hw/intc/arm_gic: Document QEMU interface

The GICv2's QEMU interface (sysbus MMIO regions, IRQs,
etc) is now quite complicated with the addition of the
virtualization extensions. Add a comment in the header
file which documents it.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Luc Michel <luc.michel@greensocs.com>
Message-id: 20180823103818.31189-1-peter.maydell@linaro.org
This commit is contained in:
Peter Maydell 2018-09-25 14:02:32 +01:00
parent 9f4d2a1316
commit 48314d8316

View file

@ -18,6 +18,49 @@
* with this program; if not, see <http://www.gnu.org/licenses/>.
*/
/*
* QEMU interface:
* + QOM property "num-cpu": number of CPUs to support
* + QOM property "num-irq": number of IRQs (including both SPIs and PPIs)
* + QOM property "revision": GIC version (1 or 2), or 0 for the 11MPCore GIC
* + QOM property "has-security-extensions": set true if the GIC should
* implement the security extensions
* + QOM property "has-virtualization-extensions": set true if the GIC should
* implement the virtualization extensions
* + unnamed GPIO inputs: (where P is number of SPIs, i.e. num-irq - 32)
* [0..P-1] SPIs
* [P..P+31] PPIs for CPU 0
* [P+32..P+63] PPIs for CPU 1
* ...
* + sysbus IRQs: (in order; number will vary depending on number of cores)
* - IRQ for CPU 0
* - IRQ for CPU 1
* ...
* - FIQ for CPU 0
* - FIQ for CPU 1
* ...
* - VIRQ for CPU 0 (exists even if virt extensions not present)
* - VIRQ for CPU 1 (exists even if virt extensions not present)
* ...
* - VFIQ for CPU 0 (exists even if virt extensions not present)
* - VFIQ for CPU 1 (exists even if virt extensions not present)
* ...
* - maintenance IRQ for CPU i/f 0 (only if virt extensions present)
* - maintenance IRQ for CPU i/f 1 (only if virt extensions present)
* + sysbus MMIO regions: (in order; numbers will vary depending on
* whether virtualization extensions are present and on number of cores)
* - distributor registers (GICD*)
* - CPU interface for the accessing core (GICC*)
* - virtual interface control registers (GICH*) (only if virt extns present)
* - virtual CPU interface for the accessing core (GICV*) (only if virt)
* - CPU 0 CPU interface registers
* - CPU 1 CPU interface registers
* ...
* - CPU 0 virtual interface control registers (only if virt extns present)
* - CPU 1 virtual interface control registers (only if virt extns present)
* ...
*/
#ifndef HW_ARM_GIC_H
#define HW_ARM_GIC_H