diff mbox

[RFC,2/4] firmware: dmi: Add function to look up a handle and return DIMM size

Message ID 2fae02861e5c446c0cdd30ba3e00fad55db97807.1512070562.git.tony.luck@intel.com (mailing list archive)
State Not Applicable, archived
Headers show

Commit Message

Tony Luck Nov. 30, 2017, 8:40 p.m. UTC
When we first scan the SMBIOS table, save the size of the DIMM.

Provide a function for other code (EDAC driver) to look up the size
of a DIMM from its SMBIOS handle.

Signed-off-by: Tony Luck <tony.luck@intel.com>
---
 drivers/firmware/dmi_scan.c | 29 +++++++++++++++++++++++++++++
 include/linux/dmi.h         |  2 ++
 2 files changed, 31 insertions(+)

Comments

Borislav Petkov Dec. 4, 2017, 9:38 p.m. UTC | #1
On Thu, Nov 30, 2017 at 12:40:40PM -0800, Tony Luck wrote:
> When we first scan the SMBIOS table, save the size of the DIMM.
> 
> Provide a function for other code (EDAC driver) to look up the size
> of a DIMM from its SMBIOS handle.
> 
> Signed-off-by: Tony Luck <tony.luck@intel.com>
> ---
>  drivers/firmware/dmi_scan.c | 29 +++++++++++++++++++++++++++++
>  include/linux/dmi.h         |  2 ++
>  2 files changed, 31 insertions(+)
> 
> diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
> index 783041964439..946e86fb1ec6 100644
> --- a/drivers/firmware/dmi_scan.c
> +++ b/drivers/firmware/dmi_scan.c
> @@ -37,6 +37,7 @@ static char dmi_ids_string[128] __initdata;
>  static struct dmi_memdev_info {
>  	const char *device;
>  	const char *bank;
> +	u64 size;
>  	u16 handle;
>  } *dmi_memdev;
>  static int dmi_memdev_nr;
> @@ -395,6 +396,8 @@ static void __init save_mem_devices(const struct dmi_header *dm, void *v)
>  {
>  	const char *d = (const char *)dm;
>  	static int nr;
> +	u64 bytes;
> +	u16 size;
>  
>  	if (dm->type != DMI_ENTRY_MEM_DEVICE || dm->length < 0x12)
>  		return;
> @@ -405,6 +408,18 @@ static void __init save_mem_devices(const struct dmi_header *dm, void *v)
>  	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]);

<---- newline here.

> +	size = get_unaligned((u16 *)&d[0xC]);
> +	if (size == 0)
> +		bytes = 0;
> +	else if (size == 0xffff)
> +		bytes = ~0ul;
> +	else if (size & 0x8000)
> +		bytes = (u64)(size & 0x7fff) << 10;
> +	else if (size != 0x7fff)
> +		bytes = (u64)size << 20;
> +	else
> +		bytes = (u64)get_unaligned((u32 *)&d[0x1C]) << 20;

<---- newline here.

> +	dmi_memdev[nr].size = bytes;
>  	nr++;
>  }
>  
> @@ -1073,3 +1088,17 @@ void dmi_memdev_name(u16 handle, const char **bank, const char **device)
>  	}
>  }
>  EXPORT_SYMBOL_GPL(dmi_memdev_name);
> +
> +u64 dmi_memdev_size(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].size;
> +		}
> +	}
> +	return ~0ul;
> +}

So dmi_memdev_name() also loops over dmi_memdev and returns bank and
device. This new function returns size.

If code is going to be calling those one after the other, you could do a

	dmi_memdev_desc(u16 handle, struct memdev_desc *desc)

which fills up a descriptor with all fields a caller would need in one
go so that you don't have to iterate multiple times. Looking at struct
dmi_memdev_info, there are no more fields so maybe this is probably
silly though or you can simply return struct dmi_memdev_info directly...

Meh.
Tony Luck Dec. 4, 2017, 10:03 p.m. UTC | #2
On Mon, Dec 04, 2017 at 10:38:14PM +0100, Borislav Petkov wrote:
> On Thu, Nov 30, 2017 at 12:40:40PM -0800, Tony Luck wrote:
> >  	dmi_memdev[nr].bank = dmi_string(dm, d[0x11]);
> 
> <---- newline here.
> 
> > +	size = get_unaligned((u16 *)&d[0xC]);
> > +	if (size == 0)
> > +		bytes = 0;
> > +	else if (size == 0xffff)
> > +		bytes = ~0ul;
> > +	else if (size & 0x8000)
> > +		bytes = (u64)(size & 0x7fff) << 10;
> > +	else if (size != 0x7fff)
> > +		bytes = (u64)size << 20;
> > +	else
> > +		bytes = (u64)get_unaligned((u32 *)&d[0x1C]) << 20;
> 
> <---- newline here.

Ok ... it does read better with those breaks. Will add.

> So dmi_memdev_name() also loops over dmi_memdev and returns bank and
> device. This new function returns size.
> 
> If code is going to be calling those one after the other, you could do a
> 
> 	dmi_memdev_desc(u16 handle, struct memdev_desc *desc)

Current callers are from different code paths (dmi_memdev_name() from
ghes and EFI, dmi_memdev_size() just from the Skylake EDAC driver).
If we later find a place that calls both this would be a good cleanup.

> which fills up a descriptor with all fields a caller would need in one
> go so that you don't have to iterate multiple times. Looking at struct
> dmi_memdev_info, there are no more fields so maybe this is probably
> silly though or you can simply return struct dmi_memdev_info directly...
> 
> Meh.

I take it that you talked yourself out of asking for the cleanup now?

-Tony
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Borislav Petkov Dec. 4, 2017, 10:07 p.m. UTC | #3
On Mon, Dec 04, 2017 at 02:03:16PM -0800, Luck, Tony wrote:
> I take it that you talked yourself out of asking for the cleanup now?

:-)

Nah, it was just a thinking-out-loud thing. Doesn't make sense to do the
cleanup, it seems.
diff mbox

Patch

diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
index 783041964439..946e86fb1ec6 100644
--- a/drivers/firmware/dmi_scan.c
+++ b/drivers/firmware/dmi_scan.c
@@ -37,6 +37,7 @@  static char dmi_ids_string[128] __initdata;
 static struct dmi_memdev_info {
 	const char *device;
 	const char *bank;
+	u64 size;
 	u16 handle;
 } *dmi_memdev;
 static int dmi_memdev_nr;
@@ -395,6 +396,8 @@  static void __init save_mem_devices(const struct dmi_header *dm, void *v)
 {
 	const char *d = (const char *)dm;
 	static int nr;
+	u64 bytes;
+	u16 size;
 
 	if (dm->type != DMI_ENTRY_MEM_DEVICE || dm->length < 0x12)
 		return;
@@ -405,6 +408,18 @@  static void __init save_mem_devices(const struct dmi_header *dm, void *v)
 	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]);
+	size = get_unaligned((u16 *)&d[0xC]);
+	if (size == 0)
+		bytes = 0;
+	else if (size == 0xffff)
+		bytes = ~0ul;
+	else if (size & 0x8000)
+		bytes = (u64)(size & 0x7fff) << 10;
+	else if (size != 0x7fff)
+		bytes = (u64)size << 20;
+	else
+		bytes = (u64)get_unaligned((u32 *)&d[0x1C]) << 20;
+	dmi_memdev[nr].size = bytes;
 	nr++;
 }
 
@@ -1073,3 +1088,17 @@  void dmi_memdev_name(u16 handle, const char **bank, const char **device)
 	}
 }
 EXPORT_SYMBOL_GPL(dmi_memdev_name);
+
+u64 dmi_memdev_size(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].size;
+		}
+	}
+	return ~0ul;
+}
+EXPORT_SYMBOL_GPL(dmi_memdev_size);
diff --git a/include/linux/dmi.h b/include/linux/dmi.h
index 46e151172d95..7f5929123b69 100644
--- a/include/linux/dmi.h
+++ b/include/linux/dmi.h
@@ -113,6 +113,7 @@  extern int dmi_walk(void (*decode)(const struct dmi_header *, void *),
 	void *private_data);
 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);
 
 #else
 
@@ -142,6 +143,7 @@  static inline bool dmi_match(enum dmi_field f, const char *str)
 	{ return false; }
 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 const struct dmi_system_id *
 	dmi_first_match(const struct dmi_system_id *list) { return NULL; }