[PATCH v5 0/7] Add TI EMIF SDRAM controller driver
paul.gortmaker at windriver.com
Thu May 3 18:38:23 EDT 2012
On Fri, Apr 27, 2012 at 8:24 AM, Santosh Shilimkar
<santosh.shilimkar at ti.com> wrote:
> Add a driver for the EMIF SDRAM controller used in Texas Instrument SoCs
Can you send Greg a patch that adds proper dependencies to the Kconfig?
I was going to simply add an ARM dependency, but perhaps you want to
restrict it further to a subset of OMAP platforms?
At the moment it is causing build failures in other architectures.
> EMIF is an SDRAM controller that supports, based on its revision,
> one or more of LPDDR2/DDR2/DDR3 protocols.This driver adds support
> for LPDDR2.
> The driver supports the following features:
> - Calculates the DDR AC timing parameters to be set in EMIF
> registers using data from the device data-sheets and based
> on the DDR frequency. If data from data-sheets is not available
> default timing values from the JEDEC spec are used. These
> will be safe, but not necessarily optimal
> - API for changing timings during DVFS or at boot-up
> - Temperature alert configuration and handling of temperature
> alerts, if any for LPDDR2 devices
> * temperature alert is based on periodic polling of MR4 mode
> register in DDR devices automatically performed by hardware
> * timings are de-rated and brought back to nominal when
> temperature raises and falls respectively
> - Cache of calculated register values to avoid re-calculating
> The driver will need some minor updates when it is eventually
> integrated with Dynamic Voltage and Frequency Scaling (DVFS).
> This can not be done now as DVFS support is not available in
> the mainline yet.
> Discussions with Santosh Shilimkar <santosh.shilimkar at ti.com>
> were immensely helpful in shaping up the interfaces. Vibhore Vardhan
> <vvardhan at gmail.com> did the initial code snippet for thermal
> - The driver is tested on OMAP4430 SDP.
> - The driver in a slightly adapted form is also tested on OMAP5.
> - Since mainline kernel doesn't have DVFS support yet,
> testing was done using a test module.
> - Temperature alert handling was tested with simulated interrupts
> and faked temperature values as testing all cases in real-life
> scenarios is difficult.
> - Tested the driver as a module
> Cc: Greg KH <greg at kroah.com>
> - Moved the EMIF driver to drivers/memory as per discussion thread 
> - Converted instances of EXPORT_SYMBOL to EXPORT_SYMBOL_GPL
> - Removed un-necessary "#ifndef __ASSEMBLY__'
> - Minor formatting fix
> - Fixed a bug found in the implementation of errata i728
> - Fixed the value of frequency printed in debugfs
> - Dropped the hwmod patch as Paul has already posted a
> a hwmod series  that adds hwmod for EMIF
> - Converted instances of __init to __init_or_module
>  http://thread.gmane.org/gmane.linux.ports.arm.omap/72855
>  https://lkml.org/lkml/2012/4/12/173
> Aneesh V (7):
> ddr: add LPDDR2 data from JESD209-2
> memory: emif: add register definitions for EMIF
> memory: emif: add basic infrastructure for EMIF driver
> memory: emif: handle frequency and voltage change events
> memory: emif: add interrupt and temperature handling
> memory: emif: add one-time settings
> memory: emif: add debugfs entries for emif
> Documentation/memory-devices/ti-emif.txt | 57 +
> drivers/Kconfig | 4 +
> drivers/Makefile | 3 +
> drivers/memory/Kconfig | 22 +
> drivers/memory/Makefile | 5 +
> drivers/memory/emif.c | 1670 ++++++++++++++++++++++++++++++
> drivers/memory/emif.h | 589 +++++++++++
> include/linux/platform_data/emif_plat.h | 128 +++
> include/memory/jedec_ddr.h | 175 ++++
> lib/Kconfig | 8 +
> lib/Makefile | 2 +
> lib/jedec_ddr_data.c | 135 +++
> 12 files changed, 2798 insertions(+), 0 deletions(-)
> create mode 100644 Documentation/memory-devices/ti-emif.txt
> create mode 100644 drivers/memory/Kconfig
> create mode 100644 drivers/memory/Makefile
> create mode 100644 drivers/memory/emif.c
> create mode 100644 drivers/memory/emif.h
> create mode 100644 include/linux/platform_data/emif_plat.h
> create mode 100644 include/memory/jedec_ddr.h
> create mode 100644 lib/jedec_ddr_data.c
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