Device State Configuration Registers
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TI C6X SoCs contain a region of miscellaneous registers which provide various
function for SoC control or status. Details vary considerably among from SoC
to SoC with no two being alike.
In general, the Device State Configuraion Registers (DSCR) will provide one or
more configuration registers often protected by a lock register where one or
more key values must be written to a lock register in order to unlock the
configuration register for writes. These configuration register may be used to
enable (and disable in some cases) SoC pin drivers, select peripheral clock
sources (internal or pin), etc. In some cases, a configuration register is
write once or the individual bits are write once. In addition to device config,
the DSCR block may provide registers which which are used to reset peripherals,
provide device ID information, provide ethernet MAC addresses, as well as other
miscellaneous functions.
For device state control (enable/disable), each device control is assigned an
id which is used by individual device drivers to control the state as needed.
Required properties:
- compatible: must be "ti,c64x+dscr"
- reg: register area base and size
Optional properties:
NOTE: These are optional in that not all SoCs will have all properties. For
SoCs which do support a given property, leaving the property out of the
device tree will result in reduced functionality or possibly driver
failure.
- ti,dscr-devstat
offset of the devstat register
- ti,dscr-silicon-rev
offset, start bit, and bitsize of silicon revision field
- ti,dscr-rmii-resets
offset and bitmask of RMII reset field. May have multiple tuples if more
than one ethernet port is available.
- ti,dscr-locked-regs
possibly multiple tuples describing registers which are write protected by
a lock register. Each tuple consists of the register offset, lock register
offsset, and the key value used to unlock the register.
- ti,dscr-kick-regs
offset and key values of two "kick" registers used to write protect other
registers in DSCR. On SoCs using kick registers, the first key must be
written to the first kick register and the second key must be written to
the second register before other registers in the area are write-enabled.
- ti,dscr-mac-fuse-regs
MAC addresses are contained in two registers. Each element of a MAC address
is contained in a single byte. This property has two tuples. Each tuple has
a register offset and four cells representing bytes in the register from
most significant to least. The value of these four cells is the MAC byte
index (1-6) of the byte within the register. A value of 0 means the byte
is unused in the MAC address.
- ti,dscr-devstate-ctl-regs
This property describes the bitfields used to control the state of devices.
Each tuple describes a range of identical bitfields used to control one or
more devices (one bitfield per device). The layout of each tuple is:
start_id num_ids reg enable disable start_bit nbits
Where:
start_id is device id for the first device control in the range
num_ids is the number of device controls in the range
reg is the offset of the register holding the control bits
enable is the value to enable a device
disable is the value to disable a device (0xffffffff if cannot disable)
start_bit is the bit number of the first bit in the range
nbits is the number of bits per device control
- ti,dscr-devstate-stat-regs
This property describes the bitfields used to provide device state status
for device states controlled by the DSCR. Each tuple describes a range of
identical bitfields used to provide status for one or more devices (one
bitfield per device). The layout of each tuple is:
start_id num_ids reg enable disable start_bit nbits
Where:
start_id is device id for the first device status in the range
num_ids is the number of devices covered by the range
reg is the offset of the register holding the status bits
enable is the value indicating device is enabled
disable is the value indicating device is disabled
start_bit is the bit number of the first bit in the range
nbits is the number of bits per device status
- ti,dscr-privperm
Offset and default value for register used to set access privilege for
some SoC devices.
Example:
device-state-config-regs@2a80000 {
compatible = "ti,c64x+dscr";
reg = <0x02a80000 0x41000>;
ti,dscr-devstat = <0>;
ti,dscr-silicon-rev = <8 28 0xf>;
ti,dscr-rmii-resets = <0x40020 0x00040000>;
ti,dscr-locked-regs = <0x40008 0x40004 0x0f0a0b00>;
ti,dscr-devstate-ctl-regs =
<0 12 0x40008 1 0 0 2
12 1 0x40008 3 0 30 2
13 2 0x4002c 1 0xffffffff 0 1>;
ti,dscr-devstate-stat-regs =
<0 10 0x40014 1 0 0 3
10 2 0x40018 1 0 0 3>;
ti,dscr-mac-fuse-regs = <0x700 1 2 3 4
0x704 5 6 0 0>;
ti,dscr-privperm = <0x41c 0xaaaaaaaa>;
ti,dscr-kick-regs = <0x38 0x83E70B13
0x3c 0x95A4F1E0>;
};