From: Álvaro Fernández Rojas Date: Sat, 14 Jun 2025 07:59:56 +0000 (+0200) Subject: net: dsa: b53: prevent BRCM_HDR access on older devices X-Git-Tag: io_uring-6.17-20250815~128^2~373^2~4 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=e17813968b08b1b09bf80699223dea48851cbd07;p=linux-block.git net: dsa: b53: prevent BRCM_HDR access on older devices Older switches don't implement BRCM_HDR register so we should avoid reading or writing it. Reviewed-by: Florian Fainelli Signed-off-by: Álvaro Fernández Rojas Link: https://patch.msgid.link/20250614080000.1884236-11-noltari@gmail.com Signed-off-by: Jakub Kicinski --- diff --git a/drivers/net/dsa/b53/b53_common.c b/drivers/net/dsa/b53/b53_common.c index daf7c1906711..2bcbb003b1fd 100644 --- a/drivers/net/dsa/b53/b53_common.c +++ b/drivers/net/dsa/b53/b53_common.c @@ -730,6 +730,11 @@ void b53_brcm_hdr_setup(struct dsa_switch *ds, int port) hdr_ctl |= GC_FRM_MGMT_PORT_M; b53_write8(dev, B53_MGMT_PAGE, B53_GLOBAL_CONFIG, hdr_ctl); + /* B53_BRCM_HDR not present on devices with legacy tags */ + if (dev->tag_protocol == DSA_TAG_PROTO_BRCM_LEGACY || + dev->tag_protocol == DSA_TAG_PROTO_BRCM_LEGACY_FCS) + return; + /* Enable Broadcom tags for IMP port */ b53_read8(dev, B53_MGMT_PAGE, B53_BRCM_HDR, &hdr_ctl); if (tag_en)