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drm/i915/de: Add a simple intel_de_read64_2x32()

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intel_de_read64_2x32_volatile() is a complex beast because
it needs to deal with volatile register values. For simpler
cases we can simply do a pair normal intel_de_read()s.

My main reason for hating overuse of intel_de_read64_2x32_volatile()
is that it makes register tracepoints confusing. It always
does three accesses in the somewhat weird udw,ldw,udw order,
confusing the reader of the trace. Much more clear if we just
observe the two reads in the natural little endian order.

We also have no non-volatile use case where the LDW and UDW
are stored in non-consecutive registers, so we can just pass
along a single register offset.

v2: Put the function arguments on one line (Jani)

Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20260331154259.24600-10-ville.syrjala@linux.intel.com
This commit is contained in:
Ville Syrjälä 2026-03-31 18:42:56 +03:00
parent 581feef634
commit 57369c91da
1 changed files with 12 additions and 0 deletions
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12
drivers/gpu/drm/i915/display/intel_de.h
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@ -53,6 +53,18 @@ intel_de_read64_2x32_volatile(struct intel_display *display,
return val;
}
static inline u64
intel_de_read64_2x32(struct intel_display *display, i915_reg_t reg)
{
i915_reg_t upper_reg = _MMIO(i915_mmio_reg_offset(reg) + 4);
u32 lower, upper;
lower = intel_de_read(display, reg);
upper = intel_de_read(display, upper_reg);
return (u64)upper << 32 | lower;
}
static inline void
intel_de_posting_read(struct intel_display *display, i915_reg_t reg)
{