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authorFurquan Shaikh <furquan@google.com>2021-01-15 17:12:12 -0800
committerPatrick Georgi <pgeorgi@google.com>2021-01-25 08:48:38 +0000
commit859ca18ced83ed3b8b529112da5f214ede3d38b0 (patch)
tree442530c9f30c04b1792731414587852aa76a8c5e /src/mainboard/google/gru
parent99157c1f4a80556462ca22a4ade87b2c8d09e674 (diff)
soc/intel/common: Add support for populating meminit data
This change adds support for a common block memory driver that can be used for performing the required operations to read SPD data for different memory channel DIMMs. This data can then be used by the SoC code to populate different memory related UPDs. Most recent Intel platforms follow a similar pattern for configuring FSP-M UPDs for initializing memory. These platforms use one of the following topologies: 1. Memory down 2. DIMM modules 3. Mixed Thus, SPD data is either obtained from CBFS (for memory down topology) or from on-module EEPROM (for DIMM modules). This SPD data read from CBFS or EEPROM is then passed into FSP-M using SPD UPDs for different channels/DIMMs as per the memory organization. Similarly, DQ/DQS configuration is accepted from mainboard and passed into FSP-M using UPDs as per the FSP-M/MRC organization of memory channels. Different memory technologies on a platform support physical channels of different widths. Since the data bus width is fixed for a platform, the number of physical channels is determined by data bus width / physical channel width. The number of physical channels are different depending upon the size of physical channel supported by the memory technology. FSP-M for a platform uses the same set of UPDs for different memory technologies and aims at providing maximum flexibility. Thus, the platform code needs to format mainboard inputs for DQ, DQS and SPD into the UPDs appropriately as per the memory technology used by the board. Example: DDR4 on TGL supports 2 physical channels each 64-bit wide. However, FSP-M UPDs assume channels 16-bit wide. Thus, FSP-M provides 16 UPDs for SPDs (considering 2 DIMMs per channel and 8 channels with each channel 16-bit wide). Hence, for DDR4, only the SPD UPDs for MRC channel 0 and 4 are supposed to be used. This common driver allows the SoC to define the attributes of the platform: 1. DIMMS_PER_CHANNEL: Maximum DIMMs that are supported per channel by any memory technology on the platform 2. DATA_BUS_WIDTH: Width of the data bus. 3. MRC_CHANNEL_WIDTH: Width of the channel as used by the MRC to define UPDs. In addition to this, the SoC can define different attributes of each memory technology supported by the platform using `struct soc_mem_cfg`: 1. Number of physical channels 2. Physical channel to MRC channel mapping 3. Masks for memory down topologies Using the above information about different memory technologies supported by the platform and the mainboard configuration for SPD, the common block memory driver reads SPD data and provides pointers to this data for each dimm within each channel back to the SoC code. SoC code can then use this information to configure FSP-M UPDs accordingly. In addition to that, the common block driver also returns information about how the channels are populated so that the SoC code can use this information to expose DQ/DQS information in FSP-M UPDs. This driver aims at minimizing the effort required for supporting different memory technologies on any new Intel SoC by reducing per-SoC effort to a table of configurations rather than having to implement similar logic for each SoC. BUG=b:172978729 Change-Id: I256747f0ffc49fb326cd8bc54a6a7b493af139c0 Signed-off-by: Furquan Shaikh <furquan@google.com> Reviewed-on: https://review.coreboot.org/c/coreboot/+/49040 Reviewed-by: Angel Pons <th3fanbus@gmail.com> Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org> Reviewed-by: EricR Lai <ericr_lai@compal.corp-partner.google.com> Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Diffstat (limited to 'src/mainboard/google/gru')
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