diff options
| -rw-r--r-- | hw/npu2-opencapi.c | 46 |
1 files changed, 40 insertions, 6 deletions
diff --git a/hw/npu2-opencapi.c b/hw/npu2-opencapi.c index a54ef63..9ddb603 100644 --- a/hw/npu2-opencapi.c +++ b/hw/npu2-opencapi.c @@ -919,19 +919,53 @@ err: static void deassert_adapter_reset(struct npu2_dev *dev) { uint8_t pin, data; - int rc; + int rc, rc2; pin = get_reset_pin(dev); + /* + * All we need to do here is deassert the reset signal by + * setting the reset pin to high. However, we cannot leave the + * pin in output mode, as it can cause troubles with the + * opencapi adapter: when the slot is powered off (on a reboot + * for example), if the i2c controller is actively setting the + * reset signal to high, it maintains voltage on part of the + * fpga and can leak current. It can lead the fpga to be in an + * unspecified state and potentially cause damage. + * + * The circumvention is to set the pin back to input + * mode. There are pullup resistors on the planar on all + * platforms to make sure the signal will "naturally" be high, + * without the i2c controller actively setting it, so we won't + * have problems when the slot is powered off. And it takes + * the adapter out of reset. + * + * To summarize: + * 1. set the pin to input mode. That is enough to raise the + * signal + * 2. set the value of the pin to high. The pin is input mode, + * so it won't really do anything. But it's more coherent + * and avoids bad surprises on the next call to + * assert_adapter_reset() + */ lock(&dev->npu->i2c_lock); - dev->npu->i2c_pin_wr_state |= pin; - data = dev->npu->i2c_pin_wr_state; + dev->npu->i2c_pin_mode |= pin; + data = dev->npu->i2c_pin_mode; rc = i2c_request_send(dev->npu->i2c_port_id_ocapi, - platform.ocapi->i2c_reset_addr, SMBUS_WRITE, - 0x1, 1, - &data, sizeof(data), 120); + platform.ocapi->i2c_reset_addr, SMBUS_WRITE, + 0x3, 1, + &data, sizeof(data), 120); + + dev->npu->i2c_pin_wr_state |= pin; + data = dev->npu->i2c_pin_wr_state; + rc2 = i2c_request_send(dev->npu->i2c_port_id_ocapi, + platform.ocapi->i2c_reset_addr, SMBUS_WRITE, + 0x1, 1, + &data, sizeof(data), 120); unlock(&dev->npu->i2c_lock); + if (!rc) + rc = rc2; if (rc) { /** * @fwts-label OCAPIDeviceResetFailed |