diff mbox series

[net,v3] net: fec: Refactor MAC reset to function

Message ID 20250204093756.253642-2-csokas.bence@prolan.hu (mailing list archive)
State New
Delegated to: Netdev Maintainers
Headers show
Series [net,v3] net: fec: Refactor MAC reset to function | expand

Checks

Context Check Description
netdev/series_format success Single patches do not need cover letters
netdev/tree_selection success Clearly marked for net
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 11 of 11 maintainers
netdev/build_clang success Errors and warnings before: 2 this patch: 2
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch warning CHECK: usleep_range is preferred over udelay; see function description of usleep_range() and udelay().
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2025-02-04--15-00 (tests: 886)

Commit Message

Csókás Bence Feb. 4, 2025, 9:37 a.m. UTC
The core is reset both in `fec_restart()` (called on link-up) and
`fec_stop()` (going to sleep, driver remove etc.). These two functions
had their separate implementations, which was at first only a register
write and a `udelay()` (and the accompanying block comment). However,
since then we got soft-reset (MAC disable) and Wake-on-LAN support, which
meant that these implementations diverged, often causing bugs.

For instance, as of now, `fec_stop()` does not check for
`FEC_QUIRK_NO_HARD_RESET`, meaning the MII/RMII mode is cleared on eg.
a PM power-down event; and `fec_restart()` missed the refactor renaming
the "magic" constant `1` to `FEC_ECR_RESET`.

To harmonize current implementations, and eliminate this source of
potential future bugs, refactor implementation to a common function.

Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Fixes: c730ab423bfa ("net: fec: Fix temporary RMII clock reset on link up")
Fixes: ff049886671c ("net: fec: Refactor: #define magic constants")
Signed-off-by: Csókás, Bence <csokas.bence@prolan.hu>
---

Notes:
    Recommended options for this patch:
    `--color-moved --color-moved-ws=allow-indentation-change`
    Changes in v2:
    * collect Michal's tag
    * reformat message to 75 cols
    * fix missing `u32 val`
    Changes in v3:
    * rename parameter to `allow_wol`
    Changes in v3:
    * clarify message
    * collect Jacob's tag
    * rebased onto c2933b2befe2

 drivers/net/ethernet/freescale/fec_main.c | 52 +++++++++++------------
 1 file changed, 25 insertions(+), 27 deletions(-)

Comments

Jakub Kicinski Feb. 4, 2025, 3:45 p.m. UTC | #1
On Tue, 4 Feb 2025 10:37:54 +0100 Csókás, Bence wrote:
> For instance, as of now, `fec_stop()` does not check for
> `FEC_QUIRK_NO_HARD_RESET`, meaning the MII/RMII mode is cleared on eg.
> a PM power-down event; and `fec_restart()` missed the refactor renaming
> the "magic" constant `1` to `FEC_ECR_RESET`.

Laurent responded to v1 saying this was intentional. Please give more
details on how problem you're seeing and on what platforms. Otherwise
this is not a fix but refactoring.

Please don't post new versions in-reply-to, and add lore links to
the previous version in the changelog.
Csókás Bence Feb. 5, 2025, 1:53 p.m. UTC | #2
Hi,

On 2025. 02. 04. 16:45, Jakub Kicinski wrote:
 > Please don't post new versions in-reply-to, and add lore links to
 > the previous version in the changelog.

Will do. Is it okay to only include the last version, or should I 
collect them going back to v1?

> On Tue, 4 Feb 2025 10:37:54 +0100 Csókás, Bence wrote:
>> For instance, as of now, `fec_stop()` does not check for
>> `FEC_QUIRK_NO_HARD_RESET`, meaning the MII/RMII mode is cleared on eg.
>> a PM power-down event; and `fec_restart()` missed the refactor renaming
>> the "magic" constant `1` to `FEC_ECR_RESET`.
> 
> Laurent responded to v1 saying this was intentional. Please give more
> details on how problem you're seeing and on what platforms. Otherwise
> this is not a fix but refactoring.

True, but he also said:
On 2025. 01. 21. 17:09, Badel, Laurent wrote:
 > If others disagree and there's a consensus that this change is ok, 
I'm happy
 > for the patch to get through, but I tend to err on the side of 
caution in such
 > cases.

I understand he is cautious, but I'd argue that the fact that two people 
already posted Reviewed-by: (not counting Simon, who since withdrew it), 
means that others also agree that we should err on the OTHER side of 
caution, and do the check in both cases. He also mentions that the 
reason he didn't do the check in `fec_stop()` was that he believed that 
the only time that gets called is on driver/interface remove, but that 
is not the case, as I outlined in the message already.

Bence
diff mbox series

Patch

diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
index f7c4ce8e9a26..a86cfebedaa8 100644
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -1093,6 +1093,29 @@  static void fec_enet_enable_ring(struct net_device *ndev)
 	}
 }
 
+/* Whack a reset.  We should wait for this.
+ * For i.MX6SX SOC, enet use AXI bus, we use disable MAC
+ * instead of reset MAC itself.
+ */
+static void fec_ctrl_reset(struct fec_enet_private *fep, bool allow_wol)
+{
+	u32 val;
+
+	if (!allow_wol || !(fep->wol_flag & FEC_WOL_FLAG_SLEEP_ON)) {
+		if (fep->quirks & FEC_QUIRK_HAS_MULTI_QUEUES ||
+		    ((fep->quirks & FEC_QUIRK_NO_HARD_RESET) && fep->link)) {
+			writel(0, fep->hwp + FEC_ECNTRL);
+		} else {
+			writel(FEC_ECR_RESET, fep->hwp + FEC_ECNTRL);
+			udelay(10);
+		}
+	} else {
+		val = readl(fep->hwp + FEC_ECNTRL);
+		val |= (FEC_ECR_MAGICEN | FEC_ECR_SLEEP);
+		writel(val, fep->hwp + FEC_ECNTRL);
+	}
+}
+
 /*
  * This function is called to start or restart the FEC during a link
  * change, transmit timeout, or to reconfigure the FEC.  The network
@@ -1109,17 +1132,7 @@  fec_restart(struct net_device *ndev)
 	if (fep->bufdesc_ex)
 		fec_ptp_save_state(fep);
 
-	/* Whack a reset.  We should wait for this.
-	 * For i.MX6SX SOC, enet use AXI bus, we use disable MAC
-	 * instead of reset MAC itself.
-	 */
-	if (fep->quirks & FEC_QUIRK_HAS_MULTI_QUEUES ||
-	    ((fep->quirks & FEC_QUIRK_NO_HARD_RESET) && fep->link)) {
-		writel(0, fep->hwp + FEC_ECNTRL);
-	} else {
-		writel(1, fep->hwp + FEC_ECNTRL);
-		udelay(10);
-	}
+	fec_ctrl_reset(fep, false);
 
 	/*
 	 * enet-mac reset will reset mac address registers too,
@@ -1373,22 +1386,7 @@  fec_stop(struct net_device *ndev)
 	if (fep->bufdesc_ex)
 		fec_ptp_save_state(fep);
 
-	/* Whack a reset.  We should wait for this.
-	 * For i.MX6SX SOC, enet use AXI bus, we use disable MAC
-	 * instead of reset MAC itself.
-	 */
-	if (!(fep->wol_flag & FEC_WOL_FLAG_SLEEP_ON)) {
-		if (fep->quirks & FEC_QUIRK_HAS_MULTI_QUEUES) {
-			writel(0, fep->hwp + FEC_ECNTRL);
-		} else {
-			writel(FEC_ECR_RESET, fep->hwp + FEC_ECNTRL);
-			udelay(10);
-		}
-	} else {
-		val = readl(fep->hwp + FEC_ECNTRL);
-		val |= (FEC_ECR_MAGICEN | FEC_ECR_SLEEP);
-		writel(val, fep->hwp + FEC_ECNTRL);
-	}
+	fec_ctrl_reset(fep, true);
 	writel(fep->phy_speed, fep->hwp + FEC_MII_SPEED);
 	writel(FEC_DEFAULT_IMASK, fep->hwp + FEC_IMASK);