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pci: add readme to pci_drv, adjust acpi_drv README
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Alexander Boettcher
Christian Helmuth
parent
51b79d7da6
commit
dd7ddae0e9
@ -3,12 +3,12 @@ This directory contains an implementation of a simple ACPI parser
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Behavior
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--------
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This server should be used when using a kernel (like Fiasco.OC or Nova) that
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takes advantage of x86's APIC. The server traverses the ACPI tables and sets the
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interrupt line of devices within the PCI config space to the GSIs found in the
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ACPI tables. The 'MADT' table is parsed by the server as well, enabling clients
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to use the correct IRQ when 'Interrupt Override' structures are found wihtin the
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table.
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This server should be used when using a kernel (like Fiasco.OC, Nova,
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base_hw x86_64) that takes advantage of x86's APIC. The server traverses the
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ACPI tables and sets the interrupt line of devices within the PCI config space
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to the GSIs found in the ACPI tables. The 'MADT' table is parsed by the server
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as well, enabling clients to use the correct IRQ when 'Interrupt Override'
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structures are found wihtin the table.
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Usage
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-----
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@ -20,15 +20,18 @@ since this will be used as a slave of the 'acpi_drv'. You still must load the
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Configuration snipped (please note that IRQ service requests of the 'timer' are
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routed to the ACPI-driver):
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!<start name="acpi">
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! <resource name="RAM" quantum="2M"/>
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! <binary name="acpi_drv"/>
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!<start name="acpi_drv">
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! <resource name="RAM" quantum="2M" constrain_phys="yes"/>
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! <provides>
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! <service name="PCI"/>
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! <service name="IRQ" />
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! </provides>
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! <config>
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! <policy label="acpi_drv">
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! <pci class="ALL"/>
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! </policy>
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! </config>
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! <route>
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! <service name="PCI"> <any-child /> </service>
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! <any-service> <parent/> <any-child /> </any-service>
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! </route>
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!</start>
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@ -37,14 +40,15 @@ routed to the ACPI-driver):
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! <resource name="RAM" quantum="1M"/>
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! <provides><service name="Timer"/></provides>
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! <route>
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! <service name="IRQ"><child name="acpi" /></service>
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! <service name="IRQ"><child name="acpi_drv" /></service>
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! <any-service> <parent /> <any-child /></any-service>
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! </route>
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!</start>
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Limitations and known issues
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----------------------------
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Currently there is no interface to set the interrupt mode for Irq_sessions
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(e.g., level or edge triggered). This is required by Fiasco.OCs kernel
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interface. We regard this as future work.
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The 'config' node on the 'acpi_drv' requires an policy entry that permits the
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'acpi_drv' to iterate over all pci devices in order to rewrite the
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interrupt numbers according to the 'MADT' table. Furthermore the whole 'config'
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node will be passed on to the 'pci_drv' which obtains from it the required
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policy for each client. Additionally the constrain_phys attribute is a
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feature of init, which applies to the pci_drv. Please read the 'pci_drv'
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README for more details.
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118
repos/os/src/drivers/pci/README
Normal file
118
repos/os/src/drivers/pci/README
Normal file
@ -0,0 +1,118 @@
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This directory contains the implementation of Genode's PCI driver.
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Behavior
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--------
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On startup the driver scans the PCI bus hierarchy and stores the found devices.
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Per client a policy must be configured that states which client can
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access certain devices to form a virtual pci bus per client. The client may
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iterate through the virtual pci bus using the 'first' and 'next' methods of
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the pci_session interface to discover all available devices of the virtual bus.
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Non PCI devices may be discovered by using 'device' of the pci_session
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interface. As a result of the discovery a client obtains a device capability.
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With the device capability the resources of the devices can be obtained, e.g.
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io_port, io_mem and irq of the pci_device interface.
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Policy usage
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------------
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A policy may contain several nodes describing several devices. The entries of
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a policy may describe PCI devices as non PCI devices. A PCI device is
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explicitly configured by the triple 'bus', 'device', 'function':
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!<start name="pci_drv">
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! <resource name="RAM" quantum="8M" constrain_phys="yes"/>
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! ...
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! <config>
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! <policy label="usb_drv">
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! <pci bus="0" device="19" function="0"/>
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! <pci bus="0" device="18" function="3"/>
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! </policy>
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! </config>
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!</start>
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or more fuzzy by a device class alias:
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!<start name="pci_drv">
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! <resource name="RAM" quantum="8M" constrain_phys="yes"/>
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! ...
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! <config>
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! <policy label="usb_drv">
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! <pci class="USB"/>
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! </policy>
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! </config>
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!</start>
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Non PCI devices, as the PS2 controller are named by a "device" node in the policy:
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!<start name="pci_drv">
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! <resource name="RAM" quantum="8M" constrain_phys="yes"/>
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! <config>
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! <policy label="ps_drv">
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! <device name="PS2/>
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! </policy>
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! </config>
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!</start>
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The first entry ('pci' or 'dev') of the policy node that matches will grant
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access of a device or device class to the client. Subsequent entries will not
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be checked. If a 'bus', 'device', 'function' triple was specified in one of the
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policies and in another policy a fuzzy pci class alias which would include
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the device specified by the triple, the device will not appear during device
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discovery by the client with the fuzzy pci class policy.
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By default the driver will try to use MSIs if the device and the used kernel
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supports it. This behaviour can be overwritten:
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!<start name="pci_drv">
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! <resource name="RAM" quantum="8M" constrain_phys="yes"/>
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! <config>
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! <policy label="nic_drv" irq_mode="nomsi">
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! ...
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! </policy>
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! </config>
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!</start>
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The constrain_phys attribute is evaluated by init. If set to "yes" it
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permits a component, the pci driver, to restrict the allocation of memory to
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specific physical RAM ranges. The PCI driver uses this feature to ensure that
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the allocation of DMA capable memory consider several restrictions. For
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example, some drivers, as the UHCI controller, requires a
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physical memory address below 4G. Another example is that on 32bit hosts
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physical to virtual identical mappings of DMA memory for the device_pd
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(required when IOMMU is used) must be below the kernel memory boundary (3G).
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Supported PCI class aliases
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---------------------------
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The following class names are supported which corresponds to the
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specified PCI class(C), subclass(S) and programming interface(P):
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alias C S P
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*********************
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ALL 0x0 0x00 0x0
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AHCI 0x1 0x06 0x0
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AUDIO 0x4 0x00 0x0
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ETHERNET 0x2 0x00 0x0
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USB 0xc 0x03 0x0
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VGA 0x3 0x00 0x0
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WIFI 0x2 0x80 0x0
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Supported non PCI devices
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-------------------------
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The driver provides for the PS2 controller the IO_PORT and IRQ resources.
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!<start name="pci_drv">
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! <resource name="RAM" quantum="8M" constrain_phys="yes"/>
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! <config>
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! <policy label="ps_drv">
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! <dev name="PS2/>
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! </policy>
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! </config>
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!</start>
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