This is my work to let decode-dimms work out of the box on most x86
desktop and laptop systems.
[PATCH 1/4] firmware: dmi: Remember the memory type
[PATCH 2/4] firmware: dmi: Add dmi_memdev_handle
[PATCH 3/4] i2c: smbus: Add a way to instantiate SPD EEPROMs automatically
[PATCH 4/4] i2c: i801: Instantiate SPD EEPROMs automatically
Changes since v1:
* Fix build warning and error reported by kbuild test bot for specific
kernel configurations
--
Jean Delvare
SUSE L3 Support
Store the memory type while walking the memory slots, and provide a
way to retrieve it later.
Signed-off-by: Jean Delvare <[email protected]>
---
drivers/firmware/dmi_scan.c | 25 ++++++++++++++++++++++++-
include/linux/dmi.h | 2 ++
2 files changed, 26 insertions(+), 1 deletion(-)
--- linux-5.3.orig/drivers/firmware/dmi_scan.c 2019-10-08 14:27:23.783640227 +0200
+++ linux-5.3/drivers/firmware/dmi_scan.c 2019-10-08 16:35:35.442803880 +0200
@@ -35,6 +35,7 @@ static struct dmi_memdev_info {
const char *bank;
u64 size; /* bytes */
u16 handle;
+ u8 type; /* DDR2, DDR3, DDR4 etc */
} *dmi_memdev;
static int dmi_memdev_nr;
@@ -391,7 +392,7 @@ static void __init save_mem_devices(cons
u64 bytes;
u16 size;
- if (dm->type != DMI_ENTRY_MEM_DEVICE || dm->length < 0x12)
+ if (dm->type != DMI_ENTRY_MEM_DEVICE || dm->length < 0x13)
return;
if (nr >= dmi_memdev_nr) {
pr_warn(FW_BUG "Too many DIMM entries in SMBIOS table\n");
@@ -400,6 +401,7 @@ static void __init save_mem_devices(cons
dmi_memdev[nr].handle = get_unaligned(&dm->handle);
dmi_memdev[nr].device = dmi_string(dm, d[0x10]);
dmi_memdev[nr].bank = dmi_string(dm, d[0x11]);
+ dmi_memdev[nr].type = d[0x12];
size = get_unaligned((u16 *)&d[0xC]);
if (size == 0)
@@ -1128,3 +1130,24 @@ u64 dmi_memdev_size(u16 handle)
return ~0ull;
}
EXPORT_SYMBOL_GPL(dmi_memdev_size);
+
+/**
+ * dmi_memdev_type - get the memory type
+ * @handle: DMI structure handle
+ *
+ * Return the DMI memory type of the module in the slot associated with the
+ * given DMI handle, or 0x0 if no such DMI handle exists.
+ */
+u8 dmi_memdev_type(u16 handle)
+{
+ int n;
+
+ if (dmi_memdev) {
+ for (n = 0; n < dmi_memdev_nr; n++) {
+ if (handle == dmi_memdev[n].handle)
+ return dmi_memdev[n].type;
+ }
+ }
+ return 0x0; /* Not a valid value */
+}
+EXPORT_SYMBOL_GPL(dmi_memdev_type);
--- linux-5.3.orig/include/linux/dmi.h 2019-10-04 16:14:24.575714482 +0200
+++ linux-5.3/include/linux/dmi.h 2019-10-08 17:42:19.726907967 +0200
@@ -113,6 +113,7 @@ extern int dmi_walk(void (*decode)(const
extern bool dmi_match(enum dmi_field f, const char *str);
extern void dmi_memdev_name(u16 handle, const char **bank, const char **device);
extern u64 dmi_memdev_size(u16 handle);
+extern u8 dmi_memdev_type(u16 handle);
#else
@@ -142,6 +143,7 @@ static inline bool dmi_match(enum dmi_fi
static inline void dmi_memdev_name(u16 handle, const char **bank,
const char **device) { }
static inline u64 dmi_memdev_size(u16 handle) { return ~0ul; }
+static inline u8 dmi_memdev_type(u16 handle) { return 0x0; }
static inline const struct dmi_system_id *
dmi_first_match(const struct dmi_system_id *list) { return NULL; }
--
Jean Delvare
SUSE L3 Support
Add a utility function dmi_memdev_handle() which returns the DMI
handle associated with a given memory slot. This will allow kernel
drivers to iterate over the memory slots.
Signed-off-by: Jean Delvare <[email protected]>
---
drivers/firmware/dmi_scan.c | 16 ++++++++++++++++
include/linux/dmi.h | 2 ++
2 files changed, 18 insertions(+)
--- linux-5.3.orig/drivers/firmware/dmi_scan.c 2019-10-10 11:33:02.871034637 +0200
+++ linux-5.3/drivers/firmware/dmi_scan.c 2019-10-10 11:45:37.275549638 +0200
@@ -1151,3 +1151,19 @@ u8 dmi_memdev_type(u16 handle)
return 0x0; /* Not a valid value */
}
EXPORT_SYMBOL_GPL(dmi_memdev_type);
+
+/**
+ * dmi_memdev_handle - get the DMI handle of a memory slot
+ * @slot: slot number
+ *
+ * Return the DMI handle associated with a given memory slot, or %0xFFFF
+ * if there is no such slot.
+ */
+u16 dmi_memdev_handle(int slot)
+{
+ if (dmi_memdev && slot >= 0 && slot < dmi_memdev_nr)
+ return dmi_memdev[slot].handle;
+
+ return 0xffff; /* Not a valid value */
+}
+EXPORT_SYMBOL_GPL(dmi_memdev_handle);
--- linux-5.3.orig/include/linux/dmi.h 2019-10-10 11:33:02.871034637 +0200
+++ linux-5.3/include/linux/dmi.h 2019-10-10 11:34:46.146337207 +0200
@@ -114,6 +114,7 @@ extern bool dmi_match(enum dmi_field f,
extern void dmi_memdev_name(u16 handle, const char **bank, const char **device);
extern u64 dmi_memdev_size(u16 handle);
extern u8 dmi_memdev_type(u16 handle);
+extern u16 dmi_memdev_handle(int slot);
#else
@@ -144,6 +145,7 @@ static inline void dmi_memdev_name(u16 h
const char **device) { }
static inline u64 dmi_memdev_size(u16 handle) { return ~0ul; }
static inline u8 dmi_memdev_type(u16 handle) { return 0x0; }
+static inline u16 dmi_memdev_handle(int slot) { return 0xffff; }
static inline const struct dmi_system_id *
dmi_first_match(const struct dmi_system_id *list) { return NULL; }
--
Jean Delvare
SUSE L3 Support
In simple cases we can instantiate SPD EEPROMs on the SMBus
automatically. Start with just DDR2, DDR3 and DDR4 on x86 for now,
and only for systems with no more than 4 memory slots. These
limitations may be lifted later.
Signed-off-by: Jean Delvare <[email protected]>
---
Changes since v1:
* Fixed build warning reported by kbuild test bot
drivers/i2c/i2c-smbus.c | 104 +++++++++++++++++++++++++++++++++++++++++++++-
include/linux/i2c-smbus.h | 8 +++
2 files changed, 110 insertions(+), 2 deletions(-)
--- linux-5.3.orig/drivers/i2c/i2c-smbus.c 2019-10-14 11:33:20.372781769 +0200
+++ linux-5.3/drivers/i2c/i2c-smbus.c 2019-10-14 16:42:12.815302881 +0200
@@ -3,10 +3,11 @@
* i2c-smbus.c - SMBus extensions to the I2C protocol
*
* Copyright (C) 2008 David Brownell
- * Copyright (C) 2010 Jean Delvare <[email protected]>
+ * Copyright (C) 2010-2019 Jean Delvare <[email protected]>
*/
#include <linux/device.h>
+#include <linux/dmi.h>
#include <linux/i2c.h>
#include <linux/i2c-smbus.h>
#include <linux/interrupt.h>
@@ -203,6 +204,107 @@ EXPORT_SYMBOL_GPL(i2c_handle_smbus_alert
module_i2c_driver(smbalert_driver);
+/*
+ * SPD is not part of SMBus but we include it here for convenience as the
+ * target systems are the same.
+ * Restrictions to automatic SPD instantiation:
+ * - Only works if all filled slots have the same memory type
+ * - Only works for DDR2, DDR3 and DDR4 for now
+ * - Only works on systems with 1 to 4 memory slots
+ */
+#if IS_ENABLED(CONFIG_DMI)
+void i2c_register_spd(struct i2c_adapter *adap)
+{
+ int n, slot_count = 0, dimm_count = 0;
+ u16 handle;
+ u8 common_mem_type = 0x0, mem_type;
+ u64 mem_size;
+ const char *name;
+
+ while ((handle = dmi_memdev_handle(slot_count)) != 0xffff) {
+ slot_count++;
+
+ /* Skip empty slots */
+ mem_size = dmi_memdev_size(handle);
+ if (!mem_size)
+ continue;
+
+ /* Skip undefined memory type */
+ mem_type = dmi_memdev_type(handle);
+ if (mem_type <= 0x02) /* Invalid, Other, Unknown */
+ continue;
+
+ if (!common_mem_type) {
+ /* First filled slot */
+ common_mem_type = mem_type;
+ } else {
+ /* Check that all filled slots have the same type */
+ if (mem_type != common_mem_type) {
+ dev_warn(&adap->dev,
+ "Different memory types mixed, not instantiating SPD\n");
+ return;
+ }
+ }
+ dimm_count++;
+ }
+
+ /* No useful DMI data, bail out */
+ if (!dimm_count)
+ return;
+
+ dev_info(&adap->dev, "%d/%d memory slots populated (from DMI)\n",
+ dimm_count, slot_count);
+
+ if (slot_count > 4) {
+ dev_warn(&adap->dev,
+ "Systems with more than 4 memory slots not supported yet, not instantiating SPD\n");
+ return;
+ }
+
+ switch (common_mem_type) {
+ case 0x13: /* DDR2 */
+ case 0x18: /* DDR3 */
+ case 0x1C: /* LPDDR2 */
+ case 0x1D: /* LPDDR3 */
+ name = "spd";
+ break;
+ case 0x1A: /* DDR4 */
+ case 0x1E: /* LPDDR4 */
+ name = "ee1004";
+ break;
+ default:
+ dev_info(&adap->dev,
+ "Memory type 0x%02x not supported yet, not instantiating SPD\n",
+ common_mem_type);
+ return;
+ }
+
+ /*
+ * We don't know in which slots the memory modules are. We could
+ * try to guess from the slot names, but that would be rather complex
+ * and unreliable, so better probe all possible addresses until we
+ * have found all memory modules.
+ */
+ for (n = 0; n < slot_count && dimm_count; n++) {
+ struct i2c_board_info info;
+ unsigned short addr_list[2];
+
+ memset(&info, 0, sizeof(struct i2c_board_info));
+ strlcpy(info.type, name, I2C_NAME_SIZE);
+ addr_list[0] = 0x50 + n;
+ addr_list[1] = I2C_CLIENT_END;
+
+ if (i2c_new_probed_device(adap, &info, addr_list, NULL)) {
+ dev_info(&adap->dev,
+ "Successfully instantiated SPD at 0x%hx\n",
+ addr_list[0]);
+ dimm_count--;
+ }
+ }
+}
+EXPORT_SYMBOL_GPL(i2c_register_spd);
+#endif
+
MODULE_AUTHOR("Jean Delvare <[email protected]>");
MODULE_DESCRIPTION("SMBus protocol extensions support");
MODULE_LICENSE("GPL");
--- linux-5.3.orig/include/linux/i2c-smbus.h 2019-10-14 11:33:20.372781769 +0200
+++ linux-5.3/include/linux/i2c-smbus.h 2019-10-14 16:44:22.636959738 +0200
@@ -2,7 +2,7 @@
/*
* i2c-smbus.h - SMBus extensions to the I2C protocol
*
- * Copyright (C) 2010 Jean Delvare <[email protected]>
+ * Copyright (C) 2010-2019 Jean Delvare <[email protected]>
*/
#ifndef _LINUX_I2C_SMBUS_H
@@ -44,4 +44,10 @@ static inline int of_i2c_setup_smbus_ale
}
#endif
+#if IS_ENABLED(CONFIG_I2C_SMBUS) && IS_ENABLED(CONFIG_DMI)
+void i2c_register_spd(struct i2c_adapter *adap);
+#else
+static inline void i2c_register_spd(struct i2c_adapter *adap) { }
+#endif
+
#endif /* _LINUX_I2C_SMBUS_H */
--
Jean Delvare
SUSE L3 Support
Call the function to instantiate SPD EEPROMs automatically on the
main SMBus controller.
Multiplexed SMBus systems are excluded for now as they are more
complex to handle.
Signed-off-by: Jean Delvare <[email protected]>
---
Changes since v1:
* Fixed build error reported by kbuild test robot
drivers/i2c/busses/i2c-i801.c | 6 ++++++
1 file changed, 6 insertions(+)
--- linux-5.4-rc7.orig/drivers/i2c/busses/i2c-i801.c 2019-11-18 10:21:39.688372006 +0100
+++ linux-5.4-rc7/drivers/i2c/busses/i2c-i801.c 2019-11-18 10:21:41.928402933 +0100
@@ -1320,6 +1320,12 @@ static void i801_probe_optional_slaves(s
if (is_dell_system_with_lis3lv02d())
register_dell_lis3lv02d_i2c_device(priv);
+
+ /* Instantiate SPD EEPROMs unless the SMBus is multiplexed */
+#if IS_ENABLED(CONFIG_I2C_MUX_GPIO)
+ if (!priv->mux_drvdata)
+#endif
+ i2c_register_spd(&priv->adapter);
}
#else
static void __init input_apanel_init(void) {}
--
Jean Delvare
SUSE L3 Support