WSL2-Linux-Kernel/drivers/media/pci/tw686x/tw686x-core.c

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C
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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2015 VanguardiaSur - www.vanguardiasur.com.ar
*
* Based on original driver by Krzysztof Ha?asa:
* Copyright (C) 2015 Industrial Research Institute for Automation
* and Measurements PIAP
*
* Notes
* -----
*
* 1. Under stress-testing, it has been observed that the PCIe link
* goes down, without reason. Therefore, the driver takes special care
* to allow device hot-unplugging.
*
* 2. TW686X devices are capable of setting a few different DMA modes,
* including: scatter-gather, field and frame modes. However,
* under stress testings it has been found that the machine can
* freeze completely if DMA registers are programmed while streaming
* is active.
*
* Therefore, driver implements a dma_mode called 'memcpy' which
* avoids cycling the DMA buffers, and insteads allocates extra DMA buffers
* and then copies into vmalloc'ed user buffers.
*
* In addition to this, when streaming is on, the driver tries to access
* hardware registers as infrequently as possible. This is done by using
* a timer to limit the rate at which DMA is reset on DMA channels error.
*/
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci_ids.h>
#include <linux/slab.h>
#include <linux/timer.h>
#include "tw686x.h"
#include "tw686x-regs.h"
/*
* This module parameter allows to control the DMA_TIMER_INTERVAL value.
* The DMA_TIMER_INTERVAL register controls the minimum DMA interrupt
* time span (iow, the maximum DMA interrupt rate) thus allowing for
* IRQ coalescing.
*
* The chip datasheet does not mention a time unit for this value, so
* users wanting fine-grain control over the interrupt rate should
* determine the desired value through testing.
*/
static u32 dma_interval = 0x00098968;
module_param(dma_interval, int, 0444);
MODULE_PARM_DESC(dma_interval, "Minimum time span for DMA interrupting host");
static unsigned int dma_mode = TW686X_DMA_MODE_MEMCPY;
static const char *dma_mode_name(unsigned int mode)
{
switch (mode) {
case TW686X_DMA_MODE_MEMCPY:
return "memcpy";
case TW686X_DMA_MODE_CONTIG:
return "contig";
case TW686X_DMA_MODE_SG:
return "sg";
default:
return "unknown";
}
}
static int tw686x_dma_mode_get(char *buffer, const struct kernel_param *kp)
{
return sprintf(buffer, "%s", dma_mode_name(dma_mode));
}
static int tw686x_dma_mode_set(const char *val, const struct kernel_param *kp)
{
if (!strcasecmp(val, dma_mode_name(TW686X_DMA_MODE_MEMCPY)))
dma_mode = TW686X_DMA_MODE_MEMCPY;
else if (!strcasecmp(val, dma_mode_name(TW686X_DMA_MODE_CONTIG)))
dma_mode = TW686X_DMA_MODE_CONTIG;
else if (!strcasecmp(val, dma_mode_name(TW686X_DMA_MODE_SG)))
dma_mode = TW686X_DMA_MODE_SG;
else
return -EINVAL;
return 0;
}
module_param_call(dma_mode, tw686x_dma_mode_set, tw686x_dma_mode_get,
&dma_mode, S_IRUGO|S_IWUSR);
MODULE_PARM_DESC(dma_mode, "DMA operation mode (memcpy/contig/sg, default=memcpy)");
void tw686x_disable_channel(struct tw686x_dev *dev, unsigned int channel)
{
u32 dma_en = reg_read(dev, DMA_CHANNEL_ENABLE);
u32 dma_cmd = reg_read(dev, DMA_CMD);
dma_en &= ~BIT(channel);
dma_cmd &= ~BIT(channel);
/* Must remove it from pending too */
dev->pending_dma_en &= ~BIT(channel);
dev->pending_dma_cmd &= ~BIT(channel);
/* Stop DMA if no channels are enabled */
if (!dma_en)
dma_cmd = 0;
reg_write(dev, DMA_CHANNEL_ENABLE, dma_en);
reg_write(dev, DMA_CMD, dma_cmd);
}
void tw686x_enable_channel(struct tw686x_dev *dev, unsigned int channel)
{
u32 dma_en = reg_read(dev, DMA_CHANNEL_ENABLE);
u32 dma_cmd = reg_read(dev, DMA_CMD);
dev->pending_dma_en |= dma_en | BIT(channel);
dev->pending_dma_cmd |= dma_cmd | DMA_CMD_ENABLE | BIT(channel);
}
/*
* The purpose of this awful hack is to avoid enabling the DMA
* channels "too fast" which makes some TW686x devices very
* angry and freeze the CPU (see note 1).
*/
static void tw686x_dma_delay(struct timer_list *t)
{
struct tw686x_dev *dev = from_timer(dev, t, dma_delay_timer);
unsigned long flags;
spin_lock_irqsave(&dev->lock, flags);
reg_write(dev, DMA_CHANNEL_ENABLE, dev->pending_dma_en);
reg_write(dev, DMA_CMD, dev->pending_dma_cmd);
dev->pending_dma_en = 0;
dev->pending_dma_cmd = 0;
spin_unlock_irqrestore(&dev->lock, flags);
}
static void tw686x_reset_channels(struct tw686x_dev *dev, unsigned int ch_mask)
{
u32 dma_en, dma_cmd;
dma_en = reg_read(dev, DMA_CHANNEL_ENABLE);
dma_cmd = reg_read(dev, DMA_CMD);
/*
* Save pending register status, the timer will
* restore them.
*/
dev->pending_dma_en |= dma_en;
dev->pending_dma_cmd |= dma_cmd;
/* Disable the reset channels */
reg_write(dev, DMA_CHANNEL_ENABLE, dma_en & ~ch_mask);
if ((dma_en & ~ch_mask) == 0) {
dev_dbg(&dev->pci_dev->dev, "reset: stopping DMA\n");
dma_cmd &= ~DMA_CMD_ENABLE;
}
reg_write(dev, DMA_CMD, dma_cmd & ~ch_mask);
}
static irqreturn_t tw686x_irq(int irq, void *dev_id)
{
struct tw686x_dev *dev = (struct tw686x_dev *)dev_id;
unsigned int video_requests, audio_requests, reset_ch;
u32 fifo_status, fifo_signal, fifo_ov, fifo_bad, fifo_errors;
u32 int_status, dma_en, video_en, pb_status;
unsigned long flags;
int_status = reg_read(dev, INT_STATUS); /* cleared on read */
fifo_status = reg_read(dev, VIDEO_FIFO_STATUS);
/* INT_STATUS does not include FIFO_STATUS errors! */
if (!int_status && !TW686X_FIFO_ERROR(fifo_status))
return IRQ_NONE;
if (int_status & INT_STATUS_DMA_TOUT) {
dev_dbg(&dev->pci_dev->dev,
"DMA timeout. Resetting DMA for all channels\n");
reset_ch = ~0;
goto reset_channels;
}
spin_lock_irqsave(&dev->lock, flags);
dma_en = reg_read(dev, DMA_CHANNEL_ENABLE);
spin_unlock_irqrestore(&dev->lock, flags);
video_en = dma_en & 0xff;
fifo_signal = ~(fifo_status & 0xff) & video_en;
fifo_ov = fifo_status >> 24;
fifo_bad = fifo_status >> 16;
/* Mask of channels with signal and FIFO errors */
fifo_errors = fifo_signal & (fifo_ov | fifo_bad);
reset_ch = 0;
pb_status = reg_read(dev, PB_STATUS);
/* Coalesce video frame/error events */
video_requests = (int_status & video_en) | fifo_errors;
audio_requests = (int_status & dma_en) >> 8;
if (video_requests)
tw686x_video_irq(dev, video_requests, pb_status,
fifo_status, &reset_ch);
if (audio_requests)
tw686x_audio_irq(dev, audio_requests, pb_status);
reset_channels:
if (reset_ch) {
spin_lock_irqsave(&dev->lock, flags);
tw686x_reset_channels(dev, reset_ch);
spin_unlock_irqrestore(&dev->lock, flags);
mod_timer(&dev->dma_delay_timer,
jiffies + msecs_to_jiffies(100));
}
return IRQ_HANDLED;
}
static void tw686x_dev_release(struct v4l2_device *v4l2_dev)
{
struct tw686x_dev *dev = container_of(v4l2_dev, struct tw686x_dev,
v4l2_dev);
unsigned int ch;
for (ch = 0; ch < max_channels(dev); ch++)
v4l2_ctrl_handler_free(&dev->video_channels[ch].ctrl_handler);
v4l2_device_unregister(&dev->v4l2_dev);
kfree(dev->audio_channels);
kfree(dev->video_channels);
kfree(dev);
}
static int tw686x_probe(struct pci_dev *pci_dev,
const struct pci_device_id *pci_id)
{
struct tw686x_dev *dev;
int err;
dev = kzalloc(sizeof(*dev), GFP_KERNEL);
if (!dev)
return -ENOMEM;
dev->type = pci_id->driver_data;
dev->dma_mode = dma_mode;
sprintf(dev->name, "tw%04X", pci_dev->device);
dev->video_channels = kcalloc(max_channels(dev),
sizeof(*dev->video_channels), GFP_KERNEL);
if (!dev->video_channels) {
err = -ENOMEM;
goto free_dev;
}
dev->audio_channels = kcalloc(max_channels(dev),
sizeof(*dev->audio_channels), GFP_KERNEL);
if (!dev->audio_channels) {
err = -ENOMEM;
goto free_video;
}
pr_info("%s: PCI %s, IRQ %d, MMIO 0x%lx (%s mode)\n", dev->name,
pci_name(pci_dev), pci_dev->irq,
(unsigned long)pci_resource_start(pci_dev, 0),
dma_mode_name(dma_mode));
dev->pci_dev = pci_dev;
if (pci_enable_device(pci_dev)) {
err = -EIO;
goto free_audio;
}
pci_set_master(pci_dev);
err = pci_set_dma_mask(pci_dev, DMA_BIT_MASK(32));
if (err) {
dev_err(&pci_dev->dev, "32-bit PCI DMA not supported\n");
err = -EIO;
goto disable_pci;
}
err = pci_request_regions(pci_dev, dev->name);
if (err) {
dev_err(&pci_dev->dev, "unable to request PCI region\n");
goto disable_pci;
}
dev->mmio = pci_ioremap_bar(pci_dev, 0);
if (!dev->mmio) {
dev_err(&pci_dev->dev, "unable to remap PCI region\n");
err = -ENOMEM;
goto free_region;
}
/* Reset all subsystems */
reg_write(dev, SYS_SOFT_RST, 0x0f);
mdelay(1);
reg_write(dev, SRST[0], 0x3f);
if (max_channels(dev) > 4)
reg_write(dev, SRST[1], 0x3f);
/* Disable the DMA engine */
reg_write(dev, DMA_CMD, 0);
reg_write(dev, DMA_CHANNEL_ENABLE, 0);
/* Enable DMA FIFO overflow and pointer check */
reg_write(dev, DMA_CONFIG, 0xffffff04);
reg_write(dev, DMA_CHANNEL_TIMEOUT, 0x140c8584);
reg_write(dev, DMA_TIMER_INTERVAL, dma_interval);
spin_lock_init(&dev->lock);
err = request_irq(pci_dev->irq, tw686x_irq, IRQF_SHARED,
dev->name, dev);
if (err < 0) {
dev_err(&pci_dev->dev, "unable to request interrupt\n");
goto iounmap;
}
timer_setup(&dev->dma_delay_timer, tw686x_dma_delay, 0);
/*
* This must be set right before initializing v4l2_dev.
* It's used to release resources after the last handle
* held is released.
*/
dev->v4l2_dev.release = tw686x_dev_release;
err = tw686x_video_init(dev);
if (err) {
dev_err(&pci_dev->dev, "can't register video\n");
goto free_irq;
}
err = tw686x_audio_init(dev);
if (err)
dev_warn(&pci_dev->dev, "can't register audio\n");
pci_set_drvdata(pci_dev, dev);
return 0;
free_irq:
free_irq(pci_dev->irq, dev);
iounmap:
pci_iounmap(pci_dev, dev->mmio);
free_region:
pci_release_regions(pci_dev);
disable_pci:
pci_disable_device(pci_dev);
free_audio:
kfree(dev->audio_channels);
free_video:
kfree(dev->video_channels);
free_dev:
kfree(dev);
return err;
}
static void tw686x_remove(struct pci_dev *pci_dev)
{
struct tw686x_dev *dev = pci_get_drvdata(pci_dev);
unsigned long flags;
/* This guarantees the IRQ handler is no longer running,
* which means we can kiss good-bye some resources.
*/
free_irq(pci_dev->irq, dev);
tw686x_video_free(dev);
tw686x_audio_free(dev);
del_timer_sync(&dev->dma_delay_timer);
pci_iounmap(pci_dev, dev->mmio);
pci_release_regions(pci_dev);
pci_disable_device(pci_dev);
/*
* Setting pci_dev to NULL allows to detect hardware is no longer
* available and will be used by vb2_ops. This is required because
* the device sometimes hot-unplugs itself as the result of a PCIe
* link down.
* The lock is really important here.
*/
spin_lock_irqsave(&dev->lock, flags);
dev->pci_dev = NULL;
spin_unlock_irqrestore(&dev->lock, flags);
/*
* This calls tw686x_dev_release if it's the last reference.
* Otherwise, release is postponed until there are no users left.
*/
v4l2_device_put(&dev->v4l2_dev);
}
/*
* On TW6864 and TW6868, all channels share the pair of video DMA SG tables,
* with 10-bit start_idx and end_idx determining start and end of frame buffer
* for particular channel.
* TW6868 with all its 8 channels would be problematic (only 127 SG entries per
* channel) but we support only 4 channels on this chip anyway (the first
* 4 channels are driven with internal video decoder, the other 4 would require
* an external TW286x part).
*
* On TW6865 and TW6869, each channel has its own DMA SG table, with indexes
* starting with 0. Both chips have complete sets of internal video decoders
* (respectively 4 or 8-channel).
*
* All chips have separate SG tables for two video frames.
*/
/* driver_data is number of A/V channels */
static const struct pci_device_id tw686x_pci_tbl[] = {
{
PCI_DEVICE(PCI_VENDOR_ID_TECHWELL, 0x6864),
.driver_data = 4
},
{
PCI_DEVICE(PCI_VENDOR_ID_TECHWELL, 0x6865), /* not tested */
.driver_data = 4 | TYPE_SECOND_GEN
},
/*
* TW6868 supports 8 A/V channels with an external TW2865 chip;
* not supported by the driver.
*/
{
PCI_DEVICE(PCI_VENDOR_ID_TECHWELL, 0x6868), /* not tested */
.driver_data = 4
},
{
PCI_DEVICE(PCI_VENDOR_ID_TECHWELL, 0x6869),
.driver_data = 8 | TYPE_SECOND_GEN},
{}
};
MODULE_DEVICE_TABLE(pci, tw686x_pci_tbl);
static struct pci_driver tw686x_pci_driver = {
.name = "tw686x",
.id_table = tw686x_pci_tbl,
.probe = tw686x_probe,
.remove = tw686x_remove,
};
module_pci_driver(tw686x_pci_driver);
MODULE_DESCRIPTION("Driver for video frame grabber cards based on Intersil/Techwell TW686[4589]");
MODULE_AUTHOR("Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>");
MODULE_AUTHOR("Krzysztof Ha?asa <khalasa@piap.pl>");
MODULE_LICENSE("GPL v2");