> -----Original Message----- > From: Toshi Kani [mailto:toshi.kani@xxxxxxx] > Sent: Tuesday, March 01, 2016 9:37 AM > To: Moore, Robert; rjw@xxxxxxxxxxxxx; Williams, Dan J > Cc: Zheng, Lv; elliott@xxxxxxx; linux-nvdimm@xxxxxxxxxxxx; linux- > acpi@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; devel@xxxxxxxxxx > Subject: Re: [PATCH v2 1/3] ACPI/NFIT: Update Control Region Structure to > comply ACPI 6.1 > > On Tue, 2016-03-01 at 16:03 +0000, Moore, Robert wrote: > > We have a bunch of macros in include/acmacros.h -- like this: > > > > ACPI_MOVE_16_TO_16(d, s) > > There is a problem in using the ACPICA byte-swap macros. ACPI is little- > endian arch, so the macros are set to perform byte-swappings when the CPU > arch is big-endian. This case, however, is the other way around. The > fields in question are defined & stored as arrays of bytes. That's not what I see in the ACPI spec. The fields are defined like any other ACPI table. Vendor ID 2 6 Identifier indicating the vendor of the NVDIMM. This field shall be set to the value of the NVDIMM SPD Module Manufacturer ID Code field a with byte 0 set to DDR4 SPD byte 320 and byte 1 set to DDR4 SPD byte 321. Device ID 2 8 Identifier for the NVDIMM, assigned by the module vendor. This field shall be set to the value of the NVDIMM SPD Module Product Identifier field b with byte 0 set to SPD byte 192 and byte 1 set to SPD byte 193. Revision ID 2 10 Revision of the NVDIMM, assigned by the module vendor. Byte 1 of this field is reserved. Byte 0 of this field shall be set to the value of the NVDIMM SPD Module Revision Code field a (i.e., SPD byte 349). Etc. If you treat > them as multi-bytes numeric values, then you need to byte-swap them when > the CPU arch is little-endian because arrays of bytes have the same > addressing as big-endian. > > Another issue is that it is not clear who needs to perform the byte- > swapping among ACPICA and drivers. If ACPICA, drivers must agree that > these fields are always treated as multi-bytes numeric values despite of > the spec. If drivers, we need to make sure that only a single driver > performs this byte-swapping one time as ACPI tables are global structures. > > I think it is much clearer to define the structure according to the ACPI > spec. > > Thanks, > -Toshi > > > > -----Original Message----- > > > From: Toshi Kani [mailto:toshi.kani@xxxxxxx] > > > Sent: Tuesday, March 01, 2016 8:38 AM > > > To: Moore, Robert; rjw@xxxxxxxxxxxxx; Williams, Dan J > > > Cc: Zheng, Lv; elliott@xxxxxxx; linux-nvdimm@xxxxxxxxxxxx; linux- > > > acpi@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; devel@xxxxxxxxxx > > > Subject: Re: [PATCH v2 1/3] ACPI/NFIT: Update Control Region > > > Structure to comply ACPI 6.1 > > > > > > On Tue, 2016-03-01 at 15:13 +0000, Moore, Robert wrote: > > > > > > > > > -----Original Message----- > > > > > From: Toshi Kani [mailto:toshi.kani@xxxxxxx] > > > > > Sent: Monday, February 22, 2016 1:55 PM > > > > > To: rjw@xxxxxxxxxxxxx; Williams, Dan J > > > > > Cc: Moore, Robert; Zheng, Lv; elliott@xxxxxxx; > > > > > linux-nvdimm@xxxxxxxxxxx g; linux-acpi@xxxxxxxxxxxxxxx; > > > > > linux-kernel@xxxxxxxxxxxxxxx; devel@xxxxxxxxxx; Toshi Kani > > > > > Subject: [PATCH v2 1/3] ACPI/NFIT: Update Control Region > > > > > Structure to comply ACPI 6.1 > > > > > > > > > > ACPI 6.1, Table 5-133, updates NVDIMM Control Region Structure > > > > > as follows. > > > > > - Valid Fields, Manufacturing Location, and Manufacturing Date > > > > > are added from reserved range. No change in the structure > size. > > > > > - IDs defined as SPD values are arrays of bytes. The spec > > > > > clarified that they need to be represented as arrays of bytes > > > > > as well. > > > > > > > > > > This patch makes the following changes to support this update. > > > > > - Change 'struct acpi_nfit_control_region' to reflect the update. > > > > > SPD IDs are defined as arrays of bytes, so that they can be > > > > > treated in the same way regardless of CPU endianness and are > > > > > not miss-treated as little-endian numeric values. > > > > > > > > > > > > I don't think we are going to start changing the ACPI tables > > > > defined in the ACPICA headers because of this. We do in fact have > > > > macros for this purpose. > > > > > > Can you elaborate what macros you suggest to use for this purpose? > > > > > > Thanks, > > > -Toshi > > N r y b X ǧv ^ ){.n + { i b {ay ʇڙ ,j f h z w > > > > j:+v w j m zZ+ ݢj" ! i ��.n��������+%������w��{.n�����{�����ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f
