Change in flashrom[master]: mysteries_intel: Add a section for software vs hardware sequencing
David Hendricks has uploaded this change for review. ( https://review.coreboot.org/c/flashrom/+/42485 ) Change subject: mysteries_intel: Add a section for software vs hardware sequencing ...................................................................... mysteries_intel: Add a section for software vs hardware sequencing This attempts to explain software sequencing, hardware sequencing, and the "Opaque flash chip". Change-Id: I2445e926aad96060f26d0bc55dd7642c1a404296 Signed-off-by: David Hendricks <david.hendricks@gmail.com> --- M Documentation/mysteries_intel.txt 1 file changed, 41 insertions(+), 0 deletions(-) git pull ssh://review.coreboot.org:29418/flashrom refs/changes/85/42485/1 diff --git a/Documentation/mysteries_intel.txt b/Documentation/mysteries_intel.txt index 60ad21a..8ed7b65 100644 --- a/Documentation/mysteries_intel.txt +++ b/Documentation/mysteries_intel.txt @@ -5,6 +5,47 @@ A0h), so we have no clue if or where it is on ICH8. Out current policy is to not touch it at all and assume/hope it is 0. += Software Sequencing vs. Hardware Sequenching and the "Opaque flash chip" = +Software sequencing and hardware sequencing are two methods used to interface +with the SPI controller on Intel platforms. They can be selected using either +ich_spi_mode=swseq and ich_spi_mode=hwseq programmer parameters. Flashrom will +attempt to automatically detect which mode to use. + +Software sequencing is the traditional method whereby software running on the +CPU handles most of the logic needed to interact with the flash chip. This +offers good flexibility since the user can utilize any opcode available in the +OPMENU registers, and OPMENU can be left unlocked or on coreboot-supported +platforms the owner of the system may program it for their needs before locking +it. Advanced or non-standard features of a chip such as write protection and +OTP may be therefore be directly utilized by software. + +Hardware sequencing is a newer method whereby most of the logic for interacting +with the SPI flash chip is contained within the SPI controller itself, and +software such as flashrom may only select a few operations chosen by Intel via +the Flash Cycle (FCYCLE) field. The chip must conform to specifications from +Intel for each chipset/PCH. There specs are given in the "SPI Programming Guide" +for each chipset/PCH and are usually available under NDA. + +Hardware sequencing simplifies things from a software perspective since the +software is guaranteed some minimal level of support and doesn't even need to +know the chip's ID and know its supported opcodes; it just needs to tell the +SPI controller to perform a certain type of transaction such as "read", "4k +block erase", etc. without knowing the actual opcodes used by the chip for the +transaction. Hence when using hardware sequencing one will see "Opaque flash +chip" as the chip's description, since flashrom will not necessarily even read +the chip's ID. This abstraction also allows the SPI controller to do things like +concatenating multiple chips to appear as a single large one. + +In many non-Intel systems the software has full control of a generic SPI +controller where the software controls the chip select and data buffer and also +constructs the payload including pre-op (e.g. write enable latch), opcode, +address, and data. Intel SPI flash controllers are purpose-built for flash chip +access and the software does not control the hardware directly. This makes Intel +SPI controllers less flexible from a software standpoint, however there are some +benefits such as guaranteed atomicity and multi-master arbitration needed for +modern Intel platforms where the CPU and various microprocessors can share the +same flash chip. + = SMM BIOS Write Protection = Sometimes a hardware vendor will enable "SMM BIOS Write Protect" (SMM_BWP) in the firmware during boot time. The bits that control SMM_BWP are in the -- To view, visit https://review.coreboot.org/c/flashrom/+/42485 To unsubscribe, or for help writing mail filters, visit https://review.coreboot.org/settings Gerrit-Project: flashrom Gerrit-Branch: master Gerrit-Change-Id: I2445e926aad96060f26d0bc55dd7642c1a404296 Gerrit-Change-Number: 42485 Gerrit-PatchSet: 1 Gerrit-Owner: David Hendricks <david.hendricks@gmail.com> Gerrit-MessageType: newchange
Hello build bot (Jenkins), I'd like you to reexamine a change. Please visit https://review.coreboot.org/c/flashrom/+/42485 to look at the new patch set (#2). Change subject: mysteries_intel: Add a section for software vs hardware sequencing ...................................................................... mysteries_intel: Add a section for software vs hardware sequencing This attempts to explain software sequencing, hardware sequencing, and the "Opaque flash chip". Change-Id: I2445e926aad96060f26d0bc55dd7642c1a404296 Signed-off-by: David Hendricks <david.hendricks@gmail.com> --- M Documentation/mysteries_intel.txt 1 file changed, 41 insertions(+), 0 deletions(-) git pull ssh://review.coreboot.org:29418/flashrom refs/changes/85/42485/2 -- To view, visit https://review.coreboot.org/c/flashrom/+/42485 To unsubscribe, or for help writing mail filters, visit https://review.coreboot.org/settings Gerrit-Project: flashrom Gerrit-Branch: master Gerrit-Change-Id: I2445e926aad96060f26d0bc55dd7642c1a404296 Gerrit-Change-Number: 42485 Gerrit-PatchSet: 2 Gerrit-Owner: David Hendricks <david.hendricks@gmail.com> Gerrit-Reviewer: build bot (Jenkins) <no-reply@coreboot.org> Gerrit-MessageType: newpatchset
Angel Pons has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/42485 ) Change subject: mysteries_intel: Add a section for software vs hardware sequencing ...................................................................... Patch Set 2: Code-Review+1 (4 comments) https://review.coreboot.org/c/flashrom/+/42485/2/Documentation/mysteries_int... File Documentation/mysteries_intel.txt: https://review.coreboot.org/c/flashrom/+/42485/2/Documentation/mysteries_int... PS2, Line 20: be therefore be duplicated `be` https://review.coreboot.org/c/flashrom/+/42485/2/Documentation/mysteries_int... PS2, Line 26: SPI Programming Guide Reference [SPI_PROG] as an example? https://review.coreboot.org/c/flashrom/+/42485/2/Documentation/mysteries_int... PS2, Line 31: and know nor https://review.coreboot.org/c/flashrom/+/42485/2/Documentation/mysteries_int... PS2, Line 35: will not necessarily even read : the chip's ID note that sometimes we can't do that at all, because there are multiple chips or because some important opcode for swseq is missing and opmenu is locked -- To view, visit https://review.coreboot.org/c/flashrom/+/42485 To unsubscribe, or for help writing mail filters, visit https://review.coreboot.org/settings Gerrit-Project: flashrom Gerrit-Branch: master Gerrit-Change-Id: I2445e926aad96060f26d0bc55dd7642c1a404296 Gerrit-Change-Number: 42485 Gerrit-PatchSet: 2 Gerrit-Owner: David Hendricks <david.hendricks@gmail.com> Gerrit-Reviewer: Angel Pons <th3fanbus@gmail.com> Gerrit-Reviewer: build bot (Jenkins) <no-reply@coreboot.org> Gerrit-CC: Edward O'Callaghan <edward.ocallaghan@koparo.com> Gerrit-CC: Nico Huber <nico.h@gmx.de> Gerrit-Comment-Date: Wed, 17 Jun 2020 22:14:15 +0000 Gerrit-HasComments: Yes Gerrit-Has-Labels: Yes Gerrit-MessageType: comment
Hello build bot (Jenkins), Angel Pons, I'd like you to reexamine a change. Please visit https://review.coreboot.org/c/flashrom/+/42485 to look at the new patch set (#3). Change subject: mysteries_intel: Add a section for software vs hardware sequencing ...................................................................... mysteries_intel: Add a section for software vs hardware sequencing This attempts to explain software sequencing, hardware sequencing, and the "Opaque flash chip". Change-Id: I2445e926aad96060f26d0bc55dd7642c1a404296 Signed-off-by: David Hendricks <david.hendricks@gmail.com> --- M Documentation/mysteries_intel.txt 1 file changed, 42 insertions(+), 0 deletions(-) git pull ssh://review.coreboot.org:29418/flashrom refs/changes/85/42485/3 -- To view, visit https://review.coreboot.org/c/flashrom/+/42485 To unsubscribe, or for help writing mail filters, visit https://review.coreboot.org/settings Gerrit-Project: flashrom Gerrit-Branch: master Gerrit-Change-Id: I2445e926aad96060f26d0bc55dd7642c1a404296 Gerrit-Change-Number: 42485 Gerrit-PatchSet: 3 Gerrit-Owner: David Hendricks <david.hendricks@gmail.com> Gerrit-Reviewer: Angel Pons <th3fanbus@gmail.com> Gerrit-Reviewer: build bot (Jenkins) <no-reply@coreboot.org> Gerrit-CC: Edward O'Callaghan <edward.ocallaghan@koparo.com> Gerrit-CC: Nico Huber <nico.h@gmx.de> Gerrit-MessageType: newpatchset
David Hendricks has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/42485 ) Change subject: mysteries_intel: Add a section for software vs hardware sequencing ...................................................................... Patch Set 3: (4 comments) https://review.coreboot.org/c/flashrom/+/42485/2/Documentation/mysteries_int... File Documentation/mysteries_intel.txt: https://review.coreboot.org/c/flashrom/+/42485/2/Documentation/mysteries_int... PS2, Line 20: be therefore be
duplicated `be` Done
https://review.coreboot.org/c/flashrom/+/42485/2/Documentation/mysteries_int... PS2, Line 26: SPI Programming Guide
Reference [SPI_PROG] as an example? I'm not sure what you mean by [SPI_PROG]... I also may have used confusing terminology. Here I am specifically referring to application notes from Intel that they title "SPI Programming Guide" for each PCH. These are usually referenced from the PCH datasheet, for example in https://www.intel.com/content/www/us/en/products/docs/chipsets/300-series-ch....
I'll try to clarify that. https://review.coreboot.org/c/flashrom/+/42485/2/Documentation/mysteries_int... PS2, Line 31: and know
nor Done
https://review.coreboot.org/c/flashrom/+/42485/2/Documentation/mysteries_int... PS2, Line 35: will not necessarily even read : the chip's ID
note that sometimes we can't do that at all, because there are multiple chips or because some import […] I prefer to avoid mentioning software sequencing in this paragraph since it might be confusing, however I used your example of multiple chips to clarify that we might not even be able to read the chip ID.
-- To view, visit https://review.coreboot.org/c/flashrom/+/42485 To unsubscribe, or for help writing mail filters, visit https://review.coreboot.org/settings Gerrit-Project: flashrom Gerrit-Branch: master Gerrit-Change-Id: I2445e926aad96060f26d0bc55dd7642c1a404296 Gerrit-Change-Number: 42485 Gerrit-PatchSet: 3 Gerrit-Owner: David Hendricks <david.hendricks@gmail.com> Gerrit-Reviewer: Angel Pons <th3fanbus@gmail.com> Gerrit-Reviewer: build bot (Jenkins) <no-reply@coreboot.org> Gerrit-CC: Edward O'Callaghan <edward.ocallaghan@koparo.com> Gerrit-CC: Nico Huber <nico.h@gmx.de> Gerrit-Comment-Date: Thu, 18 Jun 2020 21:19:38 +0000 Gerrit-HasComments: Yes Gerrit-Has-Labels: No Comment-In-Reply-To: Angel Pons <th3fanbus@gmail.com> Gerrit-MessageType: comment
Angel Pons has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/42485 ) Change subject: mysteries_intel: Add a section for software vs hardware sequencing ...................................................................... Patch Set 3: Code-Review+1 (2 comments) https://review.coreboot.org/c/flashrom/+/42485/2/Documentation/mysteries_int... File Documentation/mysteries_intel.txt: https://review.coreboot.org/c/flashrom/+/42485/2/Documentation/mysteries_int... PS2, Line 26: SPI Programming Guide
I'm not sure what you mean by [SPI_PROG]... I also may have used confusing terminology. […] It's at the end of this file:
[SPI_PROG] Ibex Peak SPI Programming Guide Document Number: 403598, Revision 1.3, page 79 https://review.coreboot.org/c/flashrom/+/42485/3/Documentation/mysteries_int... File Documentation/mysteries_intel.txt: https://review.coreboot.org/c/flashrom/+/42485/3/Documentation/mysteries_int... PS3, Line 27: usually referenced from the : chipset/PCH datasheet Uh, not really. AFAIK they come with the ME/TXE kits. -- To view, visit https://review.coreboot.org/c/flashrom/+/42485 To unsubscribe, or for help writing mail filters, visit https://review.coreboot.org/settings Gerrit-Project: flashrom Gerrit-Branch: master Gerrit-Change-Id: I2445e926aad96060f26d0bc55dd7642c1a404296 Gerrit-Change-Number: 42485 Gerrit-PatchSet: 3 Gerrit-Owner: David Hendricks <david.hendricks@gmail.com> Gerrit-Reviewer: Angel Pons <th3fanbus@gmail.com> Gerrit-Reviewer: build bot (Jenkins) <no-reply@coreboot.org> Gerrit-CC: Edward O'Callaghan <edward.ocallaghan@koparo.com> Gerrit-CC: Nico Huber <nico.h@gmx.de> Gerrit-Comment-Date: Thu, 18 Jun 2020 21:30:21 +0000 Gerrit-HasComments: Yes Gerrit-Has-Labels: Yes Comment-In-Reply-To: David Hendricks <david.hendricks@gmail.com> Comment-In-Reply-To: Angel Pons <th3fanbus@gmail.com> Gerrit-MessageType: comment
Angel Pons has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/42485 ) Change subject: mysteries_intel: Add a section for software vs hardware sequencing ...................................................................... Patch Set 3: (1 comment) https://review.coreboot.org/c/flashrom/+/42485/2/Documentation/mysteries_int... File Documentation/mysteries_intel.txt: https://review.coreboot.org/c/flashrom/+/42485/2/Documentation/mysteries_int... PS2, Line 35: will not necessarily even read : the chip's ID
I prefer to avoid mentioning software sequencing in this paragraph since it might be confusing, howe […] Good enough
-- To view, visit https://review.coreboot.org/c/flashrom/+/42485 To unsubscribe, or for help writing mail filters, visit https://review.coreboot.org/settings Gerrit-Project: flashrom Gerrit-Branch: master Gerrit-Change-Id: I2445e926aad96060f26d0bc55dd7642c1a404296 Gerrit-Change-Number: 42485 Gerrit-PatchSet: 3 Gerrit-Owner: David Hendricks <david.hendricks@gmail.com> Gerrit-Reviewer: Angel Pons <th3fanbus@gmail.com> Gerrit-Reviewer: build bot (Jenkins) <no-reply@coreboot.org> Gerrit-CC: Edward O'Callaghan <edward.ocallaghan@koparo.com> Gerrit-CC: Nico Huber <nico.h@gmx.de> Gerrit-Comment-Date: Thu, 18 Jun 2020 21:30:37 +0000 Gerrit-HasComments: Yes Gerrit-Has-Labels: No Comment-In-Reply-To: David Hendricks <david.hendricks@gmail.com> Comment-In-Reply-To: Angel Pons <th3fanbus@gmail.com> Gerrit-MessageType: comment
Hello build bot (Jenkins), Angel Pons, I'd like you to reexamine a change. Please visit https://review.coreboot.org/c/flashrom/+/42485 to look at the new patch set (#4). Change subject: mysteries_intel: Add a section for software vs hardware sequencing ...................................................................... mysteries_intel: Add a section for software vs hardware sequencing This attempts to explain software sequencing, hardware sequencing, and the "Opaque flash chip". Change-Id: I2445e926aad96060f26d0bc55dd7642c1a404296 Signed-off-by: David Hendricks <david.hendricks@gmail.com> --- M Documentation/mysteries_intel.txt 1 file changed, 42 insertions(+), 0 deletions(-) git pull ssh://review.coreboot.org:29418/flashrom refs/changes/85/42485/4 -- To view, visit https://review.coreboot.org/c/flashrom/+/42485 To unsubscribe, or for help writing mail filters, visit https://review.coreboot.org/settings Gerrit-Project: flashrom Gerrit-Branch: master Gerrit-Change-Id: I2445e926aad96060f26d0bc55dd7642c1a404296 Gerrit-Change-Number: 42485 Gerrit-PatchSet: 4 Gerrit-Owner: David Hendricks <david.hendricks@gmail.com> Gerrit-Reviewer: Angel Pons <th3fanbus@gmail.com> Gerrit-Reviewer: build bot (Jenkins) <no-reply@coreboot.org> Gerrit-CC: Edward O'Callaghan <edward.ocallaghan@koparo.com> Gerrit-CC: Nico Huber <nico.h@gmx.de> Gerrit-MessageType: newpatchset
David Hendricks has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/42485 ) Change subject: mysteries_intel: Add a section for software vs hardware sequencing ...................................................................... Patch Set 4: (2 comments) https://review.coreboot.org/c/flashrom/+/42485/2/Documentation/mysteries_int... File Documentation/mysteries_intel.txt: https://review.coreboot.org/c/flashrom/+/42485/2/Documentation/mysteries_int... PS2, Line 26: SPI Programming Guide
It's at the end of this file: […] Thanks!
https://review.coreboot.org/c/flashrom/+/42485/3/Documentation/mysteries_int... File Documentation/mysteries_intel.txt: https://review.coreboot.org/c/flashrom/+/42485/3/Documentation/mysteries_int... PS3, Line 27: usually referenced from the : chipset/PCH datasheet
Uh, not really. AFAIK they come with the ME/TXE kits. I don't think that's true, at least not in my experience searching for SPI programming guides on developer.intel.com.
In any case I think your suggestion of using [SPI_PROG] as an example makes the point. -- To view, visit https://review.coreboot.org/c/flashrom/+/42485 To unsubscribe, or for help writing mail filters, visit https://review.coreboot.org/settings Gerrit-Project: flashrom Gerrit-Branch: master Gerrit-Change-Id: I2445e926aad96060f26d0bc55dd7642c1a404296 Gerrit-Change-Number: 42485 Gerrit-PatchSet: 4 Gerrit-Owner: David Hendricks <david.hendricks@gmail.com> Gerrit-Reviewer: Angel Pons <th3fanbus@gmail.com> Gerrit-Reviewer: build bot (Jenkins) <no-reply@coreboot.org> Gerrit-CC: Edward O'Callaghan <edward.ocallaghan@koparo.com> Gerrit-CC: Nico Huber <nico.h@gmx.de> Gerrit-Comment-Date: Thu, 18 Jun 2020 21:41:26 +0000 Gerrit-HasComments: Yes Gerrit-Has-Labels: No Comment-In-Reply-To: David Hendricks <david.hendricks@gmail.com> Comment-In-Reply-To: Angel Pons <th3fanbus@gmail.com> Gerrit-MessageType: comment
Angel Pons has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/42485 ) Change subject: mysteries_intel: Add a section for software vs hardware sequencing ...................................................................... Patch Set 4: Code-Review+2 (1 comment) https://review.coreboot.org/c/flashrom/+/42485/3/Documentation/mysteries_int... File Documentation/mysteries_intel.txt: https://review.coreboot.org/c/flashrom/+/42485/3/Documentation/mysteries_int... PS3, Line 27: usually referenced from the : chipset/PCH datasheet
I don't think that's true, at least not in my experience searching for SPI programming guides on dev […] Ack
-- To view, visit https://review.coreboot.org/c/flashrom/+/42485 To unsubscribe, or for help writing mail filters, visit https://review.coreboot.org/settings Gerrit-Project: flashrom Gerrit-Branch: master Gerrit-Change-Id: I2445e926aad96060f26d0bc55dd7642c1a404296 Gerrit-Change-Number: 42485 Gerrit-PatchSet: 4 Gerrit-Owner: David Hendricks <david.hendricks@gmail.com> Gerrit-Reviewer: Angel Pons <th3fanbus@gmail.com> Gerrit-Reviewer: build bot (Jenkins) <no-reply@coreboot.org> Gerrit-CC: Edward O'Callaghan <edward.ocallaghan@koparo.com> Gerrit-CC: Nico Huber <nico.h@gmx.de> Gerrit-Comment-Date: Thu, 18 Jun 2020 22:22:33 +0000 Gerrit-HasComments: Yes Gerrit-Has-Labels: Yes Comment-In-Reply-To: David Hendricks <david.hendricks@gmail.com> Comment-In-Reply-To: Angel Pons <th3fanbus@gmail.com> Gerrit-MessageType: comment
Arthur Heymans has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/42485 ) Change subject: mysteries_intel: Add a section for software vs hardware sequencing ...................................................................... Patch Set 4: Code-Review+2 -- To view, visit https://review.coreboot.org/c/flashrom/+/42485 To unsubscribe, or for help writing mail filters, visit https://review.coreboot.org/settings Gerrit-Project: flashrom Gerrit-Branch: master Gerrit-Change-Id: I2445e926aad96060f26d0bc55dd7642c1a404296 Gerrit-Change-Number: 42485 Gerrit-PatchSet: 4 Gerrit-Owner: David Hendricks <david.hendricks@gmail.com> Gerrit-Reviewer: Angel Pons <th3fanbus@gmail.com> Gerrit-Reviewer: Arthur Heymans <arthur@aheymans.xyz> Gerrit-Reviewer: build bot (Jenkins) <no-reply@coreboot.org> Gerrit-CC: Edward O'Callaghan <edward.ocallaghan@koparo.com> Gerrit-CC: Nico Huber <nico.h@gmx.de> Gerrit-Comment-Date: Fri, 19 Jun 2020 05:13:37 +0000 Gerrit-HasComments: No Gerrit-Has-Labels: Yes Gerrit-MessageType: comment
Paul Menzel has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/42485 ) Change subject: mysteries_intel: Add a section for software vs hardware sequencing ...................................................................... Patch Set 4: (1 comment) Thank you for taking the time writing this. https://review.coreboot.org/c/flashrom/+/42485/4/Documentation/mysteries_int... File Documentation/mysteries_intel.txt: https://review.coreboot.org/c/flashrom/+/42485/4/Documentation/mysteries_int... PS4, Line 26: There The? -- To view, visit https://review.coreboot.org/c/flashrom/+/42485 To unsubscribe, or for help writing mail filters, visit https://review.coreboot.org/settings Gerrit-Project: flashrom Gerrit-Branch: master Gerrit-Change-Id: I2445e926aad96060f26d0bc55dd7642c1a404296 Gerrit-Change-Number: 42485 Gerrit-PatchSet: 4 Gerrit-Owner: David Hendricks <david.hendricks@gmail.com> Gerrit-Reviewer: Angel Pons <th3fanbus@gmail.com> Gerrit-Reviewer: Arthur Heymans <arthur@aheymans.xyz> Gerrit-Reviewer: build bot (Jenkins) <no-reply@coreboot.org> Gerrit-CC: Edward O'Callaghan <edward.ocallaghan@koparo.com> Gerrit-CC: Nico Huber <nico.h@gmx.de> Gerrit-CC: Paul Menzel <paulepanter@users.sourceforge.net> Gerrit-Comment-Date: Fri, 19 Jun 2020 08:21:18 +0000 Gerrit-HasComments: Yes Gerrit-Has-Labels: No Gerrit-MessageType: comment
Hello build bot (Jenkins), Angel Pons, Arthur Heymans, I'd like you to reexamine a change. Please visit https://review.coreboot.org/c/flashrom/+/42485 to look at the new patch set (#5). Change subject: mysteries_intel: Add a section for software vs hardware sequencing ...................................................................... mysteries_intel: Add a section for software vs hardware sequencing This attempts to explain software sequencing, hardware sequencing, and the "Opaque flash chip". Change-Id: I2445e926aad96060f26d0bc55dd7642c1a404296 Signed-off-by: David Hendricks <david.hendricks@gmail.com> --- M Documentation/mysteries_intel.txt 1 file changed, 42 insertions(+), 0 deletions(-) git pull ssh://review.coreboot.org:29418/flashrom refs/changes/85/42485/5 -- To view, visit https://review.coreboot.org/c/flashrom/+/42485 To unsubscribe, or for help writing mail filters, visit https://review.coreboot.org/settings Gerrit-Project: flashrom Gerrit-Branch: master Gerrit-Change-Id: I2445e926aad96060f26d0bc55dd7642c1a404296 Gerrit-Change-Number: 42485 Gerrit-PatchSet: 5 Gerrit-Owner: David Hendricks <david.hendricks@gmail.com> Gerrit-Reviewer: Angel Pons <th3fanbus@gmail.com> Gerrit-Reviewer: Arthur Heymans <arthur@aheymans.xyz> Gerrit-Reviewer: build bot (Jenkins) <no-reply@coreboot.org> Gerrit-CC: Edward O'Callaghan <edward.ocallaghan@koparo.com> Gerrit-CC: Nico Huber <nico.h@gmx.de> Gerrit-CC: Paul Menzel <paulepanter@users.sourceforge.net> Gerrit-MessageType: newpatchset
David Hendricks has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/42485 ) Change subject: mysteries_intel: Add a section for software vs hardware sequencing ...................................................................... Patch Set 5: (2 comments) https://review.coreboot.org/c/flashrom/+/42485/4/Documentation/mysteries_int... File Documentation/mysteries_intel.txt: https://review.coreboot.org/c/flashrom/+/42485/4/Documentation/mysteries_int... PS4, Line 10: either removed "either" https://review.coreboot.org/c/flashrom/+/42485/4/Documentation/mysteries_int... PS4, Line 26: There
The? Done
-- To view, visit https://review.coreboot.org/c/flashrom/+/42485 To unsubscribe, or for help writing mail filters, visit https://review.coreboot.org/settings Gerrit-Project: flashrom Gerrit-Branch: master Gerrit-Change-Id: I2445e926aad96060f26d0bc55dd7642c1a404296 Gerrit-Change-Number: 42485 Gerrit-PatchSet: 5 Gerrit-Owner: David Hendricks <david.hendricks@gmail.com> Gerrit-Reviewer: Angel Pons <th3fanbus@gmail.com> Gerrit-Reviewer: Arthur Heymans <arthur@aheymans.xyz> Gerrit-Reviewer: build bot (Jenkins) <no-reply@coreboot.org> Gerrit-CC: Edward O'Callaghan <edward.ocallaghan@koparo.com> Gerrit-CC: Nico Huber <nico.h@gmx.de> Gerrit-CC: Paul Menzel <paulepanter@users.sourceforge.net> Gerrit-Comment-Date: Fri, 19 Jun 2020 15:43:55 +0000 Gerrit-HasComments: Yes Gerrit-Has-Labels: No Comment-In-Reply-To: Paul Menzel <paulepanter@users.sourceforge.net> Gerrit-MessageType: comment
Angel Pons has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/42485 ) Change subject: mysteries_intel: Add a section for software vs hardware sequencing ...................................................................... Patch Set 5: Code-Review+1 (1 comment) Uhm, Jenkins farted it seems. Anyway, here's a suggested change if you want to try retriggering it. https://review.coreboot.org/c/flashrom/+/42485/4/Documentation/mysteries_int... File Documentation/mysteries_intel.txt: https://review.coreboot.org/c/flashrom/+/42485/4/Documentation/mysteries_int... PS4, Line 10: either
removed "either" I would have used "either ... or ..." in this case
-- To view, visit https://review.coreboot.org/c/flashrom/+/42485 To unsubscribe, or for help writing mail filters, visit https://review.coreboot.org/settings Gerrit-Project: flashrom Gerrit-Branch: master Gerrit-Change-Id: I2445e926aad96060f26d0bc55dd7642c1a404296 Gerrit-Change-Number: 42485 Gerrit-PatchSet: 5 Gerrit-Owner: David Hendricks <david.hendricks@gmail.com> Gerrit-Reviewer: Angel Pons <th3fanbus@gmail.com> Gerrit-Reviewer: Arthur Heymans <arthur@aheymans.xyz> Gerrit-Reviewer: build bot (Jenkins) <no-reply@coreboot.org> Gerrit-CC: Edward O'Callaghan <edward.ocallaghan@koparo.com> Gerrit-CC: Nico Huber <nico.h@gmx.de> Gerrit-CC: Paul Menzel <paulepanter@users.sourceforge.net> Gerrit-Comment-Date: Fri, 19 Jun 2020 16:23:07 +0000 Gerrit-HasComments: Yes Gerrit-Has-Labels: Yes Comment-In-Reply-To: David Hendricks <david.hendricks@gmail.com> Gerrit-MessageType: comment
Hello build bot (Jenkins), Angel Pons, Arthur Heymans, I'd like you to reexamine a change. Please visit https://review.coreboot.org/c/flashrom/+/42485 to look at the new patch set (#6). Change subject: mysteries_intel: Add a section for software vs hardware sequencing ...................................................................... mysteries_intel: Add a section for software vs hardware sequencing This attempts to explain software sequencing, hardware sequencing, and the "Opaque flash chip". Change-Id: I2445e926aad96060f26d0bc55dd7642c1a404296 Signed-off-by: David Hendricks <david.hendricks@gmail.com> --- M Documentation/mysteries_intel.txt 1 file changed, 42 insertions(+), 0 deletions(-) git pull ssh://review.coreboot.org:29418/flashrom refs/changes/85/42485/6 -- To view, visit https://review.coreboot.org/c/flashrom/+/42485 To unsubscribe, or for help writing mail filters, visit https://review.coreboot.org/settings Gerrit-Project: flashrom Gerrit-Branch: master Gerrit-Change-Id: I2445e926aad96060f26d0bc55dd7642c1a404296 Gerrit-Change-Number: 42485 Gerrit-PatchSet: 6 Gerrit-Owner: David Hendricks <david.hendricks@gmail.com> Gerrit-Reviewer: Angel Pons <th3fanbus@gmail.com> Gerrit-Reviewer: Arthur Heymans <arthur@aheymans.xyz> Gerrit-Reviewer: build bot (Jenkins) <no-reply@coreboot.org> Gerrit-CC: Edward O'Callaghan <edward.ocallaghan@koparo.com> Gerrit-CC: Nico Huber <nico.h@gmx.de> Gerrit-CC: Paul Menzel <paulepanter@users.sourceforge.net> Gerrit-MessageType: newpatchset
David Hendricks has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/42485 ) Change subject: mysteries_intel: Add a section for software vs hardware sequencing ...................................................................... Patch Set 6: (1 comment) Yay, Jenkins succeeded this time! LMK if there's anything else, or we can just merge it as is. https://review.coreboot.org/c/flashrom/+/42485/4/Documentation/mysteries_int... File Documentation/mysteries_intel.txt: https://review.coreboot.org/c/flashrom/+/42485/4/Documentation/mysteries_int... PS4, Line 10: either
I would have used "either ... or ... […] Done.
-- To view, visit https://review.coreboot.org/c/flashrom/+/42485 To unsubscribe, or for help writing mail filters, visit https://review.coreboot.org/settings Gerrit-Project: flashrom Gerrit-Branch: master Gerrit-Change-Id: I2445e926aad96060f26d0bc55dd7642c1a404296 Gerrit-Change-Number: 42485 Gerrit-PatchSet: 6 Gerrit-Owner: David Hendricks <david.hendricks@gmail.com> Gerrit-Reviewer: Angel Pons <th3fanbus@gmail.com> Gerrit-Reviewer: Arthur Heymans <arthur@aheymans.xyz> Gerrit-Reviewer: build bot (Jenkins) <no-reply@coreboot.org> Gerrit-CC: Edward O'Callaghan <edward.ocallaghan@koparo.com> Gerrit-CC: Nico Huber <nico.h@gmx.de> Gerrit-CC: Paul Menzel <paulepanter@users.sourceforge.net> Gerrit-Comment-Date: Sat, 20 Jun 2020 19:07:25 +0000 Gerrit-HasComments: Yes Gerrit-Has-Labels: No Comment-In-Reply-To: David Hendricks <david.hendricks@gmail.com> Comment-In-Reply-To: Angel Pons <th3fanbus@gmail.com> Gerrit-MessageType: comment
Angel Pons has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/42485 ) Change subject: mysteries_intel: Add a section for software vs hardware sequencing ...................................................................... Patch Set 6: Code-Review+2 -- To view, visit https://review.coreboot.org/c/flashrom/+/42485 To unsubscribe, or for help writing mail filters, visit https://review.coreboot.org/settings Gerrit-Project: flashrom Gerrit-Branch: master Gerrit-Change-Id: I2445e926aad96060f26d0bc55dd7642c1a404296 Gerrit-Change-Number: 42485 Gerrit-PatchSet: 6 Gerrit-Owner: David Hendricks <david.hendricks@gmail.com> Gerrit-Reviewer: Angel Pons <th3fanbus@gmail.com> Gerrit-Reviewer: Arthur Heymans <arthur@aheymans.xyz> Gerrit-Reviewer: build bot (Jenkins) <no-reply@coreboot.org> Gerrit-CC: Edward O'Callaghan <edward.ocallaghan@koparo.com> Gerrit-CC: Nico Huber <nico.h@gmx.de> Gerrit-CC: Paul Menzel <paulepanter@users.sourceforge.net> Gerrit-Comment-Date: Sat, 20 Jun 2020 20:10:33 +0000 Gerrit-HasComments: No Gerrit-Has-Labels: Yes Gerrit-MessageType: comment
Angel Pons has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/42485 ) Change subject: mysteries_intel: Add a section for software vs hardware sequencing ...................................................................... Patch Set 6:
Patch Set 6:
(1 comment)
Yay, Jenkins succeeded this time! LMK if there's anything else, or we can just merge it as is.
LGTM, I'll submit it. -- To view, visit https://review.coreboot.org/c/flashrom/+/42485 To unsubscribe, or for help writing mail filters, visit https://review.coreboot.org/settings Gerrit-Project: flashrom Gerrit-Branch: master Gerrit-Change-Id: I2445e926aad96060f26d0bc55dd7642c1a404296 Gerrit-Change-Number: 42485 Gerrit-PatchSet: 6 Gerrit-Owner: David Hendricks <david.hendricks@gmail.com> Gerrit-Reviewer: Angel Pons <th3fanbus@gmail.com> Gerrit-Reviewer: Arthur Heymans <arthur@aheymans.xyz> Gerrit-Reviewer: build bot (Jenkins) <no-reply@coreboot.org> Gerrit-CC: Edward O'Callaghan <edward.ocallaghan@koparo.com> Gerrit-CC: Nico Huber <nico.h@gmx.de> Gerrit-CC: Paul Menzel <paulepanter@users.sourceforge.net> Gerrit-Comment-Date: Sat, 20 Jun 2020 20:10:57 +0000 Gerrit-HasComments: No Gerrit-Has-Labels: No Gerrit-MessageType: comment
Angel Pons has submitted this change. ( https://review.coreboot.org/c/flashrom/+/42485 ) Change subject: mysteries_intel: Add a section for software vs hardware sequencing ...................................................................... mysteries_intel: Add a section for software vs hardware sequencing This attempts to explain software sequencing, hardware sequencing, and the "Opaque flash chip". Change-Id: I2445e926aad96060f26d0bc55dd7642c1a404296 Signed-off-by: David Hendricks <david.hendricks@gmail.com> Reviewed-on: https://review.coreboot.org/c/flashrom/+/42485 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Angel Pons <th3fanbus@gmail.com> --- M Documentation/mysteries_intel.txt 1 file changed, 42 insertions(+), 0 deletions(-) Approvals: build bot (Jenkins): Verified Angel Pons: Looks good to me, approved diff --git a/Documentation/mysteries_intel.txt b/Documentation/mysteries_intel.txt index 60ad21a..088abb8 100644 --- a/Documentation/mysteries_intel.txt +++ b/Documentation/mysteries_intel.txt @@ -5,6 +5,48 @@ A0h), so we have no clue if or where it is on ICH8. Out current policy is to not touch it at all and assume/hope it is 0. += Software Sequencing vs. Hardware Sequencing and the "Opaque flash chip" = +Software sequencing and hardware sequencing are two methods used to interface +with the SPI controller on Intel platforms. They can be selected using either +ich_spi_mode=swseq or ich_spi_mode=hwseq programmer parameters. Flashrom will +attempt to automatically detect which mode to use. + +Software sequencing is the traditional method whereby software running on the +CPU handles most of the logic needed to interact with the flash chip. This +offers good flexibility since the user can utilize any opcode available in the +OPMENU registers, and OPMENU can be left unlocked or on coreboot-supported +platforms the owner of the system may program it for their needs before locking +it. Advanced or non-standard features of a chip such as write protection and +OTP may therefore be directly utilized by software. + +Hardware sequencing is a newer method (since around 2011) whereby most of the +logic for interacting with the SPI flash chip is contained within the SPI +controller itself and software such as flashrom may only select a few operations +chosen by Intel via the Flash Cycle (FCYCLE) field. The chip must conform to +specifications from Intel for each chipset/PCH. The specs are given in the +"SPI Programming Guide" application note. See [SPI_PROG] cited at the bottom of +this document for an example. + +Hardware sequencing simplifies things from a software perspective since the +software is guaranteed some minimal level of support and doesn't even need to +know the chip's ID or opcodes; it just needs to tell the SPI controller to +perform a type of transaction such as "read", "4k block erase", etc. Hence when +using hardware sequencing one will see "Opaque flash chip" as the chip's +description since software might not be able to identify the chip. The SPI +controller can combine multiple physical flash chips to logically appear as a +single large flash device, and in such cases it would not make sense for +flashrom to try to identify the chip. + +In many non-Intel systems the software has full control of a generic SPI +controller where the software controls the SPI signals and also constructs the +data payload including pre-op (e.g. write enable latch), opcode, address, and +data. Intel SPI flash controllers are purpose-built for flash chip access and +the software does not control the hardware directly. This makes Intel SPI +controllers less flexible from a software standpoint, however there are some +benefits such as guaranteed atomicity and multi-master arbitration needed for +modern Intel platforms where the CPU and various microprocessors can share the +same flash chip. + = SMM BIOS Write Protection = Sometimes a hardware vendor will enable "SMM BIOS Write Protect" (SMM_BWP) in the firmware during boot time. The bits that control SMM_BWP are in the -- To view, visit https://review.coreboot.org/c/flashrom/+/42485 To unsubscribe, or for help writing mail filters, visit https://review.coreboot.org/settings Gerrit-Project: flashrom Gerrit-Branch: master Gerrit-Change-Id: I2445e926aad96060f26d0bc55dd7642c1a404296 Gerrit-Change-Number: 42485 Gerrit-PatchSet: 7 Gerrit-Owner: David Hendricks <david.hendricks@gmail.com> Gerrit-Reviewer: Angel Pons <th3fanbus@gmail.com> Gerrit-Reviewer: Arthur Heymans <arthur@aheymans.xyz> Gerrit-Reviewer: build bot (Jenkins) <no-reply@coreboot.org> Gerrit-CC: Edward O'Callaghan <edward.ocallaghan@koparo.com> Gerrit-CC: Nico Huber <nico.h@gmx.de> Gerrit-CC: Paul Menzel <paulepanter@users.sourceforge.net> Gerrit-MessageType: merged
participants (4)
-
Angel Pons (Code Review) -
Arthur Heymans (Code Review)
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David Hendricks (Code Review)
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Paul Menzel (Code Review)