From e17813968b08b1b09bf80699223dea48851cbd07 Mon Sep 17 00:00:00 2001 From: =?utf8?q?=C3=81lvaro=20Fern=C3=A1ndez=20Rojas?= Date: Sat, 14 Jun 2025 09:59:56 +0200 Subject: [PATCH] net: dsa: b53: prevent BRCM_HDR access on older devices MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 --- drivers/net/dsa/b53/b53_common.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/net/dsa/b53/b53_common.c b/drivers/net/dsa/b53/b53_common.c index daf7c19067114..2bcbb003b1fd6 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) -- 2.47.2