There are x86 platforms where the IRQ configuration register for PCIe
is not pre-populated and the OS needs to assign a number dynamically
by writing to the register.
In order to allocate interrupts we have to know which ones have been
hard-coded in device tree. We accomplish this by collecting these
values through the IRQ_CONNECT() macro and placing them in a dedicated
linker section (in ROM).
The full set of allocated interrupts are managed through a bitmap, and
the pre-allocated values (from the linker section) are inserted into
this upon initial runtime access.
This patch introduces a new pcie_alloc_irq() API that drivers can use
to allocate interrupt line numbers. The two in-tree drivers that were
using this API (I2C and UART) are converted to use the new API.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
9e4dfd8f4e