From: Eric Dumazet <edumazet@google.com>
Date: Sat, 23 May 2020 12:46:49 -0700
Subject: bnx2x: allow bnx2x_bsc_read() to schedule
Patch-mainline: v5.8-rc1
Git-commit: 880f8f99d12ca89d3ec76f688e0d92612054cbb1
References: jsc#SLE-13628
bnx2x_warpcore_read_sfp_module_eeprom() can call bnx2x_bsc_read()
three times before giving up.
This causes latency blips of at least 31 ms (58 ms being reported
by our teams)
Convert the long lasting loops of udelay() to usleep_range() ones,
and breaks the loops on precise time tracking.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Ariel Elior <aelior@marvell.com>
Cc: Sudarsana Kalluru <skalluru@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
drivers/net/ethernet/broadcom/bnx2x/bnx2x_link.c | 26 +++++++++++++----------
1 file changed, 15 insertions(+), 11 deletions(-)
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_link.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_link.c
@@ -3085,6 +3085,7 @@ static int bnx2x_bsc_read(struct link_pa
u8 xfer_cnt,
u32 *data_array)
{
+ u64 t0, delta;
u32 val, i;
int rc = 0;
@@ -3114,17 +3115,18 @@ static int bnx2x_bsc_read(struct link_pa
REG_WR(bp, MCP_REG_MCPR_IMC_COMMAND, val);
/* Poll for completion */
- i = 0;
+ t0 = ktime_get_ns();
val = REG_RD(bp, MCP_REG_MCPR_IMC_COMMAND);
while (((val >> MCPR_IMC_COMMAND_IMC_STATUS_BITSHIFT) & 0x3) != 1) {
- udelay(10);
- val = REG_RD(bp, MCP_REG_MCPR_IMC_COMMAND);
- if (i++ > 1000) {
- DP(NETIF_MSG_LINK, "wr 0 byte timed out after %d try\n",
- i);
+ delta = ktime_get_ns() - t0;
+ if (delta > 10 * NSEC_PER_MSEC) {
+ DP(NETIF_MSG_LINK, "wr 0 byte timed out after %Lu ns\n",
+ delta);
rc = -EFAULT;
break;
}
+ usleep_range(10, 20);
+ val = REG_RD(bp, MCP_REG_MCPR_IMC_COMMAND);
}
if (rc == -EFAULT)
return rc;
@@ -3138,16 +3140,18 @@ static int bnx2x_bsc_read(struct link_pa
REG_WR(bp, MCP_REG_MCPR_IMC_COMMAND, val);
/* Poll for completion */
- i = 0;
+ t0 = ktime_get_ns();
val = REG_RD(bp, MCP_REG_MCPR_IMC_COMMAND);
while (((val >> MCPR_IMC_COMMAND_IMC_STATUS_BITSHIFT) & 0x3) != 1) {
- udelay(10);
- val = REG_RD(bp, MCP_REG_MCPR_IMC_COMMAND);
- if (i++ > 1000) {
- DP(NETIF_MSG_LINK, "rd op timed out after %d try\n", i);
+ delta = ktime_get_ns() - t0;
+ if (delta > 10 * NSEC_PER_MSEC) {
+ DP(NETIF_MSG_LINK, "rd op timed out after %Lu ns\n",
+ delta);
rc = -EFAULT;
break;
}
+ usleep_range(10, 20);
+ val = REG_RD(bp, MCP_REG_MCPR_IMC_COMMAND);
}
if (rc == -EFAULT)
return rc;