From f9dc70744dc74bc9e128d579f2bc85eb7c0ad8ce Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Fri, 26 Aug 2016 17:25:46 +0200 Subject: net/xgene: fix error handling during reset The newly added reset logic uses helper functions for the MMIO that may fail. However, when the read operation fails, we end up writing back uninitialized data to the register, as gcc warns: drivers/net/ethernet/apm/xgene/xgene_enet_xgmac.c: In function 'xgene_enet_link_state': drivers/net/ethernet/apm/xgene/xgene_enet_xgmac.c:213:2: error: 'data' may be used uninitialized in this function [-Werror=maybe-uninitialized] drivers/net/ethernet/apm/xgene/xgene_enet_xgmac.c:209:6: note: 'data' was declared here u32 data; We already print a warning to the console log if that happens, the best alternative that I can see is skip the rest of the reset sequence if the register value cannot be read: Most likely the write would fail as well, and if it succeeded, worse things could happen. Signed-off-by: Arnd Bergmann Fixes: 3eb7cb9dc946 ("drivers: net: xgene: XFI PCS reset when link is down") Cc: Fushen Chen Signed-off-by: David S. Miller diff --git a/drivers/net/ethernet/apm/xgene/xgene_enet_xgmac.c b/drivers/net/ethernet/apm/xgene/xgene_enet_xgmac.c index d672e71..279ee27 100644 --- a/drivers/net/ethernet/apm/xgene/xgene_enet_xgmac.c +++ b/drivers/net/ethernet/apm/xgene/xgene_enet_xgmac.c @@ -155,19 +155,23 @@ static void xgene_enet_rd_mac(struct xgene_enet_pdata *pdata, rd_addr); } -static void xgene_enet_rd_pcs(struct xgene_enet_pdata *pdata, +static bool xgene_enet_rd_pcs(struct xgene_enet_pdata *pdata, u32 rd_addr, u32 *rd_data) { void __iomem *addr, *rd, *cmd, *cmd_done; + bool success; addr = pdata->pcs_addr + PCS_ADDR_REG_OFFSET; rd = pdata->pcs_addr + PCS_READ_REG_OFFSET; cmd = pdata->pcs_addr + PCS_COMMAND_REG_OFFSET; cmd_done = pdata->pcs_addr + PCS_COMMAND_DONE_REG_OFFSET; - if (!xgene_enet_rd_indirect(addr, rd, cmd, cmd_done, rd_addr, rd_data)) + success = xgene_enet_rd_indirect(addr, rd, cmd, cmd_done, rd_addr, rd_data); + if (!success) netdev_err(pdata->ndev, "PCS read failed, addr: %04x\n", rd_addr); + + return success; } static int xgene_enet_ecc_init(struct xgene_enet_pdata *pdata) @@ -208,7 +212,9 @@ static void xgene_pcs_reset(struct xgene_enet_pdata *pdata) { u32 data; - xgene_enet_rd_pcs(pdata, PCS_CONTROL_1, &data); + if (!xgene_enet_rd_pcs(pdata, PCS_CONTROL_1, &data)) + return; + xgene_enet_wr_pcs(pdata, PCS_CONTROL_1, data | PCS_CTRL_PCS_RST); xgene_enet_wr_pcs(pdata, PCS_CONTROL_1, data & ~PCS_CTRL_PCS_RST); } -- cgit v0.10.2