Commit e9a9970b authored by Russ Weight's avatar Russ Weight Committed by Moritz Fischer
Browse files

fpga: dfl: Avoid reads to AFU CSRs during enumeration 



CSR address space for Accelerator Functional Units (AFU) is not available
during the early Device Feature List (DFL) enumeration. Early access
to this space results in invalid data and port errors. This change adds
a condition to prevent an early read from the AFU CSR space.

Fixes: 1604986c ("fpga: dfl: expose feature revision from struct dfl_device")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarRuss Weight <russell.h.weight@intel.com>
Signed-off-by: default avatarMoritz Fischer <mdf@kernel.org>
parent a1e44708

drivers/fpga/dfl.c

+8 −6
Original line number Diff line number Diff line
@@ -1019,16 +1019,18 @@ create_feature_instance(struct build_feature_devs_info *binfo, 
{

	unsigned int irq_base, nr_irqs;

	struct dfl_feature_info *finfo;

	u8 revision = 0;

	int ret;

	u8 revision;

	u64 v;



	if (fid != FEATURE_ID_AFU) {

		v = readq(binfo->ioaddr + ofst);

		revision = FIELD_GET(DFH_REVISION, v);



		/* read feature size and id if inputs are invalid */

		size = size ? size : feature_size(v);

		fid = fid ? fid : feature_id(v);

	}



	if (binfo->len - ofst < size)

		return -EINVAL;