7095c99a87
This commit adds support for CBMEM in sysfs. Useful for systems without access to /dev/mem e.g. Android. Linux kernel driver: drivers/firmware/google/cbmem.c Linux driver Kconfig: CONFIG_GOOGLE_CBMEM BUG=b:391874512 TEST=(devmem) cbmem -l; cbmem -x; cbmem -r 434f4e53; cbmem -t; cbmem -a 1200 TEST=modprobe cbmem; cbmem -l; cbmem -x; cbmem -r 434f4e53; cbmem -t; cbmem -a 1200 Change-Id: I527889509ffc84203be42d0160e5363c60eafd02 Signed-off-by: Jakub Czapiga <czapiga@google.com> Reviewed-on: https://review.coreboot.org/c/coreboot/+/86606 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Julius Werner <jwerner@chromium.org>
95 lines
2.5 KiB
C
95 lines
2.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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#include <stdbool.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include "cbmem_util.h"
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/* "ANY" (0) means no backend is active. */
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static enum cbmem_drv_backend_type active_backend = CBMEM_DRV_BACKEND_ANY;
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static const char no_backend_error_message[] =
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"No active/initialized CBMEM backend detected. Terminating.\n";
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static bool init_specific_backend(enum cbmem_drv_backend_type backend, bool writeable)
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{
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switch (backend) {
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case CBMEM_DRV_BACKEND_DEVMEM:
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if (!cbmem_devmem_init(writeable))
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return false;
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debug("Initialized CBMEM backend: devmem\n");
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break;
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case CBMEM_DRV_BACKEND_SYSFS:
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if (!cbmem_sysfs_init())
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return false;
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debug("Initialized CBMEM backend: sysfs\n");
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break;
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default:
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die("Unsupported backend selected. Terminating.\n");
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}
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active_backend = backend;
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return true;
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}
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bool cbmem_drv_init(enum cbmem_drv_backend_type backend, bool writeable)
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{
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if (backend != CBMEM_DRV_BACKEND_ANY)
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return init_specific_backend(backend, writeable);
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/* First try SYSFS backend as it's more secure. */
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if (!init_specific_backend(CBMEM_DRV_BACKEND_SYSFS, writeable))
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return init_specific_backend(CBMEM_DRV_BACKEND_DEVMEM, writeable);
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return true;
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}
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void cbmem_drv_terminate(void)
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{
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/* Only /dev/mem driver requires termination. */
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if (active_backend == CBMEM_DRV_BACKEND_DEVMEM)
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cbmem_devmem_terminate();
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active_backend = CBMEM_DRV_BACKEND_ANY;
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}
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bool cbmem_drv_get_cbmem_entry(uint32_t id, uint8_t **buf_out, size_t *size_out, uint64_t *addr_out)
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{
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switch (active_backend) {
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case CBMEM_DRV_BACKEND_DEVMEM:
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return cbmem_devmem_get_cbmem_entry(id, buf_out, size_out, addr_out);
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case CBMEM_DRV_BACKEND_SYSFS:
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return cbmem_sysfs_get_cbmem_entry(id, buf_out, size_out, addr_out);
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default:
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die(no_backend_error_message);
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}
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return false;
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}
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bool cbmem_drv_write_cbmem_entry(uint32_t id, uint8_t *buf, size_t buf_size)
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{
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switch (active_backend) {
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case CBMEM_DRV_BACKEND_DEVMEM:
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return cbmem_devmem_write_cbmem_entry(id, buf, buf_size);
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case CBMEM_DRV_BACKEND_SYSFS:
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return cbmem_sysfs_write_cbmem_entry(id, buf, buf_size);
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default:
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die(no_backend_error_message);
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}
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return false;
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}
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void cbmem_drv_foreach_cbmem_entry(cbmem_iterator_callback cb, void *data, bool with_contents)
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{
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switch (active_backend) {
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case CBMEM_DRV_BACKEND_DEVMEM:
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cbmem_devmem_foreach_cbmem_entry(cb, data, with_contents);
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break;
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case CBMEM_DRV_BACKEND_SYSFS:
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cbmem_sysfs_foreach_cbmem_entry(cb, data, with_contents);
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break;
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default:
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die(no_backend_error_message);
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}
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}
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