a098ecd2fa
Some systems are memory constrained but they need to load very large firmwares. The firmware subsystem allows drivers to request this firmware be loaded from the filesystem, but this requires that the entire firmware be loaded into kernel memory first before it's provided to the driver. This can lead to a situation where we map the firmware twice, once to load the firmware into kernel memory and once to copy the firmware into the final resting place. This creates needless memory pressure and delays loading because we have to copy from kernel memory to somewhere else. Let's add a request_firmware_into_buf() API that allows drivers to request firmware be loaded directly into a pre-allocated buffer. This skips the intermediate step of allocating a buffer in kernel memory to hold the firmware image while it's read from the filesystem. It also requires that drivers know how much memory they'll require before requesting the firmware and negates any benefits of firmware caching because the firmware layer doesn't manage the buffer lifetime. For a 16MB buffer, about half the time is spent performing a memcpy from the buffer to the final resting place. I see loading times go from 0.081171 seconds to 0.047696 seconds after applying this patch. Plus the vmalloc pressure is reduced. This is based on a patch from Vikram Mulukutla on codeaurora.org: https://www.codeaurora.org/cgit/quic/la/kernel/msm-3.18/commit/drivers/base/firmware_class.c?h=rel/msm-3.18&id=0a328c5f6cd999f5c591f172216835636f39bcb5 Link: http://lkml.kernel.org/r/20160607164741.31849-4-stephen.boyd@linaro.org Signed-off-by: Stephen Boyd <stephen.boyd@linaro.org> Cc: Mimi Zohar <zohar@linux.vnet.ibm.com> Cc: Vikram Mulukutla <markivx@codeaurora.org> Cc: Mark Brown <broonie@kernel.org> Cc: Ming Lei <ming.lei@canonical.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
88 lines
2.3 KiB
C
88 lines
2.3 KiB
C
#ifndef _LINUX_FIRMWARE_H
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#define _LINUX_FIRMWARE_H
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#include <linux/types.h>
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#include <linux/compiler.h>
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#include <linux/gfp.h>
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#define FW_ACTION_NOHOTPLUG 0
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#define FW_ACTION_HOTPLUG 1
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struct firmware {
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size_t size;
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const u8 *data;
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struct page **pages;
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/* firmware loader private fields */
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void *priv;
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};
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struct module;
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struct device;
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struct builtin_fw {
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char *name;
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void *data;
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unsigned long size;
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};
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/* We have to play tricks here much like stringify() to get the
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__COUNTER__ macro to be expanded as we want it */
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#define __fw_concat1(x, y) x##y
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#define __fw_concat(x, y) __fw_concat1(x, y)
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#define DECLARE_BUILTIN_FIRMWARE(name, blob) \
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DECLARE_BUILTIN_FIRMWARE_SIZE(name, &(blob), sizeof(blob))
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#define DECLARE_BUILTIN_FIRMWARE_SIZE(name, blob, size) \
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static const struct builtin_fw __fw_concat(__builtin_fw,__COUNTER__) \
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__used __section(.builtin_fw) = { name, blob, size }
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#if defined(CONFIG_FW_LOADER) || (defined(CONFIG_FW_LOADER_MODULE) && defined(MODULE))
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int request_firmware(const struct firmware **fw, const char *name,
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struct device *device);
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int request_firmware_nowait(
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struct module *module, bool uevent,
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const char *name, struct device *device, gfp_t gfp, void *context,
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void (*cont)(const struct firmware *fw, void *context));
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int request_firmware_direct(const struct firmware **fw, const char *name,
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struct device *device);
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int request_firmware_into_buf(const struct firmware **firmware_p,
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const char *name, struct device *device, void *buf, size_t size);
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void release_firmware(const struct firmware *fw);
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#else
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static inline int request_firmware(const struct firmware **fw,
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const char *name,
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struct device *device)
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{
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return -EINVAL;
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}
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static inline int request_firmware_nowait(
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struct module *module, bool uevent,
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const char *name, struct device *device, gfp_t gfp, void *context,
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void (*cont)(const struct firmware *fw, void *context))
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{
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return -EINVAL;
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}
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static inline void release_firmware(const struct firmware *fw)
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{
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}
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static inline int request_firmware_direct(const struct firmware **fw,
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const char *name,
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struct device *device)
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{
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return -EINVAL;
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}
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static inline int request_firmware_into_buf(const struct firmware **firmware_p,
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const char *name, struct device *device, void *buf, size_t size)
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{
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return -EINVAL;
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}
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#endif
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#endif
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