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Commit 7ec94453 authored by Aneesh V's avatar Aneesh V Committed by Greg Kroah-Hartman
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memory: emif: add basic infrastructure for EMIF driver 



EMIF is an SDRAM controller used in various Texas Instruments
SoCs. EMIF supports, based on its revision, one or more of
LPDDR2/DDR2/DDR3 protocols.

Add the basic infrastructure for EMIF driver that includes
driver registration, probe, parsing of platform data etc.

Signed-off-by: default avatarAneesh V <aneesh@ti.com>
Reviewed-by: default avatarSantosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: default avatarBenoit Cousson <b-cousson@ti.com>
[santosh.shilimkar@ti.com: Moved to drivers/memory from drivers/misc]
Signed-off-by: default avatarSantosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: default avatarLokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 6c8b0906

Documentation/memory-devices/ti-emif.txt

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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.

drivers/Kconfig

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@@ -142,4 +142,6 @@ source "drivers/devfreq/Kconfig" 




source "drivers/extcon/Kconfig"

source "drivers/extcon/Kconfig"





source "drivers/memory/Kconfig"



endmenu
 
endmenu

drivers/Makefile

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@@ -135,3 +135,4 @@ obj-$(CONFIG_HYPERV) += hv/ 




obj-$(CONFIG_PM_DEVFREQ)	+= devfreq/

obj-$(CONFIG_PM_DEVFREQ)	+= devfreq/

obj-$(CONFIG_EXTCON)		+= extcon/

obj-$(CONFIG_EXTCON)		+= extcon/

obj-$(CONFIG_MEMORY)		+= memory/

drivers/memory/Kconfig

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#

# Memory devices

#



menuconfig MEMORY

	bool "Memory Controller drivers"



if MEMORY



config TI_EMIF

	tristate "Texas Instruments EMIF driver"

	select DDR

	help

	  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



endif

drivers/memory/Makefile

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#

# Makefile for memory devices

#



obj-$(CONFIG_TI_EMIF)		+= emif.o