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[PATCH 2/8] ppc/pnv: Wire up pca9552 GPIO pins for PCIe hotplug power co
From: |
Glenn Miles |
Subject: |
[PATCH 2/8] ppc/pnv: Wire up pca9552 GPIO pins for PCIe hotplug power control |
Date: |
Fri, 10 Nov 2023 11:22:42 -0600 |
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 <milesg@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
- [PATCH 0/8] Add powernv10 I2C devices and tests, Glenn Miles, 2023/11/10
- [PATCH 1/8] ppc/pnv: Add pca9552 to powernv10 for PCIe hotplug power control, Glenn Miles, 2023/11/10
- [PATCH 2/8] ppc/pnv: Wire up pca9552 GPIO pins for PCIe hotplug power control,
Glenn Miles <=
- [PATCH 5/8] ppc/pnv: Use resettable interface to reset child I2C buses, Glenn Miles, 2023/11/10
- [PATCH 3/8] ppc/pnv: PNV I2C engines assigned incorrect XSCOM addresses, Glenn Miles, 2023/11/10
- [PATCH 4/8] ppc/pnv: Fix PNV I2C invalid status after reset, Glenn Miles, 2023/11/10
- [PATCH 6/8] misc: Add a pca9554 GPIO device model, Glenn Miles, 2023/11/10
- [PATCH 7/8] ppc/pnv: Add a pca9554 I2C device to powernv10, Glenn Miles, 2023/11/10
- [PATCH 8/8] ppc/pnv: Test pnv i2c master and connected devices, Glenn Miles, 2023/11/10
- Re: [PATCH 0/8] Add powernv10 I2C devices and tests, Miles Glenn, 2023/11/10