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90 lines
2.7 KiB
Diff
90 lines
2.7 KiB
Diff
From 9090a0266eb13b823656216c665182d45a4cd19b Mon Sep 17 00:00:00 2001
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From: Krystian Hebel <krystian.hebel@3mdeb.com>
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Date: Tue, 28 Mar 2023 18:31:21 +0200
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Subject: [PATCH] drivers/firmware/google: expose CBMEM as sysfs file
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Signed-off-by: Krystian Hebel <krystian.hebel@3mdeb.com>
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---
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drivers/firmware/google/Kconfig | 8 ++++++
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drivers/firmware/google/coreboot_table.c | 33 ++++++++++++++++++++++++
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2 files changed, 41 insertions(+)
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diff --git a/drivers/firmware/google/Kconfig b/drivers/firmware/google/Kconfig
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index a3a6ca659ffa..2d18ee174043 100644
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--- a/drivers/firmware/google/Kconfig
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+++ b/drivers/firmware/google/Kconfig
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@@ -29,6 +29,14 @@ config GOOGLE_COREBOOT_TABLE
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device tree node /firmware/coreboot.
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If unsure say N.
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+config GOOGLE_COREBOOT_CBMEM
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+ bool "Expose CBMEM as file"
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+ depends on GOOGLE_COREBOOT_TABLE
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+ help
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+ This option exposes raw contents of coreboot's CBMEM to be consumed
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+ by userspace tools. Path to file: /sys/firmware/cbmem.
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+ If unsure say N.
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+
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config GOOGLE_COREBOOT_TABLE_ACPI
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tristate
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select GOOGLE_COREBOOT_TABLE
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diff --git a/drivers/firmware/google/coreboot_table.c b/drivers/firmware/google/coreboot_table.c
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index 8d132e4f008a..f93bdc49b1ac 100644
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--- a/drivers/firmware/google/coreboot_table.c
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+++ b/drivers/firmware/google/coreboot_table.c
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@@ -84,6 +84,18 @@ void coreboot_driver_unregister(struct coreboot_driver *driver)
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}
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EXPORT_SYMBOL(coreboot_driver_unregister);
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+#ifdef CONFIG_GOOGLE_COREBOOT_CBMEM
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+static ssize_t cbmem_read(struct file *filp, struct kobject *kobp,
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+ struct bin_attribute *bin_attr, char *buf,
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+ loff_t pos, size_t count)
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+{
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+ return memory_read_from_buffer(buf, count, &pos,
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+ bin_attr->private, bin_attr->size);
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+}
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+
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+static BIN_ATTR_RO(cbmem, 0);
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+#endif
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+
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static int coreboot_table_populate(struct device *dev, void *ptr)
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{
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int i, ret;
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@@ -160,11 +172,32 @@ static int coreboot_table_probe(struct platform_device *pdev)
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}
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memunmap(ptr);
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+#ifdef CONFIG_GOOGLE_COREBOOT_CBMEM
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+ res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
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+ if (res && res->start && res->end && resource_size(res)) {
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+ bin_attr_cbmem.size = resource_size(res);
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+ bin_attr_cbmem.private = memremap(res->start,
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+ resource_size(res),
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+ MEMREMAP_WB);
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+ if (sysfs_create_bin_file(firmware_kobj, &bin_attr_cbmem)) {
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+ bin_attr_cbmem.size = 0;
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+ bin_attr_cbmem.private = NULL;
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+ }
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+ }
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+#endif
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+
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return ret;
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}
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static int coreboot_table_remove(struct platform_device *pdev)
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{
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+#ifdef CONFIG_GOOGLE_COREBOOT_CBMEM
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+ if (bin_attr_cbmem.private) {
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+ sysfs_remove_bin_file(firmware_kobj, &bin_attr_cbmem);
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+ memunmap(bin_attr_cbmem.private);
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+ }
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+#endif
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+
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bus_unregister(&coreboot_bus_type);
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return 0;
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}
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--
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2.17.1
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