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net/xgene: fix error handling during reset

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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 <arnd@arndb.de>
Fixes: 3eb7cb9dc9 ("drivers: net: xgene: XFI PCS reset when link is down")
Cc: Fushen Chen <fchen@apm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Arnd Bergmann 2016-08-26 17:25:46 +02:00 committed by David S. Miller
parent 5711a98221
commit f9dc70744d
1 changed files with 9 additions and 3 deletions
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12
drivers/net/ethernet/apm/xgene/xgene_enet_xgmac.c
View file

@ -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);
}