PCI_X_CMD_MAX_READ
cmd = PCI_X_CMD_MAX_SPLIT | PCI_X_CMD_MAX_READ
pcix_cmd &= ~PCI_X_CMD_MAX_READ;
pcix_cmd &= ~(PCI_X_CMD_MAX_SPLIT | PCI_X_CMD_MAX_READ);
return 512 << FIELD_GET(PCI_X_CMD_MAX_READ, cmd);
o = FIELD_GET(PCI_X_CMD_MAX_READ, cmd);
FIELD_MODIFY(PCI_X_CMD_MAX_READ, &cmd, v);