drivers/pci/vc.c

1 // SPDX-License-Identifier: GPL-2.0
19  * pci_vc_save_restore_dwords - Save or restore a series of dwords
22  * @buf: buffer to save to or restore from
40  * pci_vc_load_arb_table - load and wait for VC arbitration table
63  * pci_vc_load_port_arb_table - Load and wait for VC port arbitration table
66  * @res: VC resource number, ie. VCn (0-7)
91  * pci_vc_enable - Enable virtual channel
94  * @res: VC res number, ie. VCn (0-7)
96  * A VC is enabled by setting the enable bit in matching resource control
98  * end of the link.  To keep this simple we enable from the downstream device.
101  * get the correct resource, disable and enable on both ends.
109 	/* Enable VCs from the downstream device */  in pci_vc_enable()
121 	/* If there is no opposite end of the link, skip to enable */  in pci_vc_enable()
123 	    pci_is_root_bus(dev->bus))  in pci_vc_enable()
124 		goto enable;  in pci_vc_enable()
126 	pos2 = pci_find_ext_capability(dev->bus->self, PCI_EXT_CAP_ID_VC);  in pci_vc_enable()
128 		goto enable;  in pci_vc_enable()
130 	pci_read_config_dword(dev->bus->self, pos2 + PCI_VC_PORT_CAP1, &cap1);  in pci_vc_enable()
139 		pci_read_config_dword(dev->bus->self, ctrl_pos2, &ctrl2);  in pci_vc_enable()
141 			link = dev->bus->self;  in pci_vc_enable()
147 		goto enable;  in pci_vc_enable()
155 	/* Enable on both ends */  in pci_vc_enable()
158 enable:  in pci_vc_enable()
171  * pci_vc_do_save_buffer - Size, save, or restore VC state
174  * @save_state: buffer for save/restore
175  * @save: if provided a buffer, this indicates what to do with it
179  * guarantee ordering matches in the buffer.  When called with NULL
180  * @save_state, return the size of the necessary save buffer.  When called
181  * with a non-NULL @save_state, @save determines whether we save to the
182  * buffer or restore from it.
191 	u8 *buf = save_state ? (u8 *)save_state->cap.data : NULL;  in pci_vc_do_save_buffer()
193 	/* Sanity check buffer size for save/restore */  in pci_vc_do_save_buffer()
194 	if (buf && save_state->cap.size !=  in pci_vc_do_save_buffer()
196 		pci_err(dev, "VC save buffer size does not match @0x%x\n", pos);  in pci_vc_do_save_buffer()
197 		return -ENOMEM;  in pci_vc_do_save_buffer()
256 				 * re-load the VC Arbitration Table.  in pci_vc_do_save_buffer()
317 				 * Preserve enable bit, restore the rest.  in pci_vc_do_save_buffer()
326 				/* Re-enable if needed */  in pci_vc_do_save_buffer()
346  * pci_save_vc_state - Save VC state to pre-allocate save buffer
350  * save it to the pre-allocated save buffer.
366 			pci_err(dev, "%s buffer not found in %s\n",  in pci_save_vc_state()
368 			return -ENOMEM;  in pci_save_vc_state()
383  * pci_restore_vc_state - Restore VC state from save buffer
387  * restore it from the previously saved buffer.
407  * pci_allocate_vc_save_buffers - Allocate save buffers for VC caps
411  * it, and allocate a buffer for save/restore.
425 			pci_err(dev, "unable to preallocate %s save buffer\n",  in pci_allocate_vc_save_buffers()