev, priv);
spin_lock_init(&priv->lock);
INIT_LIST_HEAD(&priv->free);
INIT_LIST_HEAD(&priv->used);
init_waitqueue_head(&priv->wait);
/* Setup the misc device */
priv->miscdev.minor = MISC_DYNAMIC_MINOR;
priv->miscdev.name = drv_name;
priv->miscdev.fops = &data_fops;
/* Get the physical address of the FPGA registers */
ret = of_address_to_resource(of_node, 0, &res);
if (ret) {
dev_err(&op->dev, "Unable to find FPGA physical address\n");
ret = -ENODEV;
goto out_free_priv;
}
priv->phys_addr = res.start;
priv->phys_size = resource_size(&res);
/* ioremap the registers for use */
priv->regs = of_iomap(of_node, 0);
if (!priv->regs) {
dev_err(&op->dev, "Unable to ioremap registers\n");
ret = -ENOMEM;
goto out_free_priv;
}
dma_cap_zero(mask);
dma_cap_set(DMA_MEMCPY, mask);
dma_cap_set(DMA_INTERRUPT, mask);
dma_cap_set(DMA_SLAVE, mask);
dma_cap_set(DMA_SG, mask);
/* Request a DMA channel */
priv->chan = dma_request_channel(mask, dma_filter, NULL);
if (!priv->chan) {
dev_err(&op->dev, "Unable to request DMA channel\n");
ret = -ENODEV;
goto out_unmap_regs;
}
/* Find the correct IRQ number */
priv->irq = irq_of_parse_and_map(of_node, 0);
if (priv->irq == NO_IRQ) {
dev_err(&op->dev, "Unable to find IRQ line\n");
ret = -ENODEV;
goto out_release_dma;
}
/* Drive the GPIO for FPGA IRQ high (no interrupt) */
iowrite32be(IRQ_CORL_DONE, priv->regs + SYS_IRQ_OUTPUT_DATA);
/* Register the miscdevice */
ret = misc_register(&priv->miscdev);
if (ret) {
dev_err(&op->dev, "Unable to register miscdevice\n");
goto out_irq_dispose_mapping;
}
/* Create the debugfs files */
ret = data_debugfs_init(priv);
if (ret) {
dev_err(&op->dev, "Unable to create debugfs files\n");
goto out_misc_deregister;
}
/* Create the sysfs files */
this_device = priv->miscdev.this_device;
dev_set_drvdata(this_device, priv);
ret = sysfs_create_group(&this_device->kobj, &rt_sysfs_attr_group);
if (ret) {
dev_err(&op->dev, "Unable to create sysfs files\n");
goto out_data_debugfs_exit;
}
dev_info(&op->dev, "CARMA FPGA Realtime Data Driver Loaded\n");
return 0;
out_data_debugfs_exit:
data_debugfs_exit(priv);
out_misc_deregister:
misc_deregister(&priv->miscdev);
out_irq_dispose_mapping:
irq_dispose_mapping(priv->irq);
out_release_dma:
dma_release_channel(priv->chan);
out_unmap_regs:
iounmap(priv->regs);
out_free_priv:
kref_put(&priv->ref, fpga_device_release);
out_return:
return ret;
}
static int data_of_remove(struct platform_device *op)
{
struct fpga_device *priv = dev_get_drvdata(&op->dev);
struct device *this_device = priv->miscdev.this_device;
/* remove all sysfs files, now the device cannot be re-enabled */
sysfs_remove_group(&this_device->kobj, &rt_sysfs_attr_group);
/* remove all debugfs files */
data_debugfs_exit(priv);
/* disable the device from generating data */
data_device_disable(priv);
/* remove the character device to stop new readers from appearing */
misc_deregister(&priv->miscdev);
/* cleanup everything not needed by readers */
irq_dispose_mapping(priv->irq);
dma_release_channel(priv->chan);
iounmap(priv->regs);
/* release our reference */
kref_put(&priv->ref, fpga_device_release);
return 0;
}
static struct of_device_id data_of_match[] = {
{ .compatible = "carma,carma-fpga", },
{},
};
static struct platform_driver data_of_driver = {
.probe = data_of_probe,
.remove = data_of_remove,
.driver = {
.name = drv_name,
.of_match_table = data_of_match,
.owner = THIS_MODULE,
},
};
module_platform_driver(data_of_driver);
MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>");
MODULE_DESCRIPTION("CARMA DATA-FPGA Access Driver");
MODULE_LICENSE("GPL");