1 files changed, 415 insertions, 0 deletions
diff --git a/drivers/media/pci/tw686x/tw686x-core.c b/drivers/media/pci/tw686x/tw686x-core.c
new file mode 100644
index 000000000000..cf53b0e97be2
--- /dev/null
+++ b/drivers/media/pci/tw686x/tw686x-core.c
@@ -0,0 +1,415 @@
+/*
+ * 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
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2 of the GNU General Public License
+ * as published by the Free Software Foundation.
+ *
+ * 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.
+ * This driver tries to access hardware registers as infrequently
+ * as possible by:
+ *   i.  allocating fixed DMA buffers and memcpy'ing into
+ *       vmalloc'ed buffers
+ *   ii. using a timer to mitigate the rate of DMA reset operations,
+ *       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");
+
+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(unsigned long data)
+{
+	struct tw686x_dev *dev = (struct tw686x_dev *)data;
+	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;
+	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\n", dev->name,
+		pci_name(pci_dev), pci_dev->irq,
+		(unsigned long)pci_resource_start(pci_dev, 0));
+
+	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;
+	}
+
+	setup_timer(&dev->dma_delay_timer,
+		    tw686x_dma_delay, (unsigned long) dev);
+
+	/*
+	 * 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");