From: Ira Weiny <ira.weiny@xxxxxxxxx> The CDAT read may fail for a number of reasons but mainly it is possible to get different parts of a valid state. The checksum in the CDAT table protects against this. Now that the cdat data is validated, issue a retry if the CDAT read fails. For now 5 retries are implemented. Reviewed-by: Ben Widawsky <bwidawsk@xxxxxxxxxx> Reviewed-by: Alison Schofield <alison.schofield@xxxxxxxxx> Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx> --- Changes from V12 Jonathan: Standardize on 'rc' for return code Don't set rc unnecessarily Changes from V10 Pick up review tag and fix commit message Changes from V9 Alison Schofield/Davidlohr Bueso Print debug on each iteration and error only after failure Changes from V8 Move code to cxl/core/pci.c Changes from V6 Move to pci.c Fix retries count Change to 5 retries Changes from V5: New patch -- easy to push off or drop. --- drivers/cxl/core/pci.c | 39 +++++++++++++++++++++++++++++---------- 1 file changed, 29 insertions(+), 10 deletions(-) diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c index 0a1620c302e1..0853885c5767 100644 --- a/drivers/cxl/core/pci.c +++ b/drivers/cxl/core/pci.c @@ -623,13 +623,7 @@ static int cxl_cdat_read_table(struct device *dev, return 0; } -/** - * read_cdat_data - Read the CDAT data on this port - * @port: Port to read data from - * - * This call will sleep waiting for responses from the DOE mailbox. - */ -void read_cdat_data(struct cxl_port *port) +static int __read_cdat_data(struct cxl_port *port) { static struct pci_doe_mb *cdat_mb; struct device *dev = &port->dev; @@ -640,19 +634,19 @@ void read_cdat_data(struct cxl_port *port) cdat_mb = find_cdat_mb(uport); if (!cdat_mb) { dev_dbg(dev, "No CDAT mailbox\n"); - return; + return -EIO; } port->cdat_sup = true; if (cxl_cdat_get_length(dev, cdat_mb, &cdat_length)) { dev_dbg(dev, "No CDAT length\n"); - return; + return -EIO; } port->cdat.table = devm_kzalloc(dev, cdat_length, GFP_KERNEL); if (!port->cdat.table) - return; + return -ENOMEM; port->cdat.length = cdat_length; rc = cxl_cdat_read_table(dev, cdat_mb, &port->cdat); @@ -663,5 +657,30 @@ void read_cdat_data(struct cxl_port *port) port->cdat.length = 0; dev_err(dev, "CDAT data read error\n"); } + + return rc; +} + +/** + * read_cdat_data - Read the CDAT data on this port + * @port: Port to read data from + * + * This call will sleep waiting for responses from the DOE mailbox. + */ +void read_cdat_data(struct cxl_port *port) +{ + int retries = 5; + int rc; + + while (retries--) { + rc = __read_cdat_data(port); + if (!rc) + return; + dev_dbg(&port->dev, + "CDAT data read error rc=%d (retries %d)\n", + rc, retries); + } + dev_err(&port->dev, "CDAT data read failed after %d retries\n", + retries); } EXPORT_SYMBOL_NS_GPL(read_cdat_data, CXL); -- 2.35.3