drivers/gpu/drm/i915/intel_csr.c - kernel/msm-4.19 - Gitiles

 /*
  * Copyright © 2014 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.
  *
  */
 #include <linux/firmware.h>
 #include "i915_drv.h"
 #include "i915_reg.h"

 /**
  * DOC: csr support for dmc
  *
  * Display Context Save and Restore (CSR) firmware support added from gen9
  * onwards to drive newly added DMC (Display microcontroller) in display
  * engine to save and restore the state of display engine when it enter into
  * low-power state and comes back to normal.
  *
  * Firmware loading status will be one of the below states: FW_UNINITIALIZED,
  * FW_LOADED, FW_FAILED.
  *
  * Once the firmware is written into the registers status will be moved from
  * FW_UNINITIALIZED to FW_LOADED and for any erroneous condition status will
  * be moved to FW_FAILED.
  */

 #define I915_CSR_SKL "i915/skl_dmc_ver1.bin"
 #define I915_CSR_BXT "i915/bxt_dmc_ver1.bin"

 #define FIRMWARE_URL  "https://01.org/linuxgraphics/intel-linux-graphics-firmwares"

 MODULE_FIRMWARE(I915_CSR_SKL);
 MODULE_FIRMWARE(I915_CSR_BXT);

 #define SKL_CSR_VERSION_REQUIRED	CSR_VERSION(1, 23)

 #define CSR_MAX_FW_SIZE			0x2FFF
 #define CSR_DEFAULT_FW_OFFSET		0xFFFFFFFF

 struct intel_css_header {
 	/* 0x09 for DMC */
 	uint32_t module_type;

 	/* Includes the DMC specific header in dwords */
 	uint32_t header_len;

 	/* always value would be 0x10000 */
 	uint32_t header_ver;

 	/* Not used */
 	uint32_t module_id;

 	/* Not used */
 	uint32_t module_vendor;

 	/* in YYYYMMDD format */
 	uint32_t date;

 	/* Size in dwords (CSS_Headerlen + PackageHeaderLen + dmc FWsLen)/4 */
 	uint32_t size;

 	/* Not used */
 	uint32_t key_size;

 	/* Not used */
 	uint32_t modulus_size;

 	/* Not used */
 	uint32_t exponent_size;

 	/* Not used */
 	uint32_t reserved1[12];

 	/* Major Minor */
 	uint32_t version;

 	/* Not used */
 	uint32_t reserved2[8];

 	/* Not used */
 	uint32_t kernel_header_info;
 } __packed;

 struct intel_fw_info {
 	uint16_t reserved1;

 	/* Stepping (A, B, C, ..., *). * is a wildcard */
 	char stepping;

 	/* Sub-stepping (0, 1, ..., *). * is a wildcard */
 	char substepping;

 	uint32_t offset;
 	uint32_t reserved2;
 } __packed;

 struct intel_package_header {
 	/* DMC container header length in dwords */
 	unsigned char header_len;

 	/* always value would be 0x01 */
 	unsigned char header_ver;

 	unsigned char reserved[10];

 	/* Number of valid entries in the FWInfo array below */
 	uint32_t num_entries;

 	struct intel_fw_info fw_info[20];
 } __packed;

 struct intel_dmc_header {
 	/* always value would be 0x40403E3E */
 	uint32_t signature;

 	/* DMC binary header length */
 	unsigned char header_len;

 	/* 0x01 */
 	unsigned char header_ver;

 	/* Reserved */
 	uint16_t dmcc_ver;

 	/* Major, Minor */
 	uint32_t	project;

 	/* Firmware program size (excluding header) in dwords */
 	uint32_t	fw_size;

 	/* Major Minor version */
 	uint32_t fw_version;

 	/* Number of valid MMIO cycles present. */
 	uint32_t mmio_count;

 	/* MMIO address */
 	uint32_t mmioaddr[8];

 	/* MMIO data */
 	uint32_t mmiodata[8];

 	/* FW filename  */
 	unsigned char dfile[32];

 	uint32_t reserved1[2];
 } __packed;

 struct stepping_info {
 	char stepping;
 	char substepping;
 };

 /*
  * Kabylake derivated from Skylake H0, so SKL H0
  * is the right firmware for KBL A0 (revid 0).
  */
 static const struct stepping_info kbl_stepping_info[] = {
 	{'H', '0'}, {'I', '0'}
 };

 static const struct stepping_info skl_stepping_info[] = {
 	{'A', '0'}, {'B', '0'}, {'C', '0'},
 	{'D', '0'}, {'E', '0'}, {'F', '0'},
 	{'G', '0'}, {'H', '0'}, {'I', '0'}
 };

 static const struct stepping_info bxt_stepping_info[] = {
 	{'A', '0'}, {'A', '1'}, {'A', '2'},
 	{'B', '0'}, {'B', '1'}, {'B', '2'}
 };

 static const struct stepping_info *intel_get_stepping_info(struct drm_device *dev)
 {
 	const struct stepping_info *si;
 	unsigned int size;

 	if (IS_KABYLAKE(dev)) {
 		size = ARRAY_SIZE(kbl_stepping_info);
 		si = kbl_stepping_info;
 	} else if (IS_SKYLAKE(dev)) {
 		size = ARRAY_SIZE(skl_stepping_info);
 		si = skl_stepping_info;
 	} else if (IS_BROXTON(dev)) {
 		size = ARRAY_SIZE(bxt_stepping_info);
 		si = bxt_stepping_info;
 	} else {
 		return NULL;
 	}

 	if (INTEL_REVID(dev) < size)
 		return si + INTEL_REVID(dev);

 	return NULL;
 }

 /**
  * intel_csr_load_program() - write the firmware from memory to register.
  * @dev_priv: i915 drm device.
  *
  * CSR firmware is read from a .bin file and kept in internal memory one time.
  * Everytime display comes back from low power state this function is called to
  * copy the firmware from internal memory to registers.
  */
 void intel_csr_load_program(struct drm_i915_private *dev_priv)
 {
 	u32 *payload = dev_priv->csr.dmc_payload;
 	uint32_t i, fw_size;

 	if (!IS_GEN9(dev_priv)) {
 		DRM_ERROR("No CSR support available for this platform\n");
 		return;
 	}

 	if (!dev_priv->csr.dmc_payload) {
 		DRM_ERROR("Tried to program CSR with empty payload\n");
 		return;
 	}

 	fw_size = dev_priv->csr.dmc_fw_size;
 	for (i = 0; i < fw_size; i++)
 		I915_WRITE(CSR_PROGRAM(i), payload[i]);

 	for (i = 0; i < dev_priv->csr.mmio_count; i++) {
 		I915_WRITE(dev_priv->csr.mmioaddr[i],
 			   dev_priv->csr.mmiodata[i]);
 	}
 }

 static uint32_t *parse_csr_fw(struct drm_i915_private *dev_priv,
 			      const struct firmware *fw)
 {
 	struct drm_device *dev = dev_priv->dev;
 	struct intel_css_header *css_header;
 	struct intel_package_header *package_header;
 	struct intel_dmc_header *dmc_header;
 	struct intel_csr *csr = &dev_priv->csr;
 	const struct stepping_info *stepping_info = intel_get_stepping_info(dev);
 	char stepping, substepping;
 	uint32_t dmc_offset = CSR_DEFAULT_FW_OFFSET, readcount = 0, nbytes;
 	uint32_t i;
 	uint32_t *dmc_payload;

 	if (!fw)
 		return NULL;

 	if (!stepping_info) {
 		DRM_ERROR("Unknown stepping info, firmware loading failed\n");
 		return NULL;
 	}

 	stepping = stepping_info->stepping;
 	substepping = stepping_info->substepping;

 	/* Extract CSS Header information*/
 	css_header = (struct intel_css_header *)fw->data;
 	if (sizeof(struct intel_css_header) !=
 	    (css_header->header_len * 4)) {
 		DRM_ERROR("Firmware has wrong CSS header length %u bytes\n",
 			  (css_header->header_len * 4));
 		return NULL;
 	}

 	csr->version = css_header->version;

 	if ((IS_SKYLAKE(dev) || IS_KABYLAKE(dev)) &&
 	    csr->version < SKL_CSR_VERSION_REQUIRED) {
 		DRM_INFO("Refusing to load old Skylake DMC firmware v%u.%u,"
 			 " please upgrade to v%u.%u or later"
 			   " [" FIRMWARE_URL "].\n",
 			 CSR_VERSION_MAJOR(csr->version),
 			 CSR_VERSION_MINOR(csr->version),
 			 CSR_VERSION_MAJOR(SKL_CSR_VERSION_REQUIRED),
 			 CSR_VERSION_MINOR(SKL_CSR_VERSION_REQUIRED));
 		return NULL;
 	}

 	readcount += sizeof(struct intel_css_header);

 	/* Extract Package Header information*/
 	package_header = (struct intel_package_header *)
 		&fw->data[readcount];
 	if (sizeof(struct intel_package_header) !=
 	    (package_header->header_len * 4)) {
 		DRM_ERROR("Firmware has wrong package header length %u bytes\n",
 			  (package_header->header_len * 4));
 		return NULL;
 	}
 	readcount += sizeof(struct intel_package_header);

 	/* Search for dmc_offset to find firware binary. */
 	for (i = 0; i < package_header->num_entries; i++) {
 		if (package_header->fw_info[i].substepping == '*' &&
 		    stepping == package_header->fw_info[i].stepping) {
 			dmc_offset = package_header->fw_info[i].offset;
 			break;
 		} else if (stepping == package_header->fw_info[i].stepping &&
 			substepping == package_header->fw_info[i].substepping) {
 			dmc_offset = package_header->fw_info[i].offset;
 			break;
 		} else if (package_header->fw_info[i].stepping == '*' &&
 			   package_header->fw_info[i].substepping == '*')
 			dmc_offset = package_header->fw_info[i].offset;
 	}
 	if (dmc_offset == CSR_DEFAULT_FW_OFFSET) {
 		DRM_ERROR("Firmware not supported for %c stepping\n", stepping);
 		return NULL;
 	}
 	readcount += dmc_offset;

 	/* Extract dmc_header information. */
 	dmc_header = (struct intel_dmc_header *)&fw->data[readcount];
 	if (sizeof(struct intel_dmc_header) != (dmc_header->header_len)) {
 		DRM_ERROR("Firmware has wrong dmc header length %u bytes\n",
 			  (dmc_header->header_len));
 		return NULL;
 	}
 	readcount += sizeof(struct intel_dmc_header);

 	/* Cache the dmc header info. */
 	if (dmc_header->mmio_count > ARRAY_SIZE(csr->mmioaddr)) {
 		DRM_ERROR("Firmware has wrong mmio count %u\n",
 			  dmc_header->mmio_count);
 		return NULL;
 	}
 	csr->mmio_count = dmc_header->mmio_count;
 	for (i = 0; i < dmc_header->mmio_count; i++) {
 		if (dmc_header->mmioaddr[i] < CSR_MMIO_START_RANGE ||
 		    dmc_header->mmioaddr[i] > CSR_MMIO_END_RANGE) {
 			DRM_ERROR(" Firmware has wrong mmio address 0x%x\n",
 				  dmc_header->mmioaddr[i]);
 			return NULL;
 		}
 		csr->mmioaddr[i] = _MMIO(dmc_header->mmioaddr[i]);
 		csr->mmiodata[i] = dmc_header->mmiodata[i];
 	}

 	/* fw_size is in dwords, so multiplied by 4 to convert into bytes. */
 	nbytes = dmc_header->fw_size * 4;
 	if (nbytes > CSR_MAX_FW_SIZE) {
 		DRM_ERROR("CSR firmware too big (%u) bytes\n", nbytes);
 		return NULL;
 	}
 	csr->dmc_fw_size = dmc_header->fw_size;

 	dmc_payload = kmalloc(nbytes, GFP_KERNEL);
 	if (!dmc_payload) {
 		DRM_ERROR("Memory allocation failed for dmc payload\n");
 		return NULL;
 	}

 	memcpy(dmc_payload, &fw->data[readcount], nbytes);

 	return dmc_payload;
 }

 static void csr_load_work_fn(struct work_struct *work)
 {
 	struct drm_i915_private *dev_priv;
 	struct intel_csr *csr;
 	const struct firmware *fw;
 	int ret;

 	dev_priv = container_of(work, typeof(*dev_priv), csr.work);
 	csr = &dev_priv->csr;

 	ret = request_firmware(&fw, dev_priv->csr.fw_path,
 			       &dev_priv->dev->pdev->dev);
 	if (!fw)
 		goto out;

 	dev_priv->csr.dmc_payload = parse_csr_fw(dev_priv, fw);
 	if (!dev_priv->csr.dmc_payload)
 		goto out;

 	/* load csr program during system boot, as needed for DC states */
 	intel_csr_load_program(dev_priv);

 out:
 	if (dev_priv->csr.dmc_payload) {
 		intel_display_power_put(dev_priv, POWER_DOMAIN_INIT);

 		DRM_INFO("Finished loading %s (v%u.%u)\n",
 			 dev_priv->csr.fw_path,
 			 CSR_VERSION_MAJOR(csr->version),
 			 CSR_VERSION_MINOR(csr->version));
 	} else {
 		dev_notice(dev_priv->dev->dev,
 			   "Failed to load DMC firmware"
 			   " [" FIRMWARE_URL "],"
 			   " disabling runtime power management.\n");
 	}

 	release_firmware(fw);
 }

 /**
  * intel_csr_ucode_init() - initialize the firmware loading.
  * @dev_priv: i915 drm device.
  *
  * This function is called at the time of loading the display driver to read
  * firmware from a .bin file and copied into a internal memory.
  */
 void intel_csr_ucode_init(struct drm_i915_private *dev_priv)
 {
 	struct intel_csr *csr = &dev_priv->csr;

 	INIT_WORK(&dev_priv->csr.work, csr_load_work_fn);

 	if (!HAS_CSR(dev_priv))
 		return;

 	if (IS_SKYLAKE(dev_priv) || IS_KABYLAKE(dev_priv))
 		csr->fw_path = I915_CSR_SKL;
 	else if (IS_BROXTON(dev_priv))
 		csr->fw_path = I915_CSR_BXT;
 	else {
 		DRM_ERROR("Unexpected: no known CSR firmware for platform\n");
 		return;
 	}

 	DRM_DEBUG_KMS("Loading %s\n", csr->fw_path);

 	/*
 	 * Obtain a runtime pm reference, until CSR is loaded,
 	 * to avoid entering runtime-suspend.
 	 */
 	intel_display_power_get(dev_priv, POWER_DOMAIN_INIT);

 	schedule_work(&dev_priv->csr.work);
 }

 /**
  * intel_csr_ucode_fini() - unload the CSR firmware.
  * @dev_priv: i915 drm device.
  *
  * Firmmware unloading includes freeing the internal momory and reset the
  * firmware loading status.
  */
 void intel_csr_ucode_fini(struct drm_i915_private *dev_priv)
 {
 	if (!HAS_CSR(dev_priv))
 		return;

 	flush_work(&dev_priv->csr.work);

 	kfree(dev_priv->csr.dmc_payload);
 }
	/*
	* Copyright © 2014 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.
	*
	*/
	#include <linux/firmware.h>
	#include "i915_drv.h"
	#include "i915_reg.h"

	/**
	* DOC: csr support for dmc
	*
	* Display Context Save and Restore (CSR) firmware support added from gen9
	* onwards to drive newly added DMC (Display microcontroller) in display
	* engine to save and restore the state of display engine when it enter into
	* low-power state and comes back to normal.
	*
	* Firmware loading status will be one of the below states: FW_UNINITIALIZED,
	* FW_LOADED, FW_FAILED.
	*
	* Once the firmware is written into the registers status will be moved from
	* FW_UNINITIALIZED to FW_LOADED and for any erroneous condition status will
	* be moved to FW_FAILED.
	*/

	#define I915_CSR_SKL "i915/skl_dmc_ver1.bin"
	#define I915_CSR_BXT "i915/bxt_dmc_ver1.bin"

	#define FIRMWARE_URL "https://01.org/linuxgraphics/intel-linux-graphics-firmwares"

	MODULE_FIRMWARE(I915_CSR_SKL);
	MODULE_FIRMWARE(I915_CSR_BXT);

	#define SKL_CSR_VERSION_REQUIRED CSR_VERSION(1, 23)

	#define CSR_MAX_FW_SIZE 0x2FFF
	#define CSR_DEFAULT_FW_OFFSET 0xFFFFFFFF

	struct intel_css_header {
	/* 0x09 for DMC */
	uint32_t module_type;

	/* Includes the DMC specific header in dwords */
	uint32_t header_len;

	/* always value would be 0x10000 */
	uint32_t header_ver;

	/* Not used */
	uint32_t module_id;

	/* Not used */
	uint32_t module_vendor;

	/* in YYYYMMDD format */
	uint32_t date;

	/* Size in dwords (CSS_Headerlen + PackageHeaderLen + dmc FWsLen)/4 */
	uint32_t size;

	/* Not used */
	uint32_t key_size;

	/* Not used */
	uint32_t modulus_size;

	/* Not used */
	uint32_t exponent_size;

	/* Not used */
	uint32_t reserved1[12];

	/* Major Minor */
	uint32_t version;

	/* Not used */
	uint32_t reserved2[8];

	/* Not used */
	uint32_t kernel_header_info;
	} __packed;

	struct intel_fw_info {
	uint16_t reserved1;

	/* Stepping (A, B, C, ..., ). is a wildcard */
	char stepping;

	/* Sub-stepping (0, 1, ..., ). is a wildcard */
	char substepping;

	uint32_t offset;
	uint32_t reserved2;
	} __packed;

	struct intel_package_header {
	/* DMC container header length in dwords */
	unsigned char header_len;

	/* always value would be 0x01 */
	unsigned char header_ver;

	unsigned char reserved[10];

	/* Number of valid entries in the FWInfo array below */
	uint32_t num_entries;

	struct intel_fw_info fw_info[20];
	} __packed;

	struct intel_dmc_header {
	/* always value would be 0x40403E3E */
	uint32_t signature;

	/* DMC binary header length */
	unsigned char header_len;

	/* 0x01 */
	unsigned char header_ver;

	/* Reserved */
	uint16_t dmcc_ver;

	/* Major, Minor */
	uint32_t project;

	/* Firmware program size (excluding header) in dwords */
	uint32_t fw_size;

	/* Major Minor version */
	uint32_t fw_version;

	/* Number of valid MMIO cycles present. */
	uint32_t mmio_count;

	/* MMIO address */
	uint32_t mmioaddr[8];

	/* MMIO data */
	uint32_t mmiodata[8];

	/* FW filename */
	unsigned char dfile[32];

	uint32_t reserved1[2];
	} __packed;

	struct stepping_info {
	char stepping;
	char substepping;
	};

	/*
	* Kabylake derivated from Skylake H0, so SKL H0
	* is the right firmware for KBL A0 (revid 0).
	*/
	static const struct stepping_info kbl_stepping_info[] = {
	{'H', '0'}, {'I', '0'}
	};

	static const struct stepping_info skl_stepping_info[] = {
	{'A', '0'}, {'B', '0'}, {'C', '0'},
	{'D', '0'}, {'E', '0'}, {'F', '0'},
	{'G', '0'}, {'H', '0'}, {'I', '0'}
	};

	static const struct stepping_info bxt_stepping_info[] = {
	{'A', '0'}, {'A', '1'}, {'A', '2'},
	{'B', '0'}, {'B', '1'}, {'B', '2'}
	};

	static const struct stepping_info intel_get_stepping_info(struct drm_device dev)
	{
	const struct stepping_info *si;
	unsigned int size;

	if (IS_KABYLAKE(dev)) {
	size = ARRAY_SIZE(kbl_stepping_info);
	si = kbl_stepping_info;
	} else if (IS_SKYLAKE(dev)) {
	size = ARRAY_SIZE(skl_stepping_info);
	si = skl_stepping_info;
	} else if (IS_BROXTON(dev)) {
	size = ARRAY_SIZE(bxt_stepping_info);
	si = bxt_stepping_info;
	} else {
	return NULL;
	}

	if (INTEL_REVID(dev) < size)
	return si + INTEL_REVID(dev);

	return NULL;
	}

	/**
	* intel_csr_load_program() - write the firmware from memory to register.
	* @dev_priv: i915 drm device.
	*
	* CSR firmware is read from a .bin file and kept in internal memory one time.
	* Everytime display comes back from low power state this function is called to
	* copy the firmware from internal memory to registers.
	*/
	void intel_csr_load_program(struct drm_i915_private *dev_priv)
	{
	u32 *payload = dev_priv->csr.dmc_payload;
	uint32_t i, fw_size;

	if (!IS_GEN9(dev_priv)) {
	DRM_ERROR("No CSR support available for this platform\n");
	return;
	}

	if (!dev_priv->csr.dmc_payload) {
	DRM_ERROR("Tried to program CSR with empty payload\n");
	return;
	}

	fw_size = dev_priv->csr.dmc_fw_size;
	for (i = 0; i < fw_size; i++)
	I915_WRITE(CSR_PROGRAM(i), payload[i]);

	for (i = 0; i < dev_priv->csr.mmio_count; i++) {
	I915_WRITE(dev_priv->csr.mmioaddr[i],
	dev_priv->csr.mmiodata[i]);
	}
	}

	static uint32_t parse_csr_fw(struct drm_i915_private dev_priv,
	const struct firmware *fw)
	{
	struct drm_device *dev = dev_priv->dev;
	struct intel_css_header *css_header;
	struct intel_package_header *package_header;
	struct intel_dmc_header *dmc_header;
	struct intel_csr *csr = &dev_priv->csr;
	const struct stepping_info *stepping_info = intel_get_stepping_info(dev);
	char stepping, substepping;
	uint32_t dmc_offset = CSR_DEFAULT_FW_OFFSET, readcount = 0, nbytes;
	uint32_t i;
	uint32_t *dmc_payload;

	if (!fw)
	return NULL;

	if (!stepping_info) {
	DRM_ERROR("Unknown stepping info, firmware loading failed\n");
	return NULL;
	}

	stepping = stepping_info->stepping;
	substepping = stepping_info->substepping;

	/* Extract CSS Header information*/
	css_header = (struct intel_css_header *)fw->data;
	if (sizeof(struct intel_css_header) !=
	(css_header->header_len * 4)) {
	DRM_ERROR("Firmware has wrong CSS header length %u bytes\n",
	(css_header->header_len * 4));
	return NULL;
	}

	csr->version = css_header->version;

	if ((IS_SKYLAKE(dev) \|\| IS_KABYLAKE(dev)) &&
	csr->version < SKL_CSR_VERSION_REQUIRED) {
	DRM_INFO("Refusing to load old Skylake DMC firmware v%u.%u,"
	" please upgrade to v%u.%u or later"
	" [" FIRMWARE_URL "].\n",
	CSR_VERSION_MAJOR(csr->version),
	CSR_VERSION_MINOR(csr->version),
	CSR_VERSION_MAJOR(SKL_CSR_VERSION_REQUIRED),
	CSR_VERSION_MINOR(SKL_CSR_VERSION_REQUIRED));
	return NULL;
	}

	readcount += sizeof(struct intel_css_header);

	/* Extract Package Header information*/
	package_header = (struct intel_package_header *)
	&fw->data[readcount];
	if (sizeof(struct intel_package_header) !=
	(package_header->header_len * 4)) {
	DRM_ERROR("Firmware has wrong package header length %u bytes\n",
	(package_header->header_len * 4));
	return NULL;
	}
	readcount += sizeof(struct intel_package_header);

	/* Search for dmc_offset to find firware binary. */
	for (i = 0; i < package_header->num_entries; i++) {
	if (package_header->fw_info[i].substepping == '*' &&
	stepping == package_header->fw_info[i].stepping) {
	dmc_offset = package_header->fw_info[i].offset;
	break;
	} else if (stepping == package_header->fw_info[i].stepping &&
	substepping == package_header->fw_info[i].substepping) {
	dmc_offset = package_header->fw_info[i].offset;
	break;
	} else if (package_header->fw_info[i].stepping == '*' &&
	package_header->fw_info[i].substepping == '*')
	dmc_offset = package_header->fw_info[i].offset;
	}
	if (dmc_offset == CSR_DEFAULT_FW_OFFSET) {
	DRM_ERROR("Firmware not supported for %c stepping\n", stepping);
	return NULL;
	}
	readcount += dmc_offset;

	/* Extract dmc_header information. */
	dmc_header = (struct intel_dmc_header *)&fw->data[readcount];
	if (sizeof(struct intel_dmc_header) != (dmc_header->header_len)) {
	DRM_ERROR("Firmware has wrong dmc header length %u bytes\n",
	(dmc_header->header_len));
	return NULL;
	}
	readcount += sizeof(struct intel_dmc_header);

	/* Cache the dmc header info. */
	if (dmc_header->mmio_count > ARRAY_SIZE(csr->mmioaddr)) {
	DRM_ERROR("Firmware has wrong mmio count %u\n",
	dmc_header->mmio_count);
	return NULL;
	}
	csr->mmio_count = dmc_header->mmio_count;
	for (i = 0; i < dmc_header->mmio_count; i++) {
	if (dmc_header->mmioaddr[i] < CSR_MMIO_START_RANGE \|\|
	dmc_header->mmioaddr[i] > CSR_MMIO_END_RANGE) {
	DRM_ERROR(" Firmware has wrong mmio address 0x%x\n",
	dmc_header->mmioaddr[i]);
	return NULL;
	}
	csr->mmioaddr[i] = _MMIO(dmc_header->mmioaddr[i]);
	csr->mmiodata[i] = dmc_header->mmiodata[i];
	}

	/* fw_size is in dwords, so multiplied by 4 to convert into bytes. */
	nbytes = dmc_header->fw_size * 4;
	if (nbytes > CSR_MAX_FW_SIZE) {
	DRM_ERROR("CSR firmware too big (%u) bytes\n", nbytes);
	return NULL;
	}
	csr->dmc_fw_size = dmc_header->fw_size;

	dmc_payload = kmalloc(nbytes, GFP_KERNEL);
	if (!dmc_payload) {
	DRM_ERROR("Memory allocation failed for dmc payload\n");
	return NULL;
	}

	memcpy(dmc_payload, &fw->data[readcount], nbytes);

	return dmc_payload;
	}

	static void csr_load_work_fn(struct work_struct *work)
	{
	struct drm_i915_private *dev_priv;
	struct intel_csr *csr;
	const struct firmware *fw;
	int ret;

	dev_priv = container_of(work, typeof(*dev_priv), csr.work);
	csr = &dev_priv->csr;

	ret = request_firmware(&fw, dev_priv->csr.fw_path,
	&dev_priv->dev->pdev->dev);
	if (!fw)
	goto out;

	dev_priv->csr.dmc_payload = parse_csr_fw(dev_priv, fw);
	if (!dev_priv->csr.dmc_payload)
	goto out;

	/* load csr program during system boot, as needed for DC states */
	intel_csr_load_program(dev_priv);

	out:
	if (dev_priv->csr.dmc_payload) {
	intel_display_power_put(dev_priv, POWER_DOMAIN_INIT);

	DRM_INFO("Finished loading %s (v%u.%u)\n",
	dev_priv->csr.fw_path,
	CSR_VERSION_MAJOR(csr->version),
	CSR_VERSION_MINOR(csr->version));
	} else {
	dev_notice(dev_priv->dev->dev,
	"Failed to load DMC firmware"
	" [" FIRMWARE_URL "],"
	" disabling runtime power management.\n");
	}

	release_firmware(fw);
	}

	/**
	* intel_csr_ucode_init() - initialize the firmware loading.
	* @dev_priv: i915 drm device.
	*
	* This function is called at the time of loading the display driver to read
	* firmware from a .bin file and copied into a internal memory.
	*/
	void intel_csr_ucode_init(struct drm_i915_private *dev_priv)
	{
	struct intel_csr *csr = &dev_priv->csr;

	INIT_WORK(&dev_priv->csr.work, csr_load_work_fn);

	if (!HAS_CSR(dev_priv))
	return;

	if (IS_SKYLAKE(dev_priv) \|\| IS_KABYLAKE(dev_priv))
	csr->fw_path = I915_CSR_SKL;
	else if (IS_BROXTON(dev_priv))
	csr->fw_path = I915_CSR_BXT;
	else {
	DRM_ERROR("Unexpected: no known CSR firmware for platform\n");
	return;
	}

	DRM_DEBUG_KMS("Loading %s\n", csr->fw_path);

	/*
	* Obtain a runtime pm reference, until CSR is loaded,
	* to avoid entering runtime-suspend.
	*/
	intel_display_power_get(dev_priv, POWER_DOMAIN_INIT);

	schedule_work(&dev_priv->csr.work);
	}

	/**
	* intel_csr_ucode_fini() - unload the CSR firmware.
	* @dev_priv: i915 drm device.
	*
	* Firmmware unloading includes freeing the internal momory and reset the
	* firmware loading status.
	*/
	void intel_csr_ucode_fini(struct drm_i915_private *dev_priv)
	{
	if (!HAS_CSR(dev_priv))
	return;

	flush_work(&dev_priv->csr.work);

	kfree(dev_priv->csr.dmc_payload);
	}