Documentation: x86 device tree processing and memory map

Add documentation on:
*  FSP Silicon Init
*  How to start the x86 device tree processing for ramstage
*  Disabling the PCI devices
*  Generic PCI device drivers
*  Memory map support

TEST=None

Change-Id: If8f729a0ea1d48db4d5ec1d4ae3ad693e9fe44f0
Signed-off-by: Lee Leahy <leroy.p.leahy@intel.com>
Reviewed-on: https://review.coreboot.org/13718
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>
This commit is contained in:
Lee Leahy 2016-02-14 14:55:29 -08:00 committed by Leroy P Leahy
parent db7410e0a4
commit de8c7e39bc
3 changed files with 287 additions and 3 deletions

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@ -16,6 +16,7 @@
<li><a href="#RequiredFiles">Required Files</a></li>
<li>Enable <a href="#SerialOutput">Serial Output</a></li>
<li>Load the <a href="#SpdData">Memory Timing Data</a></li>
<li><a href="#DisablePciDevices">Disable</a> the PCI devices</li>
</ol>
@ -181,7 +182,33 @@
</ol>
<hr>
<p>Modified: 31 January 2016</p>
<h1><a name="DisablePciDevices">Disable PCI Devices</a></h1>
<p>
Ramstage's BS_DEV_ENUMERATE state displays the PCI vendor and device IDs for all
of the devices in the system. Edit the devicetree.cb file:
</p>
<ol>
<li>Edit the devicetree.cb file:
<ol type="A">
<li>Add an entry for a PCI device.function and turn it off. The entry
should look similar to:
<pre><code>device pci 14.0 off end</code></pre>
</li>
<li>Turn on the devices for:
<ul>
<li>Memory Controller</li>
<li>Debug serial device</li>
</ul>
</li>
</ol>
</li>
<li>Debug until the BS_DEV_ENUMERATE state shows the proper state for all of the devices</li>
</ol>
<hr>
<p>Modified: 15 February 2016</p>
</body>
</html>

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@ -26,6 +26,12 @@
<li>Add the <a href="#MemoryInit">MemoryInit</a> Support</li>
</ol>
</li>
<li><a href="#Ramstage">Ramstage</a>
<ol type="A">
<li><a href="#DeviceTree">Start Device Tree Processing</a></li>
<li>Set up the <a href="#MemoryMap">Memory Map"</a></li>
</ol>
</li>
</ol>
@ -382,6 +388,176 @@ Use the following steps to debug the call to TempRamInit:
<hr>
<p>Modified: 31 January 2016</p>
<h1><a name="Ramstage">Ramstage</a></h1>
<h2><a name="DeviceTree">Start Device Tree Processing</a></h2>
<p>
The src/mainboard/&lt;Vendor&gt;/&lt;Board&gt;/devicetree.cb file drives the
execution during ramstage. This file is processed by the util/sconfig utility
to generate build/mainboard/&lt;Vendor&gt;/&lt;Board&gt;/static.c. The various
state routines in
src/lib/<a target="_blank" href="http://review.coreboot.org/gitweb?p=coreboot.git;a=blob;f=src/lib/hardwaremain.c;hb=HEAD#l128">hardwaremain.c</a>
call dev_* routines which use the tables in static.c to locate operation tables
associated with the various chips and devices. After location the operation
tables, the state routines call one or more functions depending upon the
state of the state machine.
</p>
<h3><a name="ChipOperations">Chip Operations</a></h3>
<p>
Kick-starting the ramstage state machine requires creating the operation table
for the chip listed in devicetree.cb:
</p>
<ol>
<li>Edit src/soc/&lt;SoC Vendor&gt;/&lt;SoC Family&gt;/chip.c:
<ol type="A">
<li>
This chip's operation table has the name
soc_&lt;SoC Vendor&gt;_&lt;SoC Family&gt;_ops which is derived from the
chip path specified in the devicetree.cb file.
</li>
<li>Use the CHIP_NAME macro to specify the name for the chip</li>
<li>For FSP 1.1, specify a .init routine which calls intel_silicon_init</li>
</ol>
</li>
<li>Edit src/soc/&lt;SoC Vendor&gt;/&lt;SoC Family&gt;/Makefile.inc and add chip.c to ramstage</li>
</ol>
<h3>Domain Operations</h3>
<p>
coreboot uses the domain operation table to initiate operations on all of the
devices in the domain. By default coreboot enables all PCI devices which it
finds. Listing a device in devicetree.cb gives the board vendor control over
the device state. Non-PCI devices may also be listed under PCI device such as
the LPC bus or SMbus devices.
</p>
<ol>
<li>Edit src/soc/&lt;SoC Vendor&gt;/&lt;SoC Family&gt;/chip.c:
<ol type="A">
<li>
The domain operation table is typically placed in
src/soc/&lt;SoC Vendor&gt;/&lt;SoC Family&gt;/chip.c.
The table typically looks like the following:
<pre><code>static struct device_operations pci_domain_ops = {
.read_resources = pci_domain_read_resources,
.set_resources = pci_domain_set_resources,
.scan_bus = pci_domain_scan_bus,
.ops_pci_bus = pci_bus_default_ops,
};
</code></pre>
</li>
<li>
Create a .enable_dev entry in the chip operations table which points to a
routine which sets the domain table for the device with the DEVICE_PATH_DOMAIN.
<pre><code> if (dev->path.type == DEVICE_PATH_DOMAIN) {
dev->ops = &pci_domain_ops;
}
</code></pre>
</li>
<li>
During the BS_DEV_ENUMERATE state, ramstage now display the device IDs
for the PCI devices on the bus.
</li>
</ol>
</li>
<li>Set CONFIG_DEBUG_BOOT_STATE=y in the .config file</li>
<li>
Debug the result until the PCI vendor and device IDs are displayed
during the BS_DEV_ENUMERATE state.
</li>
</ol>
<h2><a name="DeviceDrivers">PCI Device Drivers</a></h2>
<p>
PCI device drivers consist of a ".c" file which contains a "pci_driver" data
structure at the end of the file with the attribute tag "__pci_driver". This
attribute tag places an entry into a link time table listing the various
coreboot device drivers.
</p>
<p>
Specify the following fields in the table:
</p>
<ol>
<li>.vendor - PCI vendor ID value of the device</li>
<li>.device - PCI device ID value of the device or<br>
.devices - Address of a zero terminated array of PCI device IDs
</li>
<li>.ops - Operations table for the device. This is the address
of a "static struct device_operations" data structure specifying
the routines to execute during the different states and sub-states
of ramstage's processing.
</li>
<li>Turn on the device in mainboard/&lt;Vendor&gt;/&lt;Board&gt;/devicetree.cb</li>
<li>
Debug until the device is on and properly configured in coreboot and
usable by the payload
</li>
</ol>
<h3><a name="SubsystemIds">Subsystem IDs</a></h3>
<p>
PCI subsystem IDs are assigned during the BS_DEV_ENABLE state. The device
driver may use the common mechanism to assign subsystem IDs by adding
the ".ops_pci" to the pci_driver data structure. This field points to
a "struct pci_operations" that specifies a routine to set the subsystem
IDs for the device. The routine might look something like this:
</p>
<pre><code>static void pci_set_subsystem(device_t dev, unsigned vendor, unsigned device)
{
if (!vendor || !device) {
vendor = pci_read_config32(dev, PCI_VENDOR_ID);
device = vendor >> 16;
}
printk(BIOS_SPEW,
"PCI: %02x:%02x:%d subsystem vendor: 0x%04x, device: 0x%04x\n",
0, PCI_SLOT(dev->path.pci.devfn), PCI_FUNC(dev->path.pci.devfn),
vendor & 0xffff, device);
pci_write_config32(dev, PCI_SUBSYSTEM_VENDOR_ID,
((device & 0xffff) << 16) | (vendor & 0xffff));
}
</code></pre>
<h2>Set up the <a name="MemoryMap">Memory Map</a></h2>
<p>
The memory map is built by the various PCI device drivers during the
BS_DEV_RESOURCES state of ramstage. The northcluster driver will typically
specify the DRAM resources while the other drivers will typically specify
the IO resources. These resources are hung off the device_t data structure by
src/device/device_util.c/<a target="_blank" href="http://review.coreboot.org/gitweb?p=coreboot.git;a=blob;f=src/device/device_util.c;hb=HEAD#l448">new_resource</a>.
</p>
<p>
During the BS_WRITE_TABLES state, coreboot collects these resources and
places them into a data structure identified by LB_MEM_TABLE.
</p>
<p>
Edit the device driver file:
</p>
<ol>
<li>
Implement a read_resources routine which calls macros defined in
src/include/device/<a target="_blank" href="http://review.coreboot.org/gitweb?p=coreboot.git;a=blob;f=src/include/device/device.h;hb=HEAD#l237">device.h</a>
like:
<ul>
<li>ram_resource</li>
<li>reserved_ram_resource</li>
<li>bad_ram_resource</li>
<li>uma_resource</li>
<li>mmio_resource</li>
</ul>
</li>
</ol>
<p>
Testing: Verify that the resources are properly displayed by coreboot during the BS_WRITE_TABLES state.
</p>
<hr>
<p>Modified: 18 February 2016</p>
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@ -94,6 +94,24 @@
</li>
</ol>
</li>
<li>
Implement the .init routine for the
<a target="_blank" href="SoC/soc.html#ChipOperations">chip operations</a>
structure which calls FSP SiliconInit
</li>
<li>
Start ramstage's
<a target="_blank" href="SoC/soc.html#DeviceTree">device tree processing</a>
to display the PCI vendor and device IDs
</li>
<li>
Disable the
<a target="_blank" href="Board/board.html#DisablePciDevices">PCI devices</a>
</li>
<li>
Implement the
<a target="_blank" href="SoC/soc.html#MemoryMap">memory map</a>
</li>
</ol>
@ -129,6 +147,31 @@
Disable: CONFIG_DISPLAY_MTRRS=y, MTRRs displayed after call to TempRamExit
</td>
</tr>
<tr>
<td>Memory Map</td>
<td>
Implement a device driver for the
<a target="_blank" href="SoC/soc.html#MemoryMap">north cluster</a>
</td>
<td>coreboot displays the memory map correctly during the BS_WRITE_TABLES state</td>
</tr>
<tr>
<td>PCI Device Support</td>
<td>Implement a PCI <a target="_blank" href="SoC/soc.html#DeviceDrivers">device driver</a></td>
<td>The device is detected by coreboot and usable by the payload</td>
</tr>
<tr>
<td>Ramstage state machine</td>
<td>
Implement the chip and domain operations to start the
<a target="_blank" href="SoC/soc.html#DeviceTree">device tree</a>
processing
</td>
<td>
During the BS_DEV_ENUMERATE state, ramstage now display the device IDs
for the PCI devices on the bus.
</td>
</tr>
<tr bgcolor="#c0ffc0">
@ -136,6 +179,19 @@
<th>Where</th>
<th>Testing</th>
</tr>
<tr>
<td>Device Tree</td>
<td>
<a target="_blank" href="SoC/soc.html#DeviceTree">List</a> PCI vendor and device IDs by starting
the device tree processing<br>
<a target="_blank" href="Board/board.html#DisablePciDevices">Disable</a> PCI devices<br>
Enable: Implement a PCI <a target="_blank" href="SoC/soc.html#DeviceDrivers">device driver</a>
<td>
List: BS_DEV_ENUMERATE state displays PCI vendor and device IDs<br>
Disable: BS_DEV_ENUMERATE state shows the devices as disabled<br>
Enable: BS_DEV_ENUMERATE state shows the device as on and the device works for the payload
</td>
</tr>
<tr>
<td>DRAM</td>
<td>
@ -208,11 +264,36 @@
</ul>
</td>
</tr>
<tr>
<td>SiliconInit</td>
<td>
Implement the .init routine for the
<a target="_blank" href="SoC/soc.html#ChipOperations">chip operations</a> structure
</td>
<td>During BS_DEV_INIT_CHIPS state, SiliconInit gets called and returns 0x00000000</td>
</tr>
<tr>
<td>FspNotify</td>
<td>
The code which calls FspNotify is located in
src/drivers/intel/fsp1_1/<a target="_blank" href="http://review.coreboot.org/gitweb?p=coreboot.git;a=blob;f=src/drivers/intel/fsp1_1/fsp_util.c;hb=HEAD#l182">fsp_util.c</a>.
The fsp_notify_boot_state_callback routine is called three times as specified
by the BOOT_STATE_INIT_ENTRY macros below the routine.
</td>
<td>
The FspNotify routines are called during:
<ul>
<li>BS_DEV_RESOURCES - on exit</li>
<li>BS_PAYLOAD_LOAD - on exit</li>
<li>BS_OS_RESUME - on entry (S3 resume)</li>
</ul>
</td>
</tr>
</table>
<hr>
<p>Modified: 31 January 2016</p>
<p>Modified: 15 February 2016</p>
</body>
</html>