linux-stable.git/drivers/memory/emif.c, branch linux-4.9.y

memory: emif: check the pointer temp in get_device_details()

2022-04-20T07:06:33+00:00

[ Upstream commit 5b5ab1bfa1898c6d52936a57c25c5ceba2cb2f87 ]

The pointer temp is allocated by devm_kzalloc(), so it should be
checked for error handling.

Fixes: 7ec944538dde ("memory: emif: add basic infrastructure for EMIF driver")
Signed-off-by: Jia-Ju Bai 
Link: https://lore.kernel.org/r/20220225132552.27894-1-baijiaju1990@gmail.com
Signed-off-by: Krzysztof Kozlowski 
Signed-off-by: Sasha Levin

memory: emif: Add check for setup_interrupts

2022-04-20T07:06:33+00:00

[ Upstream commit fd7bd80b46373887b390852f490f21b07e209498 ]

As the potential failure of the devm_request_threaded_irq(),
it should be better to check the return value of the
setup_interrupts() and return error if fails.

Fixes: 68b4aee35d1f ("memory: emif: add interrupt and temperature handling")
Signed-off-by: Jiasheng Jiang 
Link: https://lore.kernel.org/r/20220224025444.3256530-1-jiasheng@iscas.ac.cn
Signed-off-by: Krzysztof Kozlowski 
Signed-off-by: Sasha Levin

memory: emif: Remove bogus debugfs error handling

2020-11-10T09:23:55+00:00

[ Upstream commit fd22781648080cc400772b3c68aa6b059d2d5420 ]

Callers are generally not supposed to check the return values from
debugfs functions.  Debugfs functions never return NULL so this error
handling will never trigger.  (Historically debugfs functions used to
return a mix of NULL and error pointers but it was eventually deemed too
complicated for something which wasn't intended to be used in normal
situations).

Delete all the error handling.

Signed-off-by: Dan Carpenter 
Acked-by: Santosh Shilimkar 
Link: https://lore.kernel.org/r/20200826113759.GF393664@mwanda
Signed-off-by: Krzysztof Kozlowski 
Signed-off-by: Sasha Levin

drivers/memory: don't check resource with devm_ioremap_resource

2013-05-18T09:55:52+00:00

devm_ioremap_resource does sanity checks on the given resource. No need to
duplicate this in the driver.

Signed-off-by: Wolfram Sang

memory: emif: Load the correct custom config values from dt

2013-03-25T20:18:13+00:00

of_get_property returns value in Big Endian format.
Before using this value it should be converted to little endian
using be32_to_cpup().
Custom configs of emif are read from dt using of_get_property,
but these are not converted to litte endian format.
Correcting the same here.

Signed-off-by: Lokesh Vutla 
Acked-by: Santosh Shilimkar 
Signed-off-by: Greg Kroah-Hartman

memory: emif: errata i743: Prohibit usage of Power-Down mode

2013-03-25T20:18:13+00:00

ERRATA DESCRIPTION :
The EMIF supports power-down state for low power. The EMIF
automatically puts the SDRAM into power-down after the memory is
not accessed for a defined number of cycles and the
EMIF_PWR_MGMT_CTRL[10:8] REG_LP_MODE bit field is set to 0x4.
As the EMIF supports automatic output impedance calibration, a ZQ
calibration long command is issued every time it exits active
power-down and precharge power-down modes. The EMIF waits and
blocks any other command during this calibration.
The EMIF does not allow selective disabling of ZQ calibration upon
exit of power-down mode. Due to very short periods of power-down
cycles, ZQ calibration overhead creates bandwidth issues and
increases overall system power consumption. On the other hand,
issuing ZQ calibration long commands when exiting self-refresh is
still required.

WORKAROUND :
Because there is no power consumption benefit of the power-down due
to the calibration and there is a performance risk, the guideline
is to not allow power-down state and, therefore, to not have set
the EMIF_PWR_MGMT_CTRL[10:8] REG_LP_MODE bit field to 0x4.

This is applicable only for EMIF4D IP used in OMAP4 Soc's.

Signed-off-by: Grygorii Strashko 
Signed-off-by: Vitaly Chernooky 
Signed-off-by: Oleksandr Dmytryshyn 
Signed-off-by: Lokesh Vutla 
Acked-by: Santosh Shilimkar 
Signed-off-by: Greg Kroah-Hartman

memory: emif: Fix the incorrect 'size' parameter in memcpy

2013-03-25T20:18:12+00:00

The issue was that only the first timings table was added to the
emif platform data at the emif driver registration. All other
timings tables was filled with zeros. Now all emif timings table
are added to the platform data.

Signed-off-by: Oleksandr Dmytryshyn 
Signed-off-by: Lokesh Vutla 
Acked-by: Santosh Shilimkar 
Signed-off-by: Greg Kroah-Hartman

memory: emif: use restart if power_off not present when out of spec

2013-03-25T20:18:12+00:00

Some machine or kernel variants might have missed implementation
of power off handlers. We DONOT want to let the system be in
"out of spec" state in this condition. So, WARN and attempt
a machine restart in the hopes of clearing the out-of-spec
temperature condition.

NOTE: This is not the safest option, but safer than leaving the
system in unstable conditions.

Signed-off-by: Nishanth Menon 
Signed-off-by: Lokesh Vutla 
Acked-by: Santosh Shilimkar 
Signed-off-by: Greg Kroah-Hartman

memory: emif: Handle devices which are not rated for >85C

2013-03-25T20:18:12+00:00

As per JESD209-2E specification for LPDDR2,
      http://www.jedec.org/standards-documents/results/jesd209-2E
Table 73, LPDDR2 memories come in two flavors - Standard and
Extended. The Standard types can operate from -25C to +85C
However, beyond that and upto +105C can only be supported by
Extended types.

Unfortunately, it seems there is no info in MR0(device info) or
MR[1,2](device feature) for run time detection of this capability
as far as seen on the spec. Hence, we provide a custom_config
flag to be populated by platforms which have these "extended"
type memories.

For the "Standard" memories, we need to consider MR4 notifications
of temperature triggers >85C as equivalent to thermal shutdown
events (equivalent to Spec specified thermal shutdown events for
"extended" parts).

Reported-by: Richard Woodruff 
Signed-off-by: Nishanth Menon 
Signed-off-by: Lokesh Vutla 
Acked-by: Santosh Shilimkar 
Signed-off-by: Greg Kroah-Hartman

memory: emif: handle overflow for timing for LP mode

2013-03-25T20:18:12+00:00

In case the custom timings provide values which overflow
the maximum possible field value, warn and use maximum
permissible value.

Signed-off-by: Nishanth Menon 
Signed-off-by: Lokesh Vutla 
Acked-by: Santosh Shilimkar 
Signed-off-by: Greg Kroah-Hartman