upstream u-boot with additional patches for our devices/boards:
https://lists.denx.de/pipermail/u-boot/2017-March/282789.html (AXP crashes) ;
Gbit ethernet patch for some LIME2 revisions ;
with SPI flash support
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
257 lines
8.7 KiB
257 lines
8.7 KiB
The U-Boot Driver Model Project
|
|
===============================
|
|
PCI subsystem analysis
|
|
======================
|
|
|
|
Pavel Herrmann <morpheus.ibis@gmail.com>
|
|
2012-03-17
|
|
|
|
I) Overview
|
|
-----------
|
|
|
|
U-Boot already supports multiple PCI busses, stored in a linked-list of
|
|
pci_controller structures. This structure contains generic driver data, bus
|
|
interface operations and private data for the driver.
|
|
|
|
Bus interface operations for PCI are (names are self-explanatory):
|
|
|
|
read_byte()
|
|
read_word()
|
|
read_dword()
|
|
write_byte()
|
|
write_word()
|
|
write_dword()
|
|
|
|
Each driver has to implement dword operations, and either implement word and
|
|
byte operations, or use shared $operation_config_$type_via_dword (eg.
|
|
read_config_byte_via_dword and similar) function. These functions are used
|
|
for config space I/O (read_config_dword and similar functions of the PCI
|
|
subsystem), which is used to configure the connected devices for standard MMIO
|
|
operations. All data transfers by respective device drivers are then done by
|
|
MMIO
|
|
|
|
Each driver also defines a separate init function, which has unique symbol
|
|
name, and thus more drivers can be compiled in without colliding. This init
|
|
function is typically called from pci_init_board(), different for each
|
|
particular board.
|
|
|
|
Some boards also define a function called fixup_irq, which gets called after
|
|
scanning the PCI bus for devices, and should dismiss any interrupts.
|
|
|
|
Several drivers are also located in arch/ and should be moved to drivers/pci.
|
|
|
|
II) Approach
|
|
------------
|
|
|
|
The pci_controller structure needs to be broken down to fit the new driver
|
|
model. Due to a large number of members, this will be done through three
|
|
distinct accessors, one for memory regions, one for config table and one for
|
|
everything else. That will make the pci_ops structure look like this:
|
|
|
|
struct pci_ops {
|
|
int (*read_byte)(struct instance *bus, pci_dev_t *dev, int addr,
|
|
u8 *buf);
|
|
int (*read_word)(struct instance *bus, pci_dev_t *dev, int addr,
|
|
u16 *buf);
|
|
int (*read_dword)(struct instance *bus, pci_dev_t *dev, int addr,
|
|
u32 *buf);
|
|
int (*write_byte)(struct instance *bus, pci_dev_t *dev, int addr,
|
|
u8 val);
|
|
int (*write_byte)(struct instance *bus, pci_dev_t *dev, int addr,
|
|
u8 val);
|
|
int (*write_dword)(struct instance *bus, pci_dev_t *dev, int addr,
|
|
u32 val);
|
|
void (*fixup_irq)(struct instance *bus, pci_dev_t *dev);
|
|
struct pci_region* (*get_region)(struct instance *, uint num);
|
|
struct pci_config_table* (*get_cfg_table)(struct instance *bus);
|
|
uint (*get_option)(struct instance * bus, enum pci_option_code op);
|
|
}
|
|
|
|
enum pci_option_code {
|
|
PCI_OPT_BUS_NUMBER=0,
|
|
PCI_OPT_REGION_COUNT,
|
|
PCI_OPT_INDIRECT_TYPE,
|
|
PCI_OPT_AUTO_MEM,
|
|
PCI_OPT_AUTO_IO,
|
|
PCI_OPT_AUTO_PREFETCH,
|
|
PCI_OPT_AUTO_FB,
|
|
PCI_OPT_CURRENT_BUS,
|
|
PCI_OPT_CFG_ADDR,
|
|
}
|
|
|
|
The return value for get_option will be an unsigned integer value for any
|
|
option code. If the option currently is a pointer to pci_region, it will
|
|
return an index for get_region function. Special case has to be made for
|
|
PCI_OPT_CFG_ADDR, which should be interpreted as a pointer, but it is only
|
|
used for equality in find_hose_by_cfg_addr, and thus can be returned as an
|
|
uint. Other function using cfg_addr value are read/write functions for
|
|
specific drivers (especially ops for indirect bridges), and thus have access
|
|
to private_data of the driver instance.
|
|
|
|
The config table accessor will return a pointer to a NULL-terminated array of
|
|
pci_config_table, which is supplied by the board in platform_data, or NULL if
|
|
the board didn't specify one. This table is used to override PnP
|
|
auto-initialization, or to specific initialization functions for non-PNP
|
|
devices.
|
|
|
|
Transparent PCI-PCI bridges will get their own driver, and will forward all
|
|
operations to operations of their parent bus. This however makes it
|
|
impossible to use instances to identify devices, as not all devices will be
|
|
directly visible to the respective bus driver.
|
|
|
|
Init functions of controller drivers will be moved to their respective
|
|
probe() functions, in accordance to the driver model.
|
|
|
|
The PCI core will handle all mapping functions currently found in pci.c, as
|
|
well as proxy functions for read/write operations of the drivers. The PCI
|
|
core will also handle bus scanning and device configuration.
|
|
|
|
The PnP helper functions currently in pci_auto.c will also be a part of PCI
|
|
core, but they will be exposed only to PCI controller drivers, not to other
|
|
device drivers.
|
|
|
|
The PCI API for device drivers will remain largely unchanged, most drivers
|
|
will require no changes at all, and all modifications will be limited to
|
|
changing the pci_controlle into instance*.
|
|
|
|
III) Analysis of in-tree drivers
|
|
--------------------------------
|
|
|
|
A) drivers in drivers/pci/
|
|
--------------------------
|
|
|
|
1) pci_indirect.c
|
|
-----------------
|
|
Shared driver for indirect PCI bridges, several CONFIG macros - will
|
|
require significant cleanup.
|
|
|
|
2) pci_ixp.c
|
|
------------
|
|
Standard driver, specifies all read/write functions separately.
|
|
|
|
3) pci_sh4.c
|
|
------------
|
|
Shared init function for SH4 drivers, uses dword for read/write ops.
|
|
|
|
4) pci_sh7751.c
|
|
---------------
|
|
Standard driver, uses SH4 shared init.
|
|
|
|
5) pci_sh7780.c
|
|
---------------
|
|
Standard driver, uses SH4 shared init.
|
|
|
|
6) tsi108_pci.c
|
|
---------------
|
|
Standard driver, uses dword for read/write ops.
|
|
|
|
7) fsl_pci_init.c
|
|
-----------------
|
|
Driver for PCI and PCI-e, uses indirect functions.
|
|
|
|
8) pci_ftpci100.c
|
|
-----------------
|
|
Standard driver, uses indirect functions, has separate scan/setup
|
|
functions.
|
|
|
|
B) driver in arch/
|
|
------------------
|
|
|
|
1) x86/lib/pci_type1.c
|
|
----------------------
|
|
Standard driver, specifies all read/write functions separately.
|
|
|
|
2) m68k/cpu/mcf5445x/pci.c
|
|
--------------------------
|
|
Standard driver, specifies all read/write functions separately.
|
|
|
|
3) m68k/cpu/mcf547x_8x/pci.c
|
|
----------------------------
|
|
Standard driver, specifies all read/write functions separately.
|
|
|
|
4) powerpc/cpu/mpc824x/pci.c
|
|
----------------------------
|
|
Standard driver, uses indirect functions, does not setup HW.
|
|
|
|
5) powerpc/cpu/mpc8260/pci.c
|
|
----------------------------
|
|
Standard driver, uses indirect functions.
|
|
|
|
6) powerpc/cpu/ppc4xx/4xx_pci.c
|
|
-------------------------------
|
|
Standard driver, uses indirect functions.
|
|
|
|
7) powerpc/cpu/ppc4xx/4xx_pcie.c
|
|
--------------------------------
|
|
PCI-e driver, specifies all read/write functions separately.
|
|
|
|
8) powerpc/cpu/mpc83xx/pci.c
|
|
----------------------------
|
|
Standard driver, uses indirect functions.
|
|
|
|
9) powerpc/cpu/mpc83xx/pcie.c
|
|
-----------------------------
|
|
PCI-e driver, specifies all read/write functions separately.
|
|
|
|
10) powerpc/cpu/mpc5xxx/pci_mpc5200.c
|
|
-------------------------------------
|
|
Standard driver, uses dword for read/write ops.
|
|
|
|
11) powerpc/cpu/mpc512x/pci.c
|
|
-----------------------------
|
|
Standard driver, uses indirect functions.
|
|
|
|
12) powerpc/cpu/mpc85xx/pci.c
|
|
-----------------------------
|
|
Standard driver, uses indirect functions, has two busses.
|
|
|
|
C) drivers in board/
|
|
--------------------
|
|
|
|
1) eltec/elppc/pci.c
|
|
--------------------
|
|
Standard driver, uses indirect functions.
|
|
|
|
2) amirix/ap1000/pci.c
|
|
----------------------
|
|
Standard driver, specifies all read/write functions separately.
|
|
|
|
3) prodrive/p3mx/pci.c
|
|
----------------------
|
|
Standard driver, uses dword for read/write ops, has two busses.
|
|
|
|
4) esd/cpci750/pci.c
|
|
--------------------
|
|
Standard driver, uses dword for read/write ops, has two busses.
|
|
|
|
5) esd/common/pci.c
|
|
-------------------
|
|
Standard driver, uses dword for read/write ops.
|
|
|
|
6) dave/common/pci.c
|
|
--------------------
|
|
Standard driver, uses dword for read/write ops.
|
|
|
|
7) ppmc7xx/pci.c
|
|
----------------
|
|
Standard driver, uses indirect functions.
|
|
|
|
9) Marvell/db64360/pci.c
|
|
------------------------
|
|
Standard driver, uses dword for read/write ops, has two busses.
|
|
|
|
10) Marvell/db64460/pci.c
|
|
-------------------------
|
|
Standard driver, uses dword for read/write ops, has two busses.
|
|
|
|
11) evb64260/pci.c
|
|
------------------
|
|
Standard driver, uses dword for read/write ops, has two busses.
|
|
|
|
12) armltd/integrator/pci.c
|
|
---------------------------
|
|
Standard driver, specifies all read/write functions separately.
|
|
|
|
All drivers will be moved to drivers/pci. Several drivers seem
|
|
similar/identical, especially those located under board, and may be merged
|
|
into one.
|
|
|