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Kernel/PCI: Introduce a new ECAM access mechanism

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Now the kernel supports 2 ECAM access methods.
MMIOAccess was renamed to WindowedMMIOAccess and is what we had until
now - each device that is detected on boot is assigned to a
memory-mapped window, so IO operations on multiple devices can occur
simultaneously due to creating multiple virtual mappings, hence the name
is a memory-mapped window.

This commit adds a new class called MMIOAccess (not to be confused with
the old MMIOAccess class). This class creates one memory-mapped window.
On each IO operation on a configuration space of a device, it maps the
requested PCI bus region to that window. Therefore it holds a SpinLock
during the operation to ensure that no other PCI bus region was mapped
during the call.

A user can choose to either use PCI ECAM with memory-mapped window
for each device, or for an entire bus. By default, the kernel prefers to
map the entire PCI bus region.
This commit is contained in:
Liav A 2021-04-03 16:46:04 +03:00 • committed by Andreas Kling
parent 441e374396
commit 8abbb7e090
11 changed files with 320 additions and 100 deletions
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2
Kernel/PCI/IOAccess.h
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@ -40,7 +40,7 @@ protected:
private:
virtual void enumerate_hardware(Function<void(Address, ID)>) override;
virtual const char* access_type() const override { return "IO-Access"; };
virtual const char* access_type() const override { return "IOAccess"; };
virtual uint32_t segment_count() const override { return 1; };
virtual void write8_field(Address address, u32, u8) override final;
virtual void write16_field(Address address, u32, u16) override final;