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linux_dsm_epyc7002/arch/mips/include/asm/dma-coherence.h

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MIPS: Add option to disable software I/O coherency. Some MIPS controllers have hardware I/O coherency. This patch detects those and turns off software coherency. A new kernel command line option also allows the user to manually turn software coherency on or off. Signed-off-by: Steven J. Hill <Steven.Hill@imgtec.com>
2013-03-26 01:47:29 +07:00
/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2006 Ralf Baechle <ralf@linux-mips.org>
*
*/
#ifndef __ASM_DMA_COHERENCE_H
#define __ASM_DMA_COHERENCE_H
MIPS: Sanitise coherentio semantics The coherentio variable has previously been used as a boolean value, indicating whether the user specified that coherent I/O should be enabled or disabled. It failed to take into account the case where the user does not specify any preference, in which case it makes sense that we should default to coherent I/O if the hardware supports it (hw_coherentio is non-zero). Introduce an enum to clarify the 3 different values of coherentio & use it throughout the code, modifying plat_device_is_coherent() & r4k_cache_init() to take into account the default case. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Cc: Paul Burton <paul.burton@imgtec.com> Patchwork: https://patchwork.linux-mips.org/patch/14347/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-10-06 00:18:14 +07:00
enum coherent_io_user_state {
IO_COHERENCE_DEFAULT,
IO_COHERENCE_ENABLED,
IO_COHERENCE_DISABLED,
};
MIPS: Support per-device DMA coherence On some MIPS systems, a subset of devices may have DMA coherent with CPU caches. For example in systems including a MIPS I/O Coherence Unit (IOCU), some devices may be connected to that IOCU whilst others are not. Prior to this patch, we have a plat_device_is_coherent() function but no implementation which does anything besides return a global true or false, optionally chosen at runtime. For devices such as those described above this is insufficient. Fix this by tracking DMA coherence on a per-device basis with a dma_coherent field in struct dev_archdata. Setting this from arch_setup_dma_ops() takes care of devices which set the dma-coherent property via device tree, and any PCI devices beneath a bridge described in DT, automatically. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14349/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-10-06 00:18:16 +07:00
#if defined(CONFIG_DMA_PERDEV_COHERENT)
/* Don't provide (hw_)coherentio to avoid misuse */
#elif defined(CONFIG_DMA_MAYBE_COHERENT)
MIPS: Sanitise coherentio semantics The coherentio variable has previously been used as a boolean value, indicating whether the user specified that coherent I/O should be enabled or disabled. It failed to take into account the case where the user does not specify any preference, in which case it makes sense that we should default to coherent I/O if the hardware supports it (hw_coherentio is non-zero). Introduce an enum to clarify the 3 different values of coherentio & use it throughout the code, modifying plat_device_is_coherent() & r4k_cache_init() to take into account the default case. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Cc: Paul Burton <paul.burton@imgtec.com> Patchwork: https://patchwork.linux-mips.org/patch/14347/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-10-06 00:18:14 +07:00
extern enum coherent_io_user_state coherentio;
MIPS: Add option to disable software I/O coherency. Some MIPS controllers have hardware I/O coherency. This patch detects those and turns off software coherency. A new kernel command line option also allows the user to manually turn software coherency on or off. Signed-off-by: Steven J. Hill <Steven.Hill@imgtec.com>
2013-03-26 01:47:29 +07:00
extern int hw_coherentio;
MIPS: improve checks for noncoherent DMA Only one MIPS development board actually supports enabling/disabling DMA coherency at runtime, so it's not a good idea to push the overhead of checking that configuration setting onto every other supported target as well. Signed-off-by: Felix Fietkau <nbd@openwrt.org> Signed-off-by: John Crispin <blogic@openwrt.org> Patchwork: http://patchwork.linux-mips.org/patch/5912/
2013-09-27 19:41:44 +07:00
#else
#ifdef CONFIG_DMA_COHERENT
MIPS: Sanitise coherentio semantics The coherentio variable has previously been used as a boolean value, indicating whether the user specified that coherent I/O should be enabled or disabled. It failed to take into account the case where the user does not specify any preference, in which case it makes sense that we should default to coherent I/O if the hardware supports it (hw_coherentio is non-zero). Introduce an enum to clarify the 3 different values of coherentio & use it throughout the code, modifying plat_device_is_coherent() & r4k_cache_init() to take into account the default case. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Cc: Paul Burton <paul.burton@imgtec.com> Patchwork: https://patchwork.linux-mips.org/patch/14347/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-10-06 00:18:14 +07:00
#define coherentio IO_COHERENCE_ENABLED
MIPS: improve checks for noncoherent DMA Only one MIPS development board actually supports enabling/disabling DMA coherency at runtime, so it's not a good idea to push the overhead of checking that configuration setting onto every other supported target as well. Signed-off-by: Felix Fietkau <nbd@openwrt.org> Signed-off-by: John Crispin <blogic@openwrt.org> Patchwork: http://patchwork.linux-mips.org/patch/5912/
2013-09-27 19:41:44 +07:00
#else
MIPS: Sanitise coherentio semantics The coherentio variable has previously been used as a boolean value, indicating whether the user specified that coherent I/O should be enabled or disabled. It failed to take into account the case where the user does not specify any preference, in which case it makes sense that we should default to coherent I/O if the hardware supports it (hw_coherentio is non-zero). Introduce an enum to clarify the 3 different values of coherentio & use it throughout the code, modifying plat_device_is_coherent() & r4k_cache_init() to take into account the default case. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Cc: Paul Burton <paul.burton@imgtec.com> Patchwork: https://patchwork.linux-mips.org/patch/14347/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-10-06 00:18:14 +07:00
#define coherentio IO_COHERENCE_DISABLED
MIPS: improve checks for noncoherent DMA Only one MIPS development board actually supports enabling/disabling DMA coherency at runtime, so it's not a good idea to push the overhead of checking that configuration setting onto every other supported target as well. Signed-off-by: Felix Fietkau <nbd@openwrt.org> Signed-off-by: John Crispin <blogic@openwrt.org> Patchwork: http://patchwork.linux-mips.org/patch/5912/
2013-09-27 19:41:44 +07:00
#endif
#define hw_coherentio 0
#endif /* CONFIG_DMA_MAYBE_COHERENT */
MIPS: Add option to disable software I/O coherency. Some MIPS controllers have hardware I/O coherency. This patch detects those and turns off software coherency. A new kernel command line option also allows the user to manually turn software coherency on or off. Signed-off-by: Steven J. Hill <Steven.Hill@imgtec.com>
2013-03-26 01:47:29 +07:00
#endif
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