drm/i915: setup bridge for HDMI LPE audio driver

Enable support for HDMI LPE audio mode on Baytrail and
Cherrytrail when HDaudio controller is not detected

Setup minimum required resources during i915_driver_load:
1. Create a platform device to share MMIO/IRQ resources
2. Make the platform device child of i915 device for runtime PM.
3. Create IRQ chip to forward HDMI LPE audio irqs.

HDMI LPE audio driver (a standalone sound driver) probes the
LPE audio device and creates a new sound card.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Jerome Anand <jerome.anand@intel.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 321 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_lpe_audio.c b/drivers/gpu/drm/i915/intel_lpe_audio.c
new file mode 100644
index 000000000000..7ce1b5b99275
--- /dev/null
+++ b/drivers/gpu/drm/i915/intel_lpe_audio.c
@@ -0,0 +1,321 @@
+/*
+ * Copyright © 2016 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ * Authors:
+ *    Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
+ *    Jerome Anand <jerome.anand@intel.com>
+ *    based on VED patches
+ *
+ */
+
+/**
+ * DOC: LPE Audio integration for HDMI or DP playback
+ *
+ * Motivation:
+ * Atom platforms (e.g. valleyview and cherryTrail) integrates a DMA-based
+ * interface as an alternative to the traditional HDaudio path. While this
+ * mode is unrelated to the LPE aka SST audio engine, the documentation refers
+ * to this mode as LPE so we keep this notation for the sake of consistency.
+ *
+ * The interface is handled by a separate standalone driver maintained in the
+ * ALSA subsystem for simplicity. To minimize the interaction between the two
+ * subsystems, a bridge is setup between the hdmi-lpe-audio and i915:
+ * 1. Create a platform device to share MMIO/IRQ resources
+ * 2. Make the platform device child of i915 device for runtime PM.
+ * 3. Create IRQ chip to forward the LPE audio irqs.
+ * the hdmi-lpe-audio driver probes the lpe audio device and creates a new
+ * sound card
+ *
+ * Threats:
+ * Due to the restriction in Linux platform device model, user need manually
+ * uninstall the hdmi-lpe-audio driver before uninstalling i915 module,
+ * otherwise we might run into use-after-free issues after i915 removes the
+ * platform device: even though hdmi-lpe-audio driver is released, the modules
+ * is still in "installed" status.
+ *
+ * Implementation:
+ * The MMIO/REG platform resources are created according to the registers
+ * specification.
+ * When forwarding LPE audio irqs, the flow control handler selection depends
+ * on the platform, for example on valleyview handle_simple_irq is enough.
+ *
+ */
+
+#include <linux/acpi.h>
+#include <linux/device.h>
+#include <linux/pci.h>
+
+#include "i915_drv.h"
+#include <linux/delay.h>
+#include <drm/intel_lpe_audio.h>
+
+#define HAS_LPE_AUDIO(dev_priv) ((dev_priv)->lpe_audio.platdev != NULL)
+
+static struct platform_device *
+lpe_audio_platdev_create(struct drm_i915_private *dev_priv)
+{
+	int ret;
+	struct drm_device *dev = &dev_priv->drm;
+	struct platform_device_info pinfo = {};
+	struct resource *rsc;
+	struct platform_device *platdev;
+	struct intel_hdmi_lpe_audio_pdata *pdata;
+
+	pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
+	if (!pdata)
+		return ERR_PTR(-ENOMEM);
+
+	rsc = kcalloc(2, sizeof(*rsc), GFP_KERNEL);
+	if (!rsc) {
+		kfree(pdata);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	rsc[0].start    = rsc[0].end = dev_priv->lpe_audio.irq;
+	rsc[0].flags    = IORESOURCE_IRQ;
+	rsc[0].name     = "hdmi-lpe-audio-irq";
+
+	rsc[1].start    = pci_resource_start(dev->pdev, 0) +
+		I915_HDMI_LPE_AUDIO_BASE;
+	rsc[1].end      = pci_resource_start(dev->pdev, 0) +
+		I915_HDMI_LPE_AUDIO_BASE + I915_HDMI_LPE_AUDIO_SIZE - 1;
+	rsc[1].flags    = IORESOURCE_MEM;
+	rsc[1].name     = "hdmi-lpe-audio-mmio";
+
+	pinfo.parent = dev->dev;
+	pinfo.name = "hdmi-lpe-audio";
+	pinfo.id = -1;
+	pinfo.res = rsc;
+	pinfo.num_res = 2;
+	pinfo.data = pdata;
+	pinfo.size_data = sizeof(*pdata);
+	pinfo.dma_mask = DMA_BIT_MASK(32);
+
+	spin_lock_init(&pdata->lpe_audio_slock);
+
+	platdev = platform_device_register_full(&pinfo);
+	if (IS_ERR(platdev)) {
+		ret = PTR_ERR(platdev);
+		DRM_ERROR("Failed to allocate LPE audio platform device\n");
+		goto err;
+	}
+
+	kfree(rsc);
+
+	return platdev;
+
+err:
+	kfree(rsc);
+	kfree(pdata);
+	return ERR_PTR(ret);
+}
+
+static void lpe_audio_platdev_destroy(struct drm_i915_private *dev_priv)
+{
+	platform_device_unregister(dev_priv->lpe_audio.platdev);
+	kfree(dev_priv->lpe_audio.platdev->dev.dma_mask);
+}
+
+static void lpe_audio_irq_unmask(struct irq_data *d)
+{
+	struct drm_i915_private *dev_priv = d->chip_data;
+	unsigned long irqflags;
+	u32 val = (I915_LPE_PIPE_A_INTERRUPT |
+		I915_LPE_PIPE_B_INTERRUPT);
+
+	if (IS_CHERRYVIEW(dev_priv))
+		val |= I915_LPE_PIPE_C_INTERRUPT;
+
+	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
+
+	dev_priv->irq_mask &= ~val;
+	I915_WRITE(VLV_IIR, val);
+	I915_WRITE(VLV_IIR, val);
+	I915_WRITE(VLV_IMR, dev_priv->irq_mask);
+	POSTING_READ(VLV_IMR);
+
+	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
+}
+
+static void lpe_audio_irq_mask(struct irq_data *d)
+{
+	struct drm_i915_private *dev_priv = d->chip_data;
+	unsigned long irqflags;
+	u32 val = (I915_LPE_PIPE_A_INTERRUPT |
+		I915_LPE_PIPE_B_INTERRUPT);
+
+	if (IS_CHERRYVIEW(dev_priv))
+		val |= I915_LPE_PIPE_C_INTERRUPT;
+
+	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
+
+	dev_priv->irq_mask |= val;
+	I915_WRITE(VLV_IMR, dev_priv->irq_mask);
+	I915_WRITE(VLV_IIR, val);
+	I915_WRITE(VLV_IIR, val);
+	POSTING_READ(VLV_IIR);
+
+	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
+}
+
+static struct irq_chip lpe_audio_irqchip = {
+	.name = "hdmi_lpe_audio_irqchip",
+	.irq_mask = lpe_audio_irq_mask,
+	.irq_unmask = lpe_audio_irq_unmask,
+};
+
+static int lpe_audio_irq_init(struct drm_i915_private *dev_priv)
+{
+	int irq = dev_priv->lpe_audio.irq;
+
+	WARN_ON(!intel_irqs_enabled(dev_priv));
+	irq_set_chip_and_handler_name(irq,
+				&lpe_audio_irqchip,
+				handle_simple_irq,
+				"hdmi_lpe_audio_irq_handler");
+
+	return irq_set_chip_data(irq, dev_priv);
+}
+
+static bool lpe_audio_detect(struct drm_i915_private *dev_priv)
+{
+	int lpe_present = false;
+
+	if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv)) {
+		static const struct pci_device_id atom_hdaudio_ids[] = {
+			/* Baytrail */
+			{PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x0f04)},
+			/* Braswell */
+			{PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x2284)},
+			{}
+		};
+
+		if (!pci_dev_present(atom_hdaudio_ids)) {
+			DRM_INFO("%s\n", "HDaudio controller not detected, using LPE audio instead\n");
+			lpe_present = true;
+		}
+	}
+	return lpe_present;
+}
+
+static int lpe_audio_setup(struct drm_i915_private *dev_priv)
+{
+	int ret;
+
+	dev_priv->lpe_audio.irq = irq_alloc_desc(0);
+	if (dev_priv->lpe_audio.irq < 0) {
+		DRM_ERROR("Failed to allocate IRQ desc: %d\n",
+			dev_priv->lpe_audio.irq);
+		ret = dev_priv->lpe_audio.irq;
+		goto err;
+	}
+
+	DRM_DEBUG("irq = %d\n", dev_priv->lpe_audio.irq);
+
+	ret = lpe_audio_irq_init(dev_priv);
+
+	if (ret) {
+		DRM_ERROR("Failed to initialize irqchip for lpe audio: %d\n",
+			ret);
+		goto err_free_irq;
+	}
+
+	dev_priv->lpe_audio.platdev = lpe_audio_platdev_create(dev_priv);
+
+	if (IS_ERR(dev_priv->lpe_audio.platdev)) {
+		ret = PTR_ERR(dev_priv->lpe_audio.platdev);
+		DRM_ERROR("Failed to create lpe audio platform device: %d\n",
+			ret);
+		goto err_free_irq;
+	}
+
+	return 0;
+err_free_irq:
+	irq_free_desc(dev_priv->lpe_audio.irq);
+err:
+	dev_priv->lpe_audio.irq = -1;
+	dev_priv->lpe_audio.platdev = NULL;
+	return ret;
+}
+
+/**
+ * intel_lpe_audio_irq_handler() - forwards the LPE audio irq
+ * @dev_priv: the i915 drm device private data
+ *
+ * the LPE Audio irq is forwarded to the irq handler registered by LPE audio
+ * driver.
+ */
+void intel_lpe_audio_irq_handler(struct drm_i915_private *dev_priv)
+{
+	int ret;
+
+	if (!HAS_LPE_AUDIO(dev_priv))
+		return;
+
+	ret = generic_handle_irq(dev_priv->lpe_audio.irq);
+	if (ret)
+		DRM_ERROR_RATELIMITED("error handling LPE audio irq: %d\n",
+				ret);
+}
+
+/**
+ * intel_lpe_audio_init() - detect and setup the bridge between HDMI LPE Audio
+ * driver and i915
+ * @dev_priv: the i915 drm device private data
+ *
+ * Return: 0 if successful. non-zero if detection or
+ * llocation/initialization fails
+ */
+int intel_lpe_audio_init(struct drm_i915_private *dev_priv)
+{
+	int ret = -ENODEV;
+
+	if (lpe_audio_detect(dev_priv)) {
+		ret = lpe_audio_setup(dev_priv);
+		if (ret < 0)
+			DRM_ERROR("failed to setup LPE Audio bridge\n");
+	}
+	return ret;
+}
+
+/**
+ * intel_lpe_audio_teardown() - destroy the bridge between HDMI LPE
+ * audio driver and i915
+ * @dev_priv: the i915 drm device private data
+ *
+ * release all the resources for LPE audio <-> i915 bridge.
+ */
+void intel_lpe_audio_teardown(struct drm_i915_private *dev_priv)
+{
+	struct irq_desc *desc;
+
+	if (!HAS_LPE_AUDIO(dev_priv))
+		return;
+
+	desc = irq_to_desc(dev_priv->lpe_audio.irq);
+
+	lpe_audio_irq_mask(&desc->irq_data);
+
+	lpe_audio_platdev_destroy(dev_priv);
+
+	irq_free_desc(dev_priv->lpe_audio.irq);
+}