Root/
1 | SM501 Driver |
2 | ============ |
3 | |
4 | Copyright 2006, 2007 Simtec Electronics |
5 | |
6 | The Silicon Motion SM501 multimedia companion chip is a multifunction device |
7 | which may provide numerous interfaces including USB host controller USB gadget, |
8 | asynchronous serial ports, audio functions, and a dual display video interface. |
9 | The device may be connected by PCI or local bus with varying functions enabled. |
10 | |
11 | Core |
12 | ---- |
13 | |
14 | The core driver in drivers/mfd provides common services for the |
15 | drivers which manage the specific hardware blocks. These services |
16 | include locking for common registers, clock control and resource |
17 | management. |
18 | |
19 | The core registers drivers for both PCI and generic bus based |
20 | chips via the platform device and driver system. |
21 | |
22 | On detection of a device, the core initialises the chip (which may |
23 | be specified by the platform data) and then exports the selected |
24 | peripheral set as platform devices for the specific drivers. |
25 | |
26 | The core re-uses the platform device system as the platform device |
27 | system provides enough features to support the drivers without the |
28 | need to create a new bus-type and the associated code to go with it. |
29 | |
30 | |
31 | Resources |
32 | --------- |
33 | |
34 | Each peripheral has a view of the device which is implicitly narrowed to |
35 | the specific set of resources that peripheral requires in order to |
36 | function correctly. |
37 | |
38 | The centralised memory allocation allows the driver to ensure that the |
39 | maximum possible resource allocation can be made to the video subsystem |
40 | as this is by-far the most resource-sensitive of the on-chip functions. |
41 | |
42 | The primary issue with memory allocation is that of moving the video |
43 | buffers once a display mode is chosen. Indeed when a video mode change |
44 | occurs the memory footprint of the video subsystem changes. |
45 | |
46 | Since video memory is difficult to move without changing the display |
47 | (unless sufficient contiguous memory can be provided for the old and new |
48 | modes simultaneously) the video driver fully utilises the memory area |
49 | given to it by aligning fb0 to the start of the area and fb1 to the end |
50 | of it. Any memory left over in the middle is used for the acceleration |
51 | functions, which are transient and thus their location is less critical |
52 | as it can be moved. |
53 | |
54 | |
55 | Configuration |
56 | ------------- |
57 | |
58 | The platform device driver uses a set of platform data to pass |
59 | configurations through to the core and the subsidiary drivers |
60 | so that there can be support for more than one system carrying |
61 | an SM501 built into a single kernel image. |
62 | |
63 | The PCI driver assumes that the PCI card behaves as per the Silicon |
64 | Motion reference design. |
65 | |
66 | There is an errata (AB-5) affecting the selection of the |
67 | of the M1XCLK and M1CLK frequencies. These two clocks |
68 | must be sourced from the same PLL, although they can then |
69 | be divided down individually. If this is not set, then SM501 may |
70 | lock and hang the whole system. The driver will refuse to |
71 | attach if the PLL selection is different. |
72 |
Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master
Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9