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2023-03-09misc: sram: Improve and simplify clk handlingUwe Kleine-König1-1/+0
The current code tries to get an associated clk, ignores any errors in the process and if there is a clock enables it unconditionally for the whole lifetime of the sram device. Instead use an "optional" variant of devm_clk_get() which handles the case where no clk is needed for the sram device and do proper error handling for the remaining error cases. Also use an "enabled" variant of devm_clk_get() to simplify. With that .probe() is the only function using struct sram_dev::clk, so it can be replaced by a local variable. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de> Link: https://lore.kernel.org/r/20230302091251.1852454-1-u.kleine-koenig@pengutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-08-05misc: sram: Only map reserved areas in Tegra SYSRAMMikko Perttunen1-0/+9
On Tegra186 and later, a portion of the SYSRAM may be reserved for use by TZ. Non-TZ memory accesses to this portion, including speculative accesses, trigger SErrors that bring down the system. This does also happen in practice occasionally (due to speculative accesses). To fix the issue, add a flag to the SRAM driver to only map the device tree-specified reserved areas depending on a flag set based on the compatibility string. This would not affect non-Tegra systems that rely on the entire thing being memory mapped. If 64K pages are being used, we cannot exactly map the 4K regions that are placed in SYSRAM - ioremap code instead aligns to closest 64K pages. However, since in practice the non-accessible memory area is 64K aligned, these mappings do not overlap with the non-accessible memory area and things work out. Reviewed-by: Mian Yousaf Kaukab <ykaukab@suse.de> Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com> Link: https://lore.kernel.org/r/20210715103423.1811101-1-mperttunen@nvidia.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-19treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500Thomas Gleixner1-4/+1
Based on 2 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation # extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 4122 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Enrico Weigelt <info@metux.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-25misc: sram: Integrate protect-exec reserved sram area typeDave Gerlach1-0/+1
Introduce a new "protect-exec" reserved sram area type which is makes use of the the existing functionality provided for the "pool" sram region type for use with the genalloc framework and with the added requirement that it be maintained as read-only and executable while allowing for an arbitrary number of drivers to share the space. This introduces a common way to maintain a region of sram as read-only and executable and also introduces a helper function, sram_exec_copy, which allows for copying data to this protected region while maintaining locking to avoid conflicts between multiple users of the same space. A region of memory that is marked with the "protect-exec" flag in the device tree also has the requirement of providing a page aligned block of memory so that the page attribute manipulation does not affect surrounding regions. Also, selectively enable this only for builds that support set_memory_* calls, for now just ARM, through the use of Kconfig. Signed-off-by: Dave Gerlach <d-gerlach@ti.com> Acked-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-25misc: sram: Introduce support code for protect-exec sram typeDave Gerlach1-0/+18
Some platforms, like many ARM SoCs, require the ability to run code from on-chip memory like SRAM for tasks like reconfiguring the SDRAM controller or entering low-power sleep modes. In order to do this we must be able to allocate memory that the code can be copied to but then change the mapping to be read-only and executable so that no memory is both writable and executable at the same time to avoid opening any unneccesary security holes. By using the existing "pool" partition type that the SRAM driver allows we can create a memory space that will already be exposed by the genalloc framework to allow for allocating memory but we must extend this to meet the executable requirements. By making use of various set_memory_* APIs we can change the attributes of pages to make them writable for code upload but then read-only and executable when we want to actually run code. Because SRAM is a shared resource we need a centralized manager of these set memory calls. Because the SRAM driver itself is responsible for allocating the memory we can introduce a sram_copy_exec API for the driver that works like memcpy but also manages the page attributes and locking to allow multiple users of the same SRAM space to all copy their code over independent of other each before starting execution. It is maintained in a separate file from the core SRAM driver to allow it to be selectively built depending on whether or not a platform has the appropriate set_memory_* APIs. A future patch will integrate it with the core SRAM driver. Signed-off-by: Dave Gerlach <d-gerlach@ti.com> Acked-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-25misc: sram: Split sram data structures into local headerDave Gerlach1-0/+39
In preparation of a coming file split of the sram driver, move the common data structures into a local header file that can be shared between files related to the sram driver. Signed-off-by: Dave Gerlach <d-gerlach@ti.com> Acked-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>