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Aneesh V7ec94452012-04-27 17:54:05 +05301TI EMIF SDRAM Controller Driver:
2
3Author
4========
5Aneesh V <aneesh@ti.com>
6
7Location
8============
9driver/memory/emif.c
10
11Supported SoCs:
12===================
13TI OMAP44xx
14TI OMAP54xx
15
16Menuconfig option:
17==========================
18Device Drivers
19 Memory devices
20 Texas Instruments EMIF driver
21
22Description
23===========
24This driver is for the EMIF module available in Texas Instruments
25SoCs. EMIF is an SDRAM controller that, based on its revision,
26supports one or more of DDR2, DDR3, and LPDDR2 SDRAM protocols.
27This driver takes care of only LPDDR2 memories presently. The
28functions of the driver includes re-configuring AC timing
29parameters and other settings during frequency, voltage and
30temperature changes
31
32Platform Data (see include/linux/platform_data/emif_plat.h):
33=====================================================================
34DDR device details and other board dependent and SoC dependent
35information can be passed through platform data (struct emif_platform_data)
36- DDR device details: 'struct ddr_device_info'
37- Device AC timings: 'struct lpddr2_timings' and 'struct lpddr2_min_tck'
38- Custom configurations: customizable policy options through
39 'struct emif_custom_configs'
40- IP revision
41- PHY type
42
43Interface to the external world:
44================================
45EMIF driver registers notifiers for voltage and frequency changes
46affecting EMIF and takes appropriate actions when these are invoked.
47- freq_pre_notify_handling()
48- freq_post_notify_handling()
49- volt_notify_handling()
50
51Debugfs
52========
53The driver creates two debugfs entries per device.
54- regcache_dump : dump of register values calculated and saved for all
55 frequencies used so far.
56- mr4 : last polled value of MR4 register in the LPDDR2 device. MR4
57 indicates the current temperature level of the device.