For power10, a pca9552 device is used for PCIe slot hotplug power control by the Power Hypervisor code. The code expects that some time after it enables power to a PCIe slot by asserting one of the pca9552 GPIO pins 0-4, it should see a "power good" signal asserted on one of pca9552 GPIO pins 5-9.
To simulate this behavior, we simply connect the GPIO outputs for pins 0-4 to the GPIO inputs for pins 5-9. Each PCIe slot is assigned 3 GPIO pins on the pca9552 device, for control of up to 5 PCIe slots. The per-slot signal names are: SLOTx_EN.......PHYP uses this as an output to enable slot power. We connect this to the SLOTx_PG pin to simulate a PGOOD signal. SLOTx_PG.......PHYP uses this as in input to detect PGOOD for the slot. For our purposes we just connect this to the SLOTx_EN output. SLOTx_Control..PHYP uses this as an output to prevent a race condition in the real hotplug circuitry, but we can ignore this output for simulation. Signed-off-by: Glenn Miles <mil...@linux.vnet.ibm.com> --- hw/ppc/pnv.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) diff --git a/hw/ppc/pnv.c b/hw/ppc/pnv.c index 7afaf1008f..0b24d7d8ed 100644 --- a/hw/ppc/pnv.c +++ b/hw/ppc/pnv.c @@ -1882,7 +1882,24 @@ static void pnv_chip_power10_realize(DeviceState *dev, Error **errp) * Add a PCA9552 I2C device for PCIe hotplug control * to engine 2, bus 1, address 0x63 */ - i2c_slave_create_simple(chip10->i2c[2].busses[1], "pca9552", 0x63); + I2CSlave* hotplug = i2c_slave_create_simple(chip10->i2c[2].busses[1], + "pca9552", 0x63); + + /* + * Connect PCA9552 GPIO pins 0-4 (SLOTx_EN) outputs to GPIO pins 5-9 + * (SLOTx_PG) inputs in order to fake the pgood state of PCIe slots after + * hypervisor code sets a SLOTx_EN pin high. + */ + qdev_connect_gpio_out(DEVICE(hotplug), 0, + qdev_get_gpio_in(DEVICE(hotplug), 5)); + qdev_connect_gpio_out(DEVICE(hotplug), 1, + qdev_get_gpio_in(DEVICE(hotplug), 6)); + qdev_connect_gpio_out(DEVICE(hotplug), 2, + qdev_get_gpio_in(DEVICE(hotplug), 7)); + qdev_connect_gpio_out(DEVICE(hotplug), 3, + qdev_get_gpio_in(DEVICE(hotplug), 8)); + qdev_connect_gpio_out(DEVICE(hotplug), 4, + qdev_get_gpio_in(DEVICE(hotplug), 9)); } -- 2.31.1