drivers/gpu/drm/i915/intel_csr.c - arm/linux - Git at Google

 /*
  * 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.
  */

 #define I915_CSR_GLK "i915/glk_dmc_ver1_04.bin"
 #define GLK_CSR_VERSION_REQUIRED	CSR_VERSION(1, 4)

 #define I915_CSR_CNL "i915/cnl_dmc_ver1_04.bin"
 #define CNL_CSR_VERSION_REQUIRED	CSR_VERSION(1, 4)

 #define I915_CSR_KBL "i915/kbl_dmc_ver1_01.bin"
 MODULE_FIRMWARE(I915_CSR_KBL);
 #define KBL_CSR_VERSION_REQUIRED	CSR_VERSION(1, 1)

 #define I915_CSR_SKL "i915/skl_dmc_ver1_26.bin"
 MODULE_FIRMWARE(I915_CSR_SKL);
 #define SKL_CSR_VERSION_REQUIRED	CSR_VERSION(1, 26)

 #define I915_CSR_BXT "i915/bxt_dmc_ver1_07.bin"
 MODULE_FIRMWARE(I915_CSR_BXT);
 #define BXT_CSR_VERSION_REQUIRED	CSR_VERSION(1, 7)

 #define FIRMWARE_URL  "https://01.org/linuxgraphics/downloads/firmware"


 #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;
 };

 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'},
 	{'J', '0'}, {'K', '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 no_stepping_info = { '*', '*' };

 static const struct stepping_info *
 intel_get_stepping_info(struct drm_i915_private *dev_priv)
 {
 	const struct stepping_info *si;
 	unsigned int size;

 	if (IS_SKYLAKE(dev_priv)) {
 		size = ARRAY_SIZE(skl_stepping_info);
 		si = skl_stepping_info;
 	} else if (IS_BROXTON(dev_priv)) {
 		size = ARRAY_SIZE(bxt_stepping_info);
 		si = bxt_stepping_info;
 	} else {
 		size = 0;
 	}

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

 	return &no_stepping_info;
 }

 static void gen9_set_dc_state_debugmask(struct drm_i915_private *dev_priv)
 {
 	uint32_t val, mask;

 	mask = DC_STATE_DEBUG_MASK_MEMORY_UP;

 	if (IS_GEN9_LP(dev_priv))
 		mask |= DC_STATE_DEBUG_MASK_CORES;

 	/* The below bit doesn't need to be cleared ever afterwards */
 	val = I915_READ(DC_STATE_DEBUG);
 	if ((val & mask) != mask) {
 		val |= mask;
 		I915_WRITE(DC_STATE_DEBUG, val);
 		POSTING_READ(DC_STATE_DEBUG);
 	}
 }

 /**
  * 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 (!HAS_CSR(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]);
 	}

 	dev_priv->csr.dc_state = 0;

 	gen9_set_dc_state_debugmask(dev_priv);
 }

 static uint32_t *parse_csr_fw(struct drm_i915_private *dev_priv,
 			      const struct firmware *fw)
 {
 	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 *si = intel_get_stepping_info(dev_priv);
 	uint32_t dmc_offset = CSR_DEFAULT_FW_OFFSET, readcount = 0, nbytes;
 	uint32_t i;
 	uint32_t *dmc_payload;
 	uint32_t required_version;

 	if (!fw)
 		return NULL;

 	/* 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_CANNONLAKE(dev_priv)) {
 		required_version = CNL_CSR_VERSION_REQUIRED;
 	} else if (IS_GEMINILAKE(dev_priv)) {
 		required_version = GLK_CSR_VERSION_REQUIRED;
 	} else if (IS_KABYLAKE(dev_priv) || IS_COFFEELAKE(dev_priv)) {
 		required_version = KBL_CSR_VERSION_REQUIRED;
 	} else if (IS_SKYLAKE(dev_priv)) {
 		required_version = SKL_CSR_VERSION_REQUIRED;
 	} else if (IS_BROXTON(dev_priv)) {
 		required_version = BXT_CSR_VERSION_REQUIRED;
 	} else {
 		MISSING_CASE(INTEL_REVID(dev_priv));
 		required_version = 0;
 	}

 	if (csr->version != required_version) {
 		DRM_INFO("Refusing to load DMC firmware v%u.%u,"
 			 " please use v%u.%u [" FIRMWARE_URL "].\n",
 			 CSR_VERSION_MAJOR(csr->version),
 			 CSR_VERSION_MINOR(csr->version),
 			 CSR_VERSION_MAJOR(required_version),
 			 CSR_VERSION_MINOR(required_version));
 		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 == '*' &&
 		    si->stepping == package_header->fw_info[i].stepping) {
 			dmc_offset = package_header->fw_info[i].offset;
 			break;
 		} else if (si->stepping == package_header->fw_info[i].stepping &&
 			   si->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",
 			  si->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;
 	}

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

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

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

 	request_firmware(&fw, dev_priv->csr.fw_path, &dev_priv->drm.pdev->dev);
 	if (fw)
 		dev_priv->csr.dmc_payload = parse_csr_fw(dev_priv, fw);

 	if (dev_priv->csr.dmc_payload) {
 		intel_csr_load_program(dev_priv);

 		intel_display_power_put(dev_priv, POWER_DOMAIN_INIT);

 		DRM_INFO("Finished loading DMC firmware %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->drm.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_CANNONLAKE(dev_priv))
 		csr->fw_path = I915_CSR_CNL;
 	else if (IS_GEMINILAKE(dev_priv))
 		csr->fw_path = I915_CSR_GLK;
 	else if (IS_KABYLAKE(dev_priv) || IS_COFFEELAKE(dev_priv))
 		csr->fw_path = I915_CSR_KBL;
 	else if (IS_SKYLAKE(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_suspend() - prepare CSR firmware before system suspend
  * @dev_priv: i915 drm device
  *
  * Prepare the DMC firmware before entering system suspend. This includes
  * flushing pending work items and releasing any resources acquired during
  * init.
  */
 void intel_csr_ucode_suspend(struct drm_i915_private *dev_priv)
 {
 	if (!HAS_CSR(dev_priv))
 		return;

 	flush_work(&dev_priv->csr.work);

 	/* Drop the reference held in case DMC isn't loaded. */
 	if (!dev_priv->csr.dmc_payload)
 		intel_display_power_put(dev_priv, POWER_DOMAIN_INIT);
 }

 /**
  * intel_csr_ucode_resume() - init CSR firmware during system resume
  * @dev_priv: i915 drm device
  *
  * Reinitialize the DMC firmware during system resume, reacquiring any
  * resources released in intel_csr_ucode_suspend().
  */
 void intel_csr_ucode_resume(struct drm_i915_private *dev_priv)
 {
 	if (!HAS_CSR(dev_priv))
 		return;

 	/*
 	 * Reacquire the reference to keep RPM disabled in case DMC isn't
 	 * loaded.
 	 */
 	if (!dev_priv->csr.dmc_payload)
 		intel_display_power_get(dev_priv, POWER_DOMAIN_INIT);
 }

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

 	intel_csr_ucode_suspend(dev_priv);

 	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.
	*/

	#define I915_CSR_GLK "i915/glk_dmc_ver1_04.bin"
	#define GLK_CSR_VERSION_REQUIRED CSR_VERSION(1, 4)

	#define I915_CSR_CNL "i915/cnl_dmc_ver1_04.bin"
	#define CNL_CSR_VERSION_REQUIRED CSR_VERSION(1, 4)

	#define I915_CSR_KBL "i915/kbl_dmc_ver1_01.bin"
	MODULE_FIRMWARE(I915_CSR_KBL);
	#define KBL_CSR_VERSION_REQUIRED CSR_VERSION(1, 1)

	#define I915_CSR_SKL "i915/skl_dmc_ver1_26.bin"
	MODULE_FIRMWARE(I915_CSR_SKL);
	#define SKL_CSR_VERSION_REQUIRED CSR_VERSION(1, 26)

	#define I915_CSR_BXT "i915/bxt_dmc_ver1_07.bin"
	MODULE_FIRMWARE(I915_CSR_BXT);
	#define BXT_CSR_VERSION_REQUIRED CSR_VERSION(1, 7)

	#define FIRMWARE_URL "https://01.org/linuxgraphics/downloads/firmware"




	#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;
	};

	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'},
	{'J', '0'}, {'K', '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 no_stepping_info = { '', '' };

	static const struct stepping_info *
	intel_get_stepping_info(struct drm_i915_private *dev_priv)
	{
	const struct stepping_info *si;
	unsigned int size;

	if (IS_SKYLAKE(dev_priv)) {
	size = ARRAY_SIZE(skl_stepping_info);
	si = skl_stepping_info;
	} else if (IS_BROXTON(dev_priv)) {
	size = ARRAY_SIZE(bxt_stepping_info);
	si = bxt_stepping_info;
	} else {
	size = 0;
	}

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

	return &no_stepping_info;
	}

	static void gen9_set_dc_state_debugmask(struct drm_i915_private *dev_priv)
	{
	uint32_t val, mask;

	mask = DC_STATE_DEBUG_MASK_MEMORY_UP;

	if (IS_GEN9_LP(dev_priv))
	mask \|= DC_STATE_DEBUG_MASK_CORES;

	/* The below bit doesn't need to be cleared ever afterwards */
	val = I915_READ(DC_STATE_DEBUG);
	if ((val & mask) != mask) {
	val \|= mask;
	I915_WRITE(DC_STATE_DEBUG, val);
	POSTING_READ(DC_STATE_DEBUG);
	}
	}

	/**
	* 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 (!HAS_CSR(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]);
	}

	dev_priv->csr.dc_state = 0;

	gen9_set_dc_state_debugmask(dev_priv);
	}

	static uint32_t parse_csr_fw(struct drm_i915_private dev_priv,
	const struct firmware *fw)
	{
	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 *si = intel_get_stepping_info(dev_priv);
	uint32_t dmc_offset = CSR_DEFAULT_FW_OFFSET, readcount = 0, nbytes;
	uint32_t i;
	uint32_t *dmc_payload;
	uint32_t required_version;

	if (!fw)
	return NULL;

	/* 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_CANNONLAKE(dev_priv)) {
	required_version = CNL_CSR_VERSION_REQUIRED;
	} else if (IS_GEMINILAKE(dev_priv)) {
	required_version = GLK_CSR_VERSION_REQUIRED;
	} else if (IS_KABYLAKE(dev_priv) \|\| IS_COFFEELAKE(dev_priv)) {
	required_version = KBL_CSR_VERSION_REQUIRED;
	} else if (IS_SKYLAKE(dev_priv)) {
	required_version = SKL_CSR_VERSION_REQUIRED;
	} else if (IS_BROXTON(dev_priv)) {
	required_version = BXT_CSR_VERSION_REQUIRED;
	} else {
	MISSING_CASE(INTEL_REVID(dev_priv));
	required_version = 0;
	}

	if (csr->version != required_version) {
	DRM_INFO("Refusing to load DMC firmware v%u.%u,"
	" please use v%u.%u [" FIRMWARE_URL "].\n",
	CSR_VERSION_MAJOR(csr->version),
	CSR_VERSION_MINOR(csr->version),
	CSR_VERSION_MAJOR(required_version),
	CSR_VERSION_MINOR(required_version));
	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 == '*' &&
	si->stepping == package_header->fw_info[i].stepping) {
	dmc_offset = package_header->fw_info[i].offset;
	break;
	} else if (si->stepping == package_header->fw_info[i].stepping &&
	si->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",
	si->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;
	}

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

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

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

	request_firmware(&fw, dev_priv->csr.fw_path, &dev_priv->drm.pdev->dev);
	if (fw)
	dev_priv->csr.dmc_payload = parse_csr_fw(dev_priv, fw);

	if (dev_priv->csr.dmc_payload) {
	intel_csr_load_program(dev_priv);

	intel_display_power_put(dev_priv, POWER_DOMAIN_INIT);

	DRM_INFO("Finished loading DMC firmware %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->drm.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_CANNONLAKE(dev_priv))
	csr->fw_path = I915_CSR_CNL;
	else if (IS_GEMINILAKE(dev_priv))
	csr->fw_path = I915_CSR_GLK;
	else if (IS_KABYLAKE(dev_priv) \|\| IS_COFFEELAKE(dev_priv))
	csr->fw_path = I915_CSR_KBL;
	else if (IS_SKYLAKE(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_suspend() - prepare CSR firmware before system suspend
	* @dev_priv: i915 drm device
	*
	* Prepare the DMC firmware before entering system suspend. This includes
	* flushing pending work items and releasing any resources acquired during
	* init.
	*/
	void intel_csr_ucode_suspend(struct drm_i915_private *dev_priv)
	{
	if (!HAS_CSR(dev_priv))
	return;

	flush_work(&dev_priv->csr.work);

	/* Drop the reference held in case DMC isn't loaded. */
	if (!dev_priv->csr.dmc_payload)
	intel_display_power_put(dev_priv, POWER_DOMAIN_INIT);
	}

	/**
	* intel_csr_ucode_resume() - init CSR firmware during system resume
	* @dev_priv: i915 drm device
	*
	* Reinitialize the DMC firmware during system resume, reacquiring any
	* resources released in intel_csr_ucode_suspend().
	*/
	void intel_csr_ucode_resume(struct drm_i915_private *dev_priv)
	{
	if (!HAS_CSR(dev_priv))
	return;

	/*
	* Reacquire the reference to keep RPM disabled in case DMC isn't
	* loaded.
	*/
	if (!dev_priv->csr.dmc_payload)
	intel_display_power_get(dev_priv, POWER_DOMAIN_INIT);
	}

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

	intel_csr_ucode_suspend(dev_priv);

	kfree(dev_priv->csr.dmc_payload);
	}