+++ /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_address.h>
-#include <linux/of_irq.h>
-#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/vmalloc.h>
-#include <linux/kernel.h>
-#include <linux/module.h>
-#include <linux/poll.h>
-#include <linux/slab.h>
-#include <linux/kref.h>
-#include <linux/io.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;
- void *vaddr;
- struct scatterlist *sglist;
- int sglen;
- int nr_pages;
- 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
- */
-
-static int carma_dma_init(struct data_buf *buf, int nr_pages)
-{
- struct page *pg;
- int i;
-
- buf->vaddr = vmalloc_32(nr_pages << PAGE_SHIFT);
- if (NULL == buf->vaddr) {
- pr_debug("vmalloc_32(%d pages) failed\n", nr_pages);
- return -ENOMEM;
- }
-
- pr_debug("vmalloc is at addr 0x%08lx, size=%d\n",
- (unsigned long)buf->vaddr,
- nr_pages << PAGE_SHIFT);
-
- memset(buf->vaddr, 0, nr_pages << PAGE_SHIFT);
- buf->nr_pages = nr_pages;
-
- buf->sglist = vzalloc(buf->nr_pages * sizeof(*buf->sglist));
- if (NULL == buf->sglist)
- goto vzalloc_err;
-
- sg_init_table(buf->sglist, buf->nr_pages);
- for (i = 0; i < buf->nr_pages; i++) {
- pg = vmalloc_to_page(buf->vaddr + i * PAGE_SIZE);
- if (NULL == pg)
- goto vmalloc_to_page_err;
- sg_set_page(&buf->sglist[i], pg, PAGE_SIZE, 0);
- }
- return 0;
-
-vmalloc_to_page_err:
- vfree(buf->sglist);
- buf->sglist = NULL;
-vzalloc_err:
- vfree(buf->vaddr);
- buf->vaddr = NULL;
- return -ENOMEM;
-}
-
-static int carma_dma_map(struct device *dev, struct data_buf *buf)
-{
- buf->sglen = dma_map_sg(dev, buf->sglist,
- buf->nr_pages, DMA_FROM_DEVICE);
-
- if (0 == buf->sglen) {
- pr_warn("%s: dma_map_sg failed\n", __func__);
- return -ENOMEM;
- }
- return 0;
-}
-
-static int carma_dma_unmap(struct device *dev, struct data_buf *buf)
-{
- if (!buf->sglen)
- return 0;
-
- dma_unmap_sg(dev, buf->sglist, buf->sglen, DMA_FROM_DEVICE);
- buf->sglen = 0;
- return 0;
-}
-
-/**
- * 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 */
- vfree(buf->sglist);
- vfree(buf->vaddr);
- 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 carma_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 buffer */
- ret = carma_dma_init(buf, 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);
- carma_dma_unmap(priv->dev, buf);
- data_free_buffer(buf);
- }
-
- list_for_each_entry_safe(buf, tmp, &priv->used, entry) {
- list_del_init(&buf->entry);
- carma_dma_unmap(priv->dev, buf);
- 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 = carma_dma_map(priv->dev, buf);
- 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 = 0;
-
- dst_sg = buf->sglist;
- dst_nents = buf->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);
- return PTR_ERR_OR_ZERO(priv->dbg_entry);
-}
-
-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 = kstrtoul(buf, 0, &enable);
- if (ret) {
- dev_err(priv->dev, "unable to parse enable input\n");
- return ret;
- }
-
- /* 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 */
- carma_dma_unmap(priv->dev, dbuf);
-
- /* 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->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 = carma_dma_map(priv->dev, dbuf);
- 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) {
- carma_dma_unmap(priv->dev, dbuf);
- 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;
- }
-
- platform_set_drvdata(op, 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 = platform_get_drvdata(op);
- 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 const 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,
- },
-};
-
-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");
Code Review / kvmfornfv.git / blobdiff