1 The U-Boot Driver Model Project
2 ===============================
6 Pavel Herrmann <morpheus.ibis@gmail.com>
12 U-Boot already supports multiple PCI busses, stored in a linked-list of
13 pci_controller structures. This structure contains generic driver data, bus
14 interface operations and private data for the driver.
16 Bus interface operations for PCI are (names are self-explanatory):
25 Each driver has to implement dword operations, and either implement word and
26 byte operations, or use shared $operation_config_$type_via_dword (eg.
27 read_config_byte_via_dword and similar) function. These functions are used
28 for config space I/O (read_config_dword and similar functions of the PCI
29 subsystem), which is used to configure the connected devices for standard MMIO
30 operations. All data transfers by respective device drivers are then done by
33 Each driver also defines a separate init function, which has unique symbol
34 name, and thus more drivers can be compiled in without colliding. This init
35 function is typically called from pci_init_board(), different for each
38 Some boards also define a function called fixup_irq, which gets called after
39 scanning the PCI bus for devices, and should dismiss any interrupts.
41 Several drivers are also located in arch/ and should be moved to drivers/pci.
46 The pci_controller structure needs to be broken down to fit the new driver
47 model. Due to a large number of members, this will be done through three
48 distinct accessors, one for memory regions, one for config table and one for
49 everything else. That will make the pci_ops structure look like this:
52 int (*read_byte)(struct instance *bus, pci_dev_t *dev, int addr,
54 int (*read_word)(struct instance *bus, pci_dev_t *dev, int addr,
56 int (*read_dword)(struct instance *bus, pci_dev_t *dev, int addr,
58 int (*write_byte)(struct instance *bus, pci_dev_t *dev, int addr,
60 int (*write_byte)(struct instance *bus, pci_dev_t *dev, int addr,
62 int (*write_dword)(struct instance *bus, pci_dev_t *dev, int addr,
64 void (*fixup_irq)(struct instance *bus, pci_dev_t *dev);
65 struct pci_region* (*get_region)(struct instance *, uint num);
66 struct pci_config_table* (*get_cfg_table)(struct instance *bus);
67 uint (*get_option)(struct instance * bus, enum pci_option_code op);
70 enum pci_option_code {
73 PCI_OPT_INDIRECT_TYPE,
76 PCI_OPT_AUTO_PREFETCH,
82 The return value for get_option will be an unsigned integer value for any
83 option code. If the option currently is a pointer to pci_region, it will
84 return an index for get_region function. Special case has to be made for
85 PCI_OPT_CFG_ADDR, which should be interpreted as a pointer, but it is only
86 used for equality in find_hose_by_cfg_addr, and thus can be returned as an
87 uint. Other function using cfg_addr value are read/write functions for
88 specific drivers (especially ops for indirect bridges), and thus have access
89 to private_data of the driver instance.
91 The config table accessor will return a pointer to a NULL-terminated array of
92 pci_config_table, which is supplied by the board in platform_data, or NULL if
93 the board didn't specify one. This table is used to override PnP
94 auto-initialization, or to specific initialization functions for non-PNP
97 Transparent PCI-PCI bridges will get their own driver, and will forward all
98 operations to operations of their parent bus. This however makes it
99 impossible to use instances to identify devices, as not all devices will be
100 directly visible to the respective bus driver.
102 Init functions of controller drivers will be moved to their respective
103 probe() functions, in accordance to the driver model.
105 The PCI core will handle all mapping functions currently found in pci.c, as
106 well as proxy functions for read/write operations of the drivers. The PCI
107 core will also handle bus scanning and device configuration.
109 The PnP helper functions currently in pci_auto.c will also be a part of PCI
110 core, but they will be exposed only to PCI controller drivers, not to other
113 The PCI API for device drivers will remain largely unchanged, most drivers
114 will require no changes at all, and all modifications will be limited to
115 changing the pci_controlle into instance*.
117 III) Analysis of in-tree drivers
118 --------------------------------
120 A) drivers in drivers/pci/
121 --------------------------
125 Shared driver for indirect PCI bridges, several CONFIG macros - will
126 require significant cleanup.
130 Shared init function for SH4 drivers, uses dword for read/write ops.
134 Standard driver, uses SH4 shared init.
138 Standard driver, uses SH4 shared init.
142 Standard driver, uses dword for read/write ops.
146 Driver for PCI and PCI-e, uses indirect functions.
150 Standard driver, uses indirect functions, has separate scan/setup
158 Standard driver, specifies all read/write functions separately.
160 m68k/cpu/mcf5445x/pci.c
161 -----------------------
162 Standard driver, specifies all read/write functions separately.
164 m68k/cpu/mcf547x_8x/pci.c
165 -------------------------
166 Standard driver, specifies all read/write functions separately.
168 powerpc/cpu/mpc824x/pci.c
169 -------------------------
170 Standard driver, uses indirect functions, does not setup HW.
172 powerpc/cpu/mpc8260/pci.c
173 -------------------------
174 Standard driver, uses indirect functions.
176 powerpc/cpu/ppc4xx/4xx_pci.c
177 ----------------------------
178 Standard driver, uses indirect functions.
180 powerpc/cpu/ppc4xx/4xx_pcie.c
181 -----------------------------
182 PCI-e driver, specifies all read/write functions separately.
184 powerpc/cpu/mpc83xx/pci.c
185 -------------------------
186 Standard driver, uses indirect functions.
188 powerpc/cpu/mpc83xx/pcie.c
189 --------------------------
190 PCI-e driver, specifies all read/write functions separately.
192 powerpc/cpu/mpc5xxx/pci_mpc5200.c
193 ---------------------------------
194 Standard driver, uses dword for read/write ops.
196 powerpc/cpu/mpc512x/pci.c
197 -------------------------
198 Standard driver, uses indirect functions.
200 powerpc/cpu/mpc85xx/pci.c
201 -------------------------
202 Standard driver, uses indirect functions, has two busses.
209 Standard driver, uses indirect functions.
213 Standard driver, specifies all read/write functions separately.
217 Standard driver, uses dword for read/write ops, has two busses.
221 Standard driver, uses dword for read/write ops, has two busses.
225 Standard driver, uses dword for read/write ops.
229 Standard driver, uses dword for read/write ops.
233 Standard driver, uses indirect functions.
235 Marvell/db64360/pci.c
236 ---------------------
237 Standard driver, uses dword for read/write ops, has two busses.
239 Marvell/db64460/pci.c
240 ---------------------
241 Standard driver, uses dword for read/write ops, has two busses.
245 Standard driver, uses dword for read/write ops, has two busses.
247 armltd/integrator/pci.c
248 -----------------------
249 Standard driver, specifies all read/write functions separately.
251 All drivers will be moved to drivers/pci. Several drivers seem
252 similar/identical, especially those located under board, and may be merged