1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Xilinx AXI Bridge for PCI Express Driver
4 *
5 * Copyright (C) 2016 Imagination Technologies
6 */
7
8 #include <common.h>
9 #include <dm.h>
10 #include <pci.h>
11
12 #include <asm/io.h>
13
14 /**
15 * struct xilinx_pcie - Xilinx PCIe controller state
16 * @cfg_base: The base address of memory mapped configuration space
17 */
18 struct xilinx_pcie {
19 void *cfg_base;
20 };
21
22 /* Register definitions */
23 #define XILINX_PCIE_REG_PSCR 0x144
24 #define XILINX_PCIE_REG_PSCR_LNKUP BIT(11)
25
26 /**
27 * pcie_xilinx_link_up() - Check whether the PCIe link is up
28 * @pcie: Pointer to the PCI controller state
29 *
30 * Checks whether the PCIe link for the given device is up or down.
31 *
32 * Return: true if the link is up, else false
33 */
pcie_xilinx_link_up(struct xilinx_pcie * pcie)34 static bool pcie_xilinx_link_up(struct xilinx_pcie *pcie)
35 {
36 uint32_t pscr = __raw_readl(pcie->cfg_base + XILINX_PCIE_REG_PSCR);
37
38 return pscr & XILINX_PCIE_REG_PSCR_LNKUP;
39 }
40
41 /**
42 * pcie_xilinx_config_address() - Calculate the address of a config access
43 * @udev: Pointer to the PCI bus
44 * @bdf: Identifies the PCIe device to access
45 * @offset: The offset into the device's configuration space
46 * @paddress: Pointer to the pointer to write the calculates address to
47 *
48 * Calculates the address that should be accessed to perform a PCIe
49 * configuration space access for a given device identified by the PCIe
50 * controller device @pcie and the bus, device & function numbers in @bdf. If
51 * access to the device is not valid then the function will return an error
52 * code. Otherwise the address to access will be written to the pointer pointed
53 * to by @paddress.
54 *
55 * Return: 0 on success, else -ENODEV
56 */
pcie_xilinx_config_address(struct udevice * udev,pci_dev_t bdf,uint offset,void ** paddress)57 static int pcie_xilinx_config_address(struct udevice *udev, pci_dev_t bdf,
58 uint offset, void **paddress)
59 {
60 struct xilinx_pcie *pcie = dev_get_priv(udev);
61 unsigned int bus = PCI_BUS(bdf);
62 unsigned int dev = PCI_DEV(bdf);
63 unsigned int func = PCI_FUNC(bdf);
64 void *addr;
65
66 if ((bus > 0) && !pcie_xilinx_link_up(pcie))
67 return -ENODEV;
68
69 /*
70 * Busses 0 (host-PCIe bridge) & 1 (its immediate child) are
71 * limited to a single device each.
72 */
73 if ((bus < 2) && (dev > 0))
74 return -ENODEV;
75
76 addr = pcie->cfg_base;
77 addr += bus << 20;
78 addr += dev << 15;
79 addr += func << 12;
80 addr += offset;
81 *paddress = addr;
82
83 return 0;
84 }
85
86 /**
87 * pcie_xilinx_read_config() - Read from configuration space
88 * @bus: Pointer to the PCI bus
89 * @bdf: Identifies the PCIe device to access
90 * @offset: The offset into the device's configuration space
91 * @valuep: A pointer at which to store the read value
92 * @size: Indicates the size of access to perform
93 *
94 * Read a value of size @size from offset @offset within the configuration
95 * space of the device identified by the bus, device & function numbers in @bdf
96 * on the PCI bus @bus.
97 *
98 * Return: 0 on success, else -ENODEV or -EINVAL
99 */
pcie_xilinx_read_config(struct udevice * bus,pci_dev_t bdf,uint offset,ulong * valuep,enum pci_size_t size)100 static int pcie_xilinx_read_config(struct udevice *bus, pci_dev_t bdf,
101 uint offset, ulong *valuep,
102 enum pci_size_t size)
103 {
104 return pci_generic_mmap_read_config(bus, pcie_xilinx_config_address,
105 bdf, offset, valuep, size);
106 }
107
108 /**
109 * pcie_xilinx_write_config() - Write to configuration space
110 * @bus: Pointer to the PCI bus
111 * @bdf: Identifies the PCIe device to access
112 * @offset: The offset into the device's configuration space
113 * @value: The value to write
114 * @size: Indicates the size of access to perform
115 *
116 * Write the value @value of size @size from offset @offset within the
117 * configuration space of the device identified by the bus, device & function
118 * numbers in @bdf on the PCI bus @bus.
119 *
120 * Return: 0 on success, else -ENODEV or -EINVAL
121 */
pcie_xilinx_write_config(struct udevice * bus,pci_dev_t bdf,uint offset,ulong value,enum pci_size_t size)122 static int pcie_xilinx_write_config(struct udevice *bus, pci_dev_t bdf,
123 uint offset, ulong value,
124 enum pci_size_t size)
125 {
126 return pci_generic_mmap_write_config(bus, pcie_xilinx_config_address,
127 bdf, offset, value, size);
128 }
129
130 /**
131 * pcie_xilinx_ofdata_to_platdata() - Translate from DT to device state
132 * @dev: A pointer to the device being operated on
133 *
134 * Translate relevant data from the device tree pertaining to device @dev into
135 * state that the driver will later make use of. This state is stored in the
136 * device's private data structure.
137 *
138 * Return: 0 on success, else -EINVAL
139 */
pcie_xilinx_ofdata_to_platdata(struct udevice * dev)140 static int pcie_xilinx_ofdata_to_platdata(struct udevice *dev)
141 {
142 struct xilinx_pcie *pcie = dev_get_priv(dev);
143 struct fdt_resource reg_res;
144 DECLARE_GLOBAL_DATA_PTR;
145 int err;
146
147 err = fdt_get_resource(gd->fdt_blob, dev_of_offset(dev), "reg",
148 0, ®_res);
149 if (err < 0) {
150 pr_err("\"reg\" resource not found\n");
151 return err;
152 }
153
154 pcie->cfg_base = map_physmem(reg_res.start,
155 fdt_resource_size(®_res),
156 MAP_NOCACHE);
157
158 return 0;
159 }
160
161 static const struct dm_pci_ops pcie_xilinx_ops = {
162 .read_config = pcie_xilinx_read_config,
163 .write_config = pcie_xilinx_write_config,
164 };
165
166 static const struct udevice_id pcie_xilinx_ids[] = {
167 { .compatible = "xlnx,axi-pcie-host-1.00.a" },
168 { }
169 };
170
171 U_BOOT_DRIVER(pcie_xilinx) = {
172 .name = "pcie_xilinx",
173 .id = UCLASS_PCI,
174 .of_match = pcie_xilinx_ids,
175 .ops = &pcie_xilinx_ops,
176 .ofdata_to_platdata = pcie_xilinx_ofdata_to_platdata,
177 .priv_auto_alloc_size = sizeof(struct xilinx_pcie),
178 };
179