pldm: Add support for reading file data from remote PDR

Add the pldm-platform crate, and query the PDR for the file identifier
and size.

We expect the file PDR as entry 1.

Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>

Author: jk-ozlabs

CHANGELOG.md

@@ -11,7 +11,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 1. Added support for NVMe-MI responder, gated on a new `nvme-mi` cargo feature
 
 2. Added support for a PLDM for File Transfer requester, triggered on MCTP
-   address assignment.
+   address assignment. This performs a PLDM PDR query to retrieve the
+   File Identifier to transfer.
 
 ### Changed
 

Cargo.lock

@@ -9,7 +9,7 @@ categories = ["network-programming", "hardware-support"]
 
 [features]
 nvme-mi = ["dep:nvme-mi-dev"]
-pldm = ["dep:pldm", "dep:pldm-file"]
+pldm = ["dep:pldm", "dep:pldm-file", "dep:pldm-platform"]
 
 [dependencies]
 anyhow = "1.0.86"
@@ -29,6 +29,7 @@ nvme-mi-dev = { git = "https://github.com/CodeConstruct/nvme-mi-dev", branch = "
 polling = "3.7.4"
 pldm = { git = "https://github.com/CodeConstruct/mctp-rs", rev = "851360ed19ef78f2e7672daa90900cb4f38ad0b6", package = "pldm", optional = true }
 pldm-file = { git = "https://github.com/CodeConstruct/mctp-rs", rev = "851360ed19ef78f2e7672daa90900cb4f38ad0b6", package = "pldm-file", optional = true }
+pldm-platform = { git = "https://github.com/CodeConstruct/mctp-rs", rev = "851360ed19ef78f2e7672daa90900cb4f38ad0b6", package = "pldm-platform", optional = true }
 simplelog = "0.12.2"
 smol = "2.0.0"
 usbredirparser = { git = "https://github.com/CodeConstruct/usbredir-rs", branch = "main", package = "usbredirparser" }

Cargo.toml

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-3.0
 
-use anyhow::{Context, Result};
+use anyhow::{bail, Context, Result};
 use log::{debug, info, warn};
 
 use mctp_estack::{control::ControlEvent, router::Router};
@@ -9,6 +9,7 @@ use pldm_file::{
     client::{df_close, df_open, df_read_with},
     proto::{DfCloseAttributes, DfOpenAttributes, FileIdentifier},
 };
+use pldm_platform::{proto::PdrRecord, requester as platrq};
 
 async fn pldm_control(chan: &mut impl mctp::AsyncReqChannel) -> Result<()> {
     let req_types = [pldm_file::PLDM_TYPE_FILE_TRANSFER];
@@ -25,27 +26,53 @@ async fn pldm_control(chan: &mut impl mctp::AsyncReqChannel) -> Result<()> {
 }
 
 async fn pldm_pdr(
-    mut _chan: &mut impl mctp::AsyncReqChannel,
+    chan: &mut impl mctp::AsyncReqChannel,
 ) -> Result<(FileIdentifier, usize)> {
-    Ok((FileIdentifier(0), 4096))
+    // PDR Repository Info
+    let pdr_info = platrq::get_pdr_repository_info(chan)
+        .await
+        .context("Get PDR Repository Info failed")?;
+
+    debug!("PDR Repository Info: {pdr_info:?}");
+
+    // File Descriptor PDR
+    let pdr_record = 1;
+    let pdr = platrq::get_pdr(chan, pdr_record)
+        .await
+        .context("Get PDR failed")?;
+
+    let PdrRecord::FileDescriptor(file) = pdr else {
+        bail!("Unexpected PDR record {pdr_record}: {pdr:?}");
+    };
+
+    debug!("PDR: {file:?}");
+
+    Ok((
+        FileIdentifier(file.file_identifier),
+        file.file_max_size as usize,
+    ))
 }
 
 async fn pldm_file(
     chan: &mut impl mctp::AsyncReqChannel,
     file: FileIdentifier,
-    _size: usize,
+    size: usize,
 ) -> Result<()> {
     let attrs = DfOpenAttributes::empty();
     let fd = df_open(chan, file, attrs).await.context("DfOpen failed")?;
 
     debug!("Open: {fd:?}");
 
     let mut buf = Vec::new();
-    let req_len = 4096;
+    let req_len = size;
 
     debug!("Reading...");
     let res = df_read_with(chan, fd, 0, req_len, |part| {
-        debug!("  {} bytes", part.len());
+        debug!(
+            "  {} bytes, {}/{req_len}",
+            part.len(),
+            buf.len() + part.len()
+        );
         if buf.len() + part.len() > req_len {
             warn!("  data overflow!");
             Err(PldmError::NoSpace)