[Intel-gfx] [CI v3] drm/i915: do not pass dev_priv to low-level forcewake functions

[Chris Wilson]

Quoting Chris Wilson (2019-03-16 10:00:45)
> From: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
> 
> The only usage we have for it is for the regs pointer. Save a pointer to
> the set and ack registers instead of the register offsets to remove this
> requirement
> 
> v2: Keep passing uncore down to the lowest levels to avoid repeated
> pointer chasing in the innermost loops:
> 
> add/remove: 0/0 grow/shrink: 3/15 up/down: 33/-155 (-122)
> Function                                     old     new   delta
> fw_domain_init                               320     351     +31
> hdmi_port_clock_valid                        319     320      +1
> g4x_pre_enable_dp                            364     365      +1
> ring_request_alloc                          1852    1851      -1
> intel_engine_lookup_user                      50      49      -1
> gen11_irq_handler                            738     737      -1
> __intel_uncore_forcewake_get                 115     112      -3
> intel_uncore_fw_release_timer                198     194      -4
> i915_forcewake_domains                       154     150      -4
> fw_domain_fini                               172     168      -4
> __intel_uncore_forcewake_put                 163     159      -4
> ___force_wake_auto                           138     134      -4
> fw_domains_put                                98      92      -6
> __err_print_to_sgl                          4058    4052      -6
> intel_uncore_forcewake_reset                 459     444     -15
> fw_domains_get                               563     548     -15
> fw_domain_wait_ack_with_fallback             490     450     -40
> fw_domains_get_with_fallback                 875     828     -47

Interestingly, moving the u32 values from intel_uncore to each domain,

        enum forcewake_domains fw_domains_active;
        enum forcewake_domains fw_domains_saved; /* user domains saved for S3 */

-       u32 fw_set;
-       u32 fw_clear;
-       u32 fw_reset;
-
        struct intel_uncore_forcewake_domain {
                enum forcewake_domain_id id;
                enum forcewake_domains mask;
                unsigned int wake_count;
                bool active;
                struct hrtimer timer;
+
+               u32 fw_set;
+               u32 fw_clear;
+               u32 fw_reset;
+
                u32 __iomem *reg_set;
                u32 __iomem *reg_ack;
        } fw_domain[FW_DOMAIN_ID_COUNT];

is a loss as fw_domains_get() instead of shrinking grows,

add/remove: 0/0 grow/shrink: 11/7 up/down: 159/-136 (23)
Function                                     old     new   delta
fw_domain_init                               320     441    +121
fw_domains_get                               563     572      +9
intel_uncore_forcewake_reset                 459     466      +7
fw_domain_fini                               172     176      +4
__intel_uncore_forcewake_get                 115     119      +4
intel_uncore_fw_release_timer                198     201      +3
i915_forcewake_domains                       154     157      +3
__intel_uncore_forcewake_put                 163     166      +3
___force_wake_auto                           138     141      +3
hdmi_port_clock_valid                        319     320      +1
g4x_pre_enable_dp                            364     365      +1
ring_request_alloc                          1852    1851      -1
intel_engine_lookup_user                      50      49      -1
gen11_irq_handler                            738     737      -1
__err_print_to_sgl                          4058    4052      -6
fw_domains_get_with_fallback                 875     852     -23
fw_domain_wait_ack_with_fallback             490     450     -40
intel_uncore_init                           2134    2070     -64

Will be interesting to review later as the picture will be quite
different with a primary intel_uncore, and I expect the shrinkage to
continue (as well as code clarity from improved encapsulation).
-Chris