diff options
Diffstat (limited to 'src/soc/intel/apollolake/lpc.c')
-rw-r--r-- | src/soc/intel/apollolake/lpc.c | 72 |
1 files changed, 71 insertions, 1 deletions
diff --git a/src/soc/intel/apollolake/lpc.c b/src/soc/intel/apollolake/lpc.c index 10677df503..5b552d8491 100644 --- a/src/soc/intel/apollolake/lpc.c +++ b/src/soc/intel/apollolake/lpc.c @@ -19,8 +19,27 @@ #include <device/pci.h> #include <device/pci_ids.h> #include <soc/acpi.h> +#include <soc/lpc.h> #include <soc/pci_ids.h> +/* + * SCOPE: + * The purpose of this driver is to eliminate manual resource allocation for + * devices under the LPC bridge. + * + * BACKGROUND: + * The resource allocator reserves IO and memory resources to devices on the + * LPC bus, but it is up to the hardware driver to make sure that those + * resources are decoded to the LPC bus. This is what this driver does. + * + * THEORY OF OPERATION: + * The .scan_bus member of the driver's ops will scan the static device tree + * (devicetree.cb) and invoke drivers of devices on the LPC bus. This creates + * a list of child devices, along with their resources. set_child_resources() + * parses that list and looks for resources needed by the child devices. It + * opens up IO and memory windows as needed. + */ + static void soc_lpc_add_io_resources(device_t dev) { struct resource *res; @@ -41,12 +60,63 @@ static void soc_lpc_read_resources(device_t dev) soc_lpc_add_io_resources(dev); } +static void set_child_resources(struct device *dev); + +static void loop_resources(struct device *dev) +{ + struct resource *res; + + for (res = dev->resource_list; res; res = res->next) { + + if (res->flags & IORESOURCE_IO) { + lpc_open_pmio_window(res->base, res->size); + } + + if (res->flags & IORESOURCE_MEM) { + /* Check if this is already decoded. */ + if (lpc_fits_fixed_mmio_window(res->base, res->size)) + continue; + + lpc_open_mmio_window(res->base, res->size); + } + + } + set_child_resources(dev); +} + +/* + * Loop through all the child devices' resources, and open up windows to the + * LPC bus, as appropriate. + */ +static void set_child_resources(struct device *dev) +{ + struct bus *link; + struct device *child; + + for (link = dev->link_list; link; link = link->next) { + for (child = link->children; child; child = child->sibling) { + loop_resources(child); + } + } +} + +static void set_resources(device_t dev) +{ + pci_dev_set_resources(dev); + + /* Close all previously opened windows and allocate from scratch. */ + lpc_close_pmio_windows(); + /* Now open up windows to devices which have declared resources. */ + set_child_resources(dev); +} + static struct device_operations device_ops = { .read_resources = &soc_lpc_read_resources, - .set_resources = &pci_dev_set_resources, + .set_resources = set_resources, .enable_resources = &pci_dev_enable_resources, .write_acpi_tables = southbridge_write_acpi_tables, .acpi_inject_dsdt_generator = southbridge_inject_dsdt, + .scan_bus = scan_lpc_bus, }; static const struct pci_driver soc_lpc __pci_driver = { |