65 lines
1.8 KiB
ReStructuredText
65 lines
1.8 KiB
ReStructuredText
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.. SPDX-License-Identifier: GPL-2.0
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===============================
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TI EMIF SDRAM Controller Driver
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===============================
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Author
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======
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Aneesh V <aneesh@ti.com>
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Location
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========
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driver/memory/emif.c
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Supported SoCs:
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===============
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TI OMAP44xx
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TI OMAP54xx
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Menuconfig option:
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==================
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Device Drivers
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Memory devices
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Texas Instruments EMIF driver
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Description
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===========
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This driver is for the EMIF module available in Texas Instruments
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SoCs. EMIF is an SDRAM controller that, based on its revision,
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supports one or more of DDR2, DDR3, and LPDDR2 SDRAM protocols.
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This driver takes care of only LPDDR2 memories presently. The
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functions of the driver includes re-configuring AC timing
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parameters and other settings during frequency, voltage and
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temperature changes
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Platform Data (see include/linux/platform_data/emif_plat.h)
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===========================================================
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DDR device details and other board dependent and SoC dependent
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information can be passed through platform data (struct emif_platform_data)
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- DDR device details: 'struct ddr_device_info'
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- Device AC timings: 'struct lpddr2_timings' and 'struct lpddr2_min_tck'
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- Custom configurations: customizable policy options through
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'struct emif_custom_configs'
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- IP revision
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- PHY type
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Interface to the external world
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===============================
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EMIF driver registers notifiers for voltage and frequency changes
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affecting EMIF and takes appropriate actions when these are invoked.
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- freq_pre_notify_handling()
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- freq_post_notify_handling()
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- volt_notify_handling()
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Debugfs
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=======
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The driver creates two debugfs entries per device.
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- regcache_dump : dump of register values calculated and saved for all
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frequencies used so far.
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- mr4 : last polled value of MR4 register in the LPDDR2 device. MR4
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indicates the current temperature level of the device.
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