[4/5] EDAC, dsm_edac: Wrap ACPI DSM methods for address translation

["Luck, Tony" <tony.luck@intel.com>]

Added linux-acpi list to Cc:

On Sat, Oct 06, 2018 at 10:44:56PM +0200, Borislav Petkov wrote:
> On Fri, Oct 05, 2018 at 03:25:57PM -0700, Luck, Tony wrote:
> > It's like acpi_extlog.c in that it uses an ACPI DSM. Also related
> > to error reporting.  No, we aren't abandoning extlog, but it seems
> > that fewer OEMs than we hoped are adopting eMCA and implementing
> > the extended log in their BIOS.
> 
> Ok, but what is the difference with this DSM thing and why would OEMs
> use that? They get it for free from you? Or?

This shouldn't conflict with other BIOS "value add" code for firmware
first mode, etc. 

Yes, they get it for free with the reference/example BIOS code.

> > So I dropped Qiuxu's code into a blender and ran it on high
> > for a few minutes.  Below is an RFC patch (compiles, but
> > otherwise untested) to see what things would looks like with
> > a built in ACPI block with no registrations to EDAC core, or
> > other stuff that is specific to the EDAC usage model.
> 
> Looks nice and clean to me.

Thanks!

> > +int adxl_count;
> > +EXPORT_SYMBOL_GPL(adxl_count);
> 
> That's the length of the address components adxl_component_names array?

Yes. But see below.

> > +char **adxl_component_names;
> > +EXPORT_SYMBOL_GPL(adxl_component_names);
> 
> I guess I'm still unclear on how this is going to be used...

Comments added in new version to save people from mailing list
archeology.

> aha, the DSM replies with a bunch of components which map to the names
> and they'll get filled up by BIOS and the driver simply dumps them.
> Something along those lines at least.
> 
> So you don't need count if you NULL-terminate the names array, right?
> 
> So you can simply do
> 
> 	kcalloc(cnt + 1, ...
> 
> and the last element will be NULL.

Good idea. Done in new version, and the EXPORT_SYMBOL_GPL(adxl_count) is
gone.

Still untested ... Qiuxu, can you try this out please.

Rafael: Does this look like something you can merge (once we
clean up any minor style stuff you find).

-Tony

diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index dd1eea90f67f..327c93b51cb7 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -498,6 +498,16 @@ config ACPI_EXTLOG
 	  driver adds support for that functionality with corresponding
 	  tracepoint which carries that information to userspace.
 
+config ACPI_ADXL
+	bool "Physical address to DIMM address translation"
+	def_bool n
+	help
+	  Enable interface that calls into BIOS using a DSM (device
+	  specific method) to convert system physical addresses
+	  to DIMM (socket, channel, rank, dimm, etc.).
+	  Only available on some servers.
+	  Used by newer EDAC drivers.
+
 menuconfig PMIC_OPREGION
 	bool "PMIC (Power Management Integrated Circuit) operation region support"
 	help
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 6d59aa109a91..edc039313cd6 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -61,6 +61,9 @@ acpi-$(CONFIG_ACPI_LPIT)	+= acpi_lpit.o
 acpi-$(CONFIG_ACPI_GENERIC_GSI) += irq.o
 acpi-$(CONFIG_ACPI_WATCHDOG)	+= acpi_watchdog.o
 
+# Address translation
+acpi-$(CONFIG_ACPI_ADXL)	+= acpi_adxl.o
+
 # These are (potentially) separate modules
 
 # IPMI may be used by other drivers, so it has to initialise before them
diff --git a/drivers/acpi/acpi_adxl.c b/drivers/acpi/acpi_adxl.c
new file mode 100644
index 000000000000..01d2b4d06430
--- /dev/null
+++ b/drivers/acpi/acpi_adxl.c
@@ -0,0 +1,179 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Address translation interface via ACPI DSM.
+ * Copyright (C) 2018 Intel Corporation
+ */
+
+#ifdef CONFIG_ACPI_ADXL
+#include <linux/acpi.h>
+#include <linux/adxl.h>
+
+#define ADXL_REVISION			0x1
+#define ADXL_IDX_GET_ADDR_PARAMS	0x1
+#define ADXL_IDX_FORWARD_TRANSLATE	0x2
+#define ACPI_ADXL_PATH			"\\_SB.ADXL"
+
+#undef pr_fmt
+#define pr_fmt(fmt) "ADXL: " fmt
+
+static acpi_handle handle;
+static union acpi_object *params;
+static const guid_t adxl_guid =
+	GUID_INIT(0xAA3C050A, 0x7EA4, 0x4C1F,
+		  0xAF, 0xDA, 0x12, 0x67, 0xDF, 0xD3, 0xD4, 0x8D);
+
+static char **adxl_component_names;
+
+static union acpi_object *adxl_dsm(int cmd, union acpi_object argv[])
+{
+	union acpi_object *obj, *o;
+
+	obj = acpi_evaluate_dsm_typed(handle, &adxl_guid, ADXL_REVISION,
+				      cmd, argv, ACPI_TYPE_PACKAGE);
+	if (!obj) {
+		pr_debug("Empty obj\n");
+		goto out;
+	}
+
+	if (obj->package.count != 2) {
+		pr_debug("Bad pkg cnt %d\n", obj->package.count);
+		goto err;
+	}
+
+	o = obj->package.elements;
+	if (o->type != ACPI_TYPE_INTEGER) {
+		pr_debug("Bad 1st element type %d\n", o->type);
+		goto err;
+	}
+	if (o->integer.value) {
+		pr_debug("Bad ret val %llu\n", o->integer.value);
+		goto err;
+	}
+
+	o = obj->package.elements + 1;
+	if (o->type != ACPI_TYPE_PACKAGE) {
+		pr_debug("Bad 2nd element type %d\n", o->type);
+		goto err;
+	}
+	return obj;
+
+err:
+	ACPI_FREE(obj);
+out:
+	return obj;
+}
+
+/**
+ * adxl_get_component_names - get list of memory component names
+ * Returns NULL terminated list of string names
+ *
+ * Give the caller a pointer to the list of memory component names
+ * e.g. { "SystemAddress", "ProcessorSocketId", "ChannelId", ... NULL }
+ * Caller should count how many strings in order to allocate a buffer
+ * for the return from adxl_decode()
+ */
+char **adxl_get_component_names(void)
+{
+	return adxl_component_names;
+}
+EXPORT_SYMBOL_GPL(adxl_get_component_names);
+
+/**
+ * adxl_decode - ask BIOS to decode a system address to memory address
+ * @addr: the address to decode
+ * @component_values: pointer to array of values for each component
+ * Returns 0 on success, negative error code otherwise
+ *
+ * The index of each value returned in the array matches the index of
+ * each component name returned by adxl_get_component_names().
+ * Components that are not defined for this address translation (e.g.
+ * mirror channel number for a non-mirrored address) are set to ~0ull
+ */
+int adxl_decode(u64 addr, u64 component_values[])
+{
+	union acpi_object argv4[2], *results, *r;
+	int i, cnt;
+
+	if (!adxl_component_names)
+		return -EOPNOTSUPP;
+
+	argv4[0].type = ACPI_TYPE_PACKAGE;
+	argv4[0].package.count = 1;
+	argv4[0].package.elements = &argv4[1];
+	argv4[1].integer.type = ACPI_TYPE_INTEGER;
+	argv4[1].integer.value = addr;
+
+	results = adxl_dsm(ADXL_IDX_FORWARD_TRANSLATE, argv4);
+
+	if (!results)
+		return -EINVAL;
+
+	r = results->package.elements + 1;
+	cnt = r->package.count;
+	r = r->package.elements;
+
+	for (i = 0; i < cnt; i++)
+		component_values[i] = r[i].integer.value;
+
+	ACPI_FREE(results);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(adxl_decode);
+
+static bool adxl_detect(void)
+{
+	char *path = ACPI_ADXL_PATH;
+	union acpi_object *p;
+	acpi_status status;
+	int i, cnt;
+
+	status = acpi_get_handle(NULL, path, &handle);
+	if (ACPI_FAILURE(status)) {
+		pr_debug("No ACPI handle for path %s\n", path);
+		return false;
+	}
+
+	if (!acpi_has_method(handle, "_DSM")) {
+		pr_debug("No DSM method\n");
+		return false;
+	}
+
+	if (!acpi_check_dsm(handle, &adxl_guid, ADXL_REVISION,
+			    ADXL_IDX_GET_ADDR_PARAMS |
+			    ADXL_IDX_FORWARD_TRANSLATE)) {
+		pr_debug("No ADXL DSM methods\n");
+		return false;
+	}
+
+	params = adxl_dsm(ADXL_IDX_GET_ADDR_PARAMS, NULL);
+	if (!params) {
+		pr_debug("Failed to get params\n");
+		return false;
+	}
+
+	p = params->package.elements + 1;
+	cnt = p->package.count;
+	p = p->package.elements;
+
+	adxl_component_names = kcalloc(cnt + 1, sizeof(char *), GFP_KERNEL);
+	if (!adxl_component_names) {
+		ACPI_FREE(params);
+		return false;
+	}
+
+	for (i = 0; i < cnt; i++)
+		adxl_component_names[i] = p[i].string.pointer;
+
+	return true;
+}
+
+static int __init adxl_init(void)
+{
+	if (!adxl_detect())
+		return -ENODEV;
+	return 0;
+}
+subsys_initcall(adxl_init);
+
+#endif /* CONFIG_ACPI_ADXL */
diff --git a/include/linux/adxl.h b/include/linux/adxl.h
new file mode 100644
index 000000000000..96d356a06e8b
--- /dev/null
+++ b/include/linux/adxl.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Address translation interface via ACPI DSM.
+ * Copyright (C) 2018 Intel Corporation
+ */
+
+#ifndef _LINUX_ADXL_H
+#define _LINUX_ADXL_H
+
+#ifdef CONFIG_ACPI_ADXL
+char **adxl_get_component_names(void);
+int adxl_decode(u64 addr, u64 component_values[]);
+#else
+static inline char **adxl_get_component_names(void)
+{
+	return NULL;
+}
+
+static inline int adxl_decode(u64 addr, u64 component_values[])
+{
+	return -EOPNOTSUPP;
+}
+#endif
+
+#endif /* _LINUX_ADXL_H */