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Diffstat (limited to 'kernel/Documentation/memory-devices/ti-emif.txt')
| -rw-r--r-- | kernel/Documentation/memory-devices/ti-emif.txt | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/kernel/Documentation/memory-devices/ti-emif.txt b/kernel/Documentation/memory-devices/ti-emif.txt new file mode 100644 index 000000000..f4ad9a7d0 --- /dev/null +++ b/kernel/Documentation/memory-devices/ti-emif.txt @@ -0,0 +1,57 @@ +TI EMIF SDRAM Controller Driver: + +Author +======== +Aneesh V <aneesh@ti.com> + +Location +============ +driver/memory/emif.c + +Supported SoCs: +=================== +TI OMAP44xx +TI OMAP54xx + +Menuconfig option: +========================== +Device Drivers + Memory devices + Texas Instruments EMIF driver + +Description +=========== +This driver is for the EMIF module available in Texas Instruments +SoCs. EMIF is an SDRAM controller that, based on its revision, +supports one or more of DDR2, DDR3, and LPDDR2 SDRAM protocols. +This driver takes care of only LPDDR2 memories presently. The +functions of the driver includes re-configuring AC timing +parameters and other settings during frequency, voltage and +temperature changes + +Platform Data (see include/linux/platform_data/emif_plat.h): +===================================================================== +DDR device details and other board dependent and SoC dependent +information can be passed through platform data (struct emif_platform_data) +- DDR device details: 'struct ddr_device_info' +- Device AC timings: 'struct lpddr2_timings' and 'struct lpddr2_min_tck' +- Custom configurations: customizable policy options through + 'struct emif_custom_configs' +- IP revision +- PHY type + +Interface to the external world: +================================ +EMIF driver registers notifiers for voltage and frequency changes +affecting EMIF and takes appropriate actions when these are invoked. +- freq_pre_notify_handling() +- freq_post_notify_handling() +- volt_notify_handling() + +Debugfs +======== +The driver creates two debugfs entries per device. +- regcache_dump : dump of register values calculated and saved for all + frequencies used so far. +- mr4 : last polled value of MR4 register in the LPDDR2 device. MR4 + indicates the current temperature level of the device. |