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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: Aneesh V <aneesh@ti.com> Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Reviewed-by: Benoit Cousson <b-cousson@ti.com> [santosh.shilimkar@ti.com: Moved to drivers/memory from drivers/misc] Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Tested-by: Lokesh Vutla <lokeshvutla@ti.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
58 lines
1.8 KiB
Plaintext
58 lines
1.8 KiB
Plaintext
TI EMIF SDRAM Controller Driver:
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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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