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GuC WOPCM registers are write-once registers. Current driver code accesses these registers without checking the accessibility to these registers which will lead to unpredictable driver behaviors if these registers were touch by other components (such as faulty BIOS code). This patch moves the GuC WOPCM registers updating code into intel_wopcm.c and adds check before and after the update to GuC WOPCM registers so that we can make sure the driver is in a known state after writing to these write-once registers. v6: - Made sure module reloading won't bug the kernel while doing locking status checking v7: - Fixed patch format issues v8: - Fixed coding style issue on register lock bit macro definition (Sagar) v9: - Avoided to use redundant !! to cast uint to bool (Chris) - Return error code instead of GEM_BUG_ON for locked with invalid register values case (Sagar) - Updated guc_wopcm_hw_init to use guc_wopcm as first parameter (Michal) - Added code to set and validate the HuC_LOADING_AGENT_GUC bit in GuC WOPCM offset register based on the presence of HuC firmware (Michal) - Use bit fields instead of macros for GuC WOPCM flags (Michal) v10: - Refined variable names, removed redundant comments (Joonas) - Introduced lockable_reg to handle the write once register write and propagate the write error to caller (Joonas) - Used lockable_reg abstraction to avoid locking bit check on generic i915_reg_t (Michal) - Added log message for error paths (Michal) - Removed hw_updated flag and only relies on real hardware status v11: - Replaced lockable_reg with simplified function (Michal) - Used new macros for locking bits of WOPCM size/offset registers instead of using BIT(0) directly (Michal) - use intel_wopcm_init_hw() called from intel_gem_init_hw() to do GuC WOPCM register setup instead of calling from intel_uc_init_hw() (Michal) v12: - Updated function kernel-doc to align with code changes (Michal) - Updated code to use wopcm pointer directly (Michal) v13: - Updated the ordering of s-o-b/cc/r-b tags (Sagar) BSpec: 10875, 10833 Signed-off-by: Jackie Li <yaodong.li@intel.com> Cc: Michal Wajdeczko <michal.wajdeczko@intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com> (v11) Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> (v12) Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/1520987574-19351-5-git-send-email-yaodong.li@intel.com
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.