1/*
 2 * SDK7786 FPGA PCIe mux handling
 3 *
 4 * Copyright (C) 2010  Paul Mundt
 5 *
 6 * This file is subject to the terms and conditions of the GNU General Public
 7 * License.  See the file "COPYING" in the main directory of this archive
 8 * for more details.
 9 */
10#define pr_fmt(fmt) "PCI: " fmt
11
12#include <linux/init.h>
13#include <linux/kernel.h>
14#include <linux/pci.h>
15#include <mach/fpga.h>
16
17/*
18 * The SDK7786 FPGA supports mangling of most of the slots in some way or
19 * another. Slots 3/4 are special in that only one can be supported at a
20 * time, and both appear on port 3 to the PCI bus scan. Enabling slot 4
21 * (the horizontal edge connector) will disable slot 3 entirely.
22 *
23 * Misconfigurations can be detected through the FPGA via the slot
24 * resistors to determine card presence. Hotplug remains unsupported.
25 */
26static unsigned int slot4en __initdata;
27
28char *__init pcibios_setup(char *str)
29{
30	if (strcmp(str, "slot4en") == 0) {
31		slot4en = 1;
32		return NULL;
33	}
34
35	return str;
36}
37
38static int __init sdk7786_pci_init(void)
39{
40	u16 data = fpga_read_reg(PCIECR);
41
42	/*
43	 * Enable slot #4 if it's been specified on the command line.
44	 *
45	 * Optionally reroute if slot #4 has a card present while slot #3
46	 * does not, regardless of command line value.
47	 *
48	 * Card presence is logically inverted.
49	 */
50	slot4en ?: (!(data & PCIECR_PRST4) && (data & PCIECR_PRST3));
51	if (slot4en) {
52		pr_info("Activating PCIe slot#4 (disabling slot#3)\n");
53
54		data &= ~PCIECR_PCIEMUX1;
55		fpga_write_reg(data, PCIECR);
56
57		/* Warn about forced rerouting if slot#3 is occupied */
58		if ((data & PCIECR_PRST3) == 0) {
59			pr_warning("Unreachable card detected in slot#3\n");
60			return -EBUSY;
61		}
62	} else
63		pr_info("PCIe slot#4 disabled\n");
64
65	return 0;
66}
67postcore_initcall(sdk7786_pci_init);

 1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * SDK7786 FPGA PCIe mux handling
 4 *
 5 * Copyright (C) 2010  Paul Mundt
 
 
 
 
 6 */
 7#define pr_fmt(fmt) "PCI: " fmt
 8
 9#include <linux/init.h>
10#include <linux/kernel.h>
11#include <linux/pci.h>
12#include <mach/fpga.h>
13
14/*
15 * The SDK7786 FPGA supports mangling of most of the slots in some way or
16 * another. Slots 3/4 are special in that only one can be supported at a
17 * time, and both appear on port 3 to the PCI bus scan. Enabling slot 4
18 * (the horizontal edge connector) will disable slot 3 entirely.
19 *
20 * Misconfigurations can be detected through the FPGA via the slot
21 * resistors to determine card presence. Hotplug remains unsupported.
22 */
23static unsigned int slot4en __initdata;
24
25char *__init pcibios_setup(char *str)
26{
27	if (strcmp(str, "slot4en") == 0) {
28		slot4en = 1;
29		return NULL;
30	}
31
32	return str;
33}
34
35static int __init sdk7786_pci_init(void)
36{
37	u16 data = fpga_read_reg(PCIECR);
38
39	/*
40	 * Enable slot #4 if it's been specified on the command line.
41	 *
42	 * Optionally reroute if slot #4 has a card present while slot #3
43	 * does not, regardless of command line value.
44	 *
45	 * Card presence is logically inverted.
46	 */
47	slot4en ?: (!(data & PCIECR_PRST4) && (data & PCIECR_PRST3));
48	if (slot4en) {
49		pr_info("Activating PCIe slot#4 (disabling slot#3)\n");
50
51		data &= ~PCIECR_PCIEMUX1;
52		fpga_write_reg(data, PCIECR);
53
54		/* Warn about forced rerouting if slot#3 is occupied */
55		if ((data & PCIECR_PRST3) == 0) {
56			pr_warn("Unreachable card detected in slot#3\n");
57			return -EBUSY;
58		}
59	} else
60		pr_info("PCIe slot#4 disabled\n");
61
62	return 0;
63}
64postcore_initcall(sdk7786_pci_init);