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diff --git a/Documentation/Intel/SoC/soc.html b/Documentation/Intel/SoC/soc.html index b5daac8fb5..146e768183 100644 --- a/Documentation/Intel/SoC/soc.html +++ b/Documentation/Intel/SoC/soc.html @@ -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/<Vendor>/<Board>/devicetree.cb file drives the + execution during ramstage. This file is processed by the util/sconfig utility + to generate build/mainboard/<Vendor>/<Board>/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/<SoC Vendor>/<SoC Family>/chip.c: + <ol type="A"> + <li> + This chip's operation table has the name + soc_<SoC Vendor>_<SoC Family>_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/<SoC Vendor>/<SoC Family>/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/<SoC Vendor>/<SoC Family>/chip.c: + <ol type="A"> + <li> + The domain operation table is typically placed in + src/soc/<SoC Vendor>/<SoC Family>/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/<Vendor>/<Board>/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> </body> </html>
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