--- /dev/null
+/*
+ * 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);
+
+ /* 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;
+
+ /* clear the FPGA status and re-enable interrupts */
+ 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;
+
+ 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_PREP_INTERRUPT);
+ 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);
+
+ /* 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_memcpy_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)
+{
+ u32 val;
+ int ret;
+
+ /* multiple enables are safe: they do nothing */
+ if (priv->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;
+ }
+
+ /* 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;
+ }
+
+ /* switch to the external FPGA IRQ line */
+ data_enable_interrupts(priv);
+
+ /* success, we're enabled */
+ priv->enabled = true;
+ 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)
+{
+ int ret;
+
+ /* allow multiple disable */
+ if (!priv->enabled)
+ return 0;
+
+ /* switch to the internal GPIO IRQ line */
+ data_disable_interrupts(priv);
+
+ /* unhook the irq handler */
+ free_irq(priv->irq, priv);
+
+ /*
+ * wait for all outstanding DMA to complete
+ *
+ * Device interrupts are disabled, therefore another buffer cannot
+ * be marked inflight.
+ */
+ ret = wait_event_interruptible(priv->wait, priv->inflight == NULL);
+ if (ret)
+ return ret;
+
+ /* free the correlation table */
+ sg_free_table(&priv->corl_table);
+ priv->corl_nents = 0;
+
+ /*
+ * We are taking the spinlock not to protect priv->enabled, but instead
+ * to make sure that there are no readers in the process of altering
+ * the free or used lists while we are setting this flag.
+ */
+ spin_lock_irq(&priv->lock);
+ priv->enabled = false;
+ spin_unlock_irq(&priv->lock);
+
+ /* 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;
+ int ret;
+
+ /*
+ * Lock the mutex first, so that we get an accurate value for enable
+ * Lock the spinlock next, to get accurate list counts
+ */
+ ret = mutex_lock_interruptible(&priv->mutex);
+ if (ret)
+ return ret;
+
+ 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);
+ mutex_unlock(&priv->mutex);
+ 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);
+ return snprintf(buf, PAGE_SIZE, "%u\n", priv->enabled);
+}
+
+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;
+ }
+
+ 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;
+ 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.
+ */
+ if (!priv->enabled || dbuf->size != priv->bufsize) {
+ videobuf_dma_unmap(priv->dev, &dbuf->vb);
+ data_free_buffer(dbuf);
+ 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);
+ 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;
+ }
+
+ /* IO memory (stop cacheing) */
+ vma->vm_flags |= VM_IO | VM_RESERVED;
+ 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,
+ const struct of_device_id *match)
+{
+ 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 of_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 Init / Exit
+ */
+
+static int __init data_init(void)
+{
+ return of_register_platform_driver(&data_of_driver);
+}
+
+static void __exit data_exit(void)
+{
+ of_unregister_platform_driver(&data_of_driver);
+}
+
+MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>");
+MODULE_DESCRIPTION("CARMA DATA-FPGA Access Driver");
+MODULE_LICENSE("GPL");
+
+module_init(data_init);
+module_exit(data_exit);
git.openpandora.org / pandora-kernel.git / blobdiff