[PATCH 0/3] net: qcom/emac: various minor improvements

[PATCH 0/3] net: qcom/emac: various minor improvements

[Timur Tabi]

A collection of minor fixes and features to the Qualcomm Technologies
EMAC network driver.

Timur Tabi (3):
  net: qcom/emac: add shutdown function
  net: qcom/emac: do not reset the EMAC during initialization
  net: qcom/emac: add support for emulation systems

 drivers/net/ethernet/qualcomm/emac/emac-sgmii.c | 23 +++++++++++++++++++++--
 drivers/net/ethernet/qualcomm/emac/emac.c       | 16 ++++++++++++++--
 2 files changed, 35 insertions(+), 4 deletions(-)

-- 
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm
Technologies, Inc.  Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.

[PATCH 1/3] net: qcom/emac: add shutdown function

[Timur Tabi]

The shutdown function halts all DMA and interrupts, so that all
operations are discontinued when the system shuts down, e.g. via
kexec or a forced reboot.

Tested-by: Tyler Baicar <tbaicar@codeaurora.org>
Signed-off-by: Timur Tabi <timur@codeaurora.org>
---
 drivers/net/ethernet/qualcomm/emac/emac.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/net/ethernet/qualcomm/emac/emac.c b/drivers/net/ethernet/qualcomm/emac/emac.c
index 98a326f..77c5c92 100644
--- a/drivers/net/ethernet/qualcomm/emac/emac.c
+++ b/drivers/net/ethernet/qualcomm/emac/emac.c
@@ -762,6 +762,19 @@ static int emac_remove(struct platform_device *pdev)
 	return 0;
 }
 
+static void emac_shutdown(struct platform_device *pdev)
+{
+	struct net_device *netdev = dev_get_drvdata(&pdev->dev);
+	struct emac_adapter *adpt = netdev_priv(netdev);
+	struct emac_sgmii *sgmii = &adpt->phy;
+
+	/* Closing the SGMII turns off its interrupts */
+	sgmii->close(adpt);
+
+	/* Resetting the MAC turns off all DMA and its interrupts */
+	emac_mac_reset(adpt);
+}
+
 static struct platform_driver emac_platform_driver = {
 	.probe	= emac_probe,
 	.remove	= emac_remove,
@@ -770,6 +783,7 @@ static int emac_remove(struct platform_device *pdev)
 		.of_match_table = emac_dt_match,
 		.acpi_match_table = ACPI_PTR(emac_acpi_match),
 	},
+	.shutdown = emac_shutdown,
 };
 
 module_platform_driver(emac_platform_driver);
-- 
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm
Technologies, Inc.  Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.

[PATCH 2/3] net: qcom/emac: do not reset the EMAC during initialization

[Timur Tabi]

It doesn't make sense to reset the EMAC in the middle of initializing
it during the probe.

Tested-by: Richard Ruigrok <rruigrok@codeaurora.org>
Signed-off-by: Timur Tabi <timur@codeaurora.org>
---
 drivers/net/ethernet/qualcomm/emac/emac.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/net/ethernet/qualcomm/emac/emac.c b/drivers/net/ethernet/qualcomm/emac/emac.c
index 77c5c92..746d94e 100644
--- a/drivers/net/ethernet/qualcomm/emac/emac.c
+++ b/drivers/net/ethernet/qualcomm/emac/emac.c
@@ -683,8 +683,6 @@ static int emac_probe(struct platform_device *pdev)
 		goto err_undo_mdiobus;
 	}
 
-	emac_mac_reset(adpt);
-
 	/* set hw features */
 	netdev->features = NETIF_F_SG | NETIF_F_HW_CSUM | NETIF_F_RXCSUM |
 			NETIF_F_TSO | NETIF_F_TSO6 | NETIF_F_HW_VLAN_CTAG_RX |
-- 
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm
Technologies, Inc.  Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.

[PATCH 3/3] net: qcom/emac: add support for emulation systems

[Timur Tabi]

On emulation systems, the EMAC's internal PHY ("SGMII") is not present,
but is not needed for network functionality.  So just display a warning
message and ignore the SGMII.

Tested-by: Philip Elcan <pelcan@codeaurora.org>
Tested-by: Adam Wallis <awallis@codeaurora.org>
Signed-off-by: Timur Tabi <timur@codeaurora.org>
---
 drivers/net/ethernet/qualcomm/emac/emac-sgmii.c | 23 +++++++++++++++++++++--
 1 file changed, 21 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/qualcomm/emac/emac-sgmii.c b/drivers/net/ethernet/qualcomm/emac/emac-sgmii.c
index 18c184e..29ba37a 100644
--- a/drivers/net/ethernet/qualcomm/emac/emac-sgmii.c
+++ b/drivers/net/ethernet/qualcomm/emac/emac-sgmii.c
@@ -297,6 +297,14 @@ static int emac_sgmii_acpi_match(struct device *dev, void *data)
 	{}
 };
 
+/* Dummy function for systems without an internal PHY. This avoids having
+ * to check for NULL pointers before calling the functions.
+ */
+static int emac_sgmii_dummy(struct emac_adapter *adpt)
+{
+	return 0;
+}
+
 int emac_sgmii_config(struct platform_device *pdev, struct emac_adapter *adpt)
 {
 	struct platform_device *sgmii_pdev = NULL;
@@ -311,8 +319,19 @@ int emac_sgmii_config(struct platform_device *pdev, struct emac_adapter *adpt)
 					emac_sgmii_acpi_match);
 
 		if (!dev) {
-			dev_err(&pdev->dev, "cannot find internal phy node\n");
-			return -ENODEV;
+			dev_warn(&pdev->dev, "cannot find internal phy node\n");
+			/* There is typically no internal PHY on emulation
+			 * systems, so if we can't find the node, assume
+			 * we are on an emulation system and stub-out
+			 * support for the internal PHY.  These systems only
+			 * use ACPI.
+			 */
+			phy->open = emac_sgmii_dummy;
+			phy->close = emac_sgmii_dummy;
+			phy->link_up = emac_sgmii_dummy;
+			phy->link_down = emac_sgmii_dummy;
+
+			return 0;
 		}
 
 		sgmii_pdev = to_platform_device(dev);
-- 
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm
Technologies, Inc.  Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.

Re: [PATCH 2/3] net: qcom/emac: do not reset the EMAC during initialization

[David Miller]

From: Timur Tabi <timur@codeaurora.org>
Date: Thu, 22 Jun 2017 13:05:31 -0500

> It doesn't make sense to reset the EMAC in the middle of initializing
> it during the probe.
> 
> Tested-by: Richard Ruigrok <rruigrok@codeaurora.org>
> Signed-off-by: Timur Tabi <timur@codeaurora.org>

Why not?

What if the boot loader or something else left the chip in
a weird state?

I'm not applying this.

If it's correct, the explanation in this commit message need
to be imporved.  The change must be better justified.

Re: [PATCH 2/3] net: qcom/emac: do not reset the EMAC during initialization

[Timur Tabi]

On 06/23/2017 01:00 PM, David Miller wrote:
> What if the boot loader or something else left the chip in
> a weird state?

We depend on the boot loader leaving the NIC in a very specific state 
already, otherwise the driver can't initialize the hardware.  The 
firmware has to pre-initialize the EMAC for us.

Not only that, but the driver was resetting the MAC *after* programming 
the clocks (on non-ACPI systems) and initializing both PHYs.

> I'm not applying this.
> 
> If it's correct, the explanation in this commit message need
> to be imporved.  The change must be better justified.

Since this is for ACPI systems, I could do this:

	if (!has_acpi_companion(&pdev->dev))
		emac_mac_reset(adpt);

But at the very least, the call should be moved to earlier in the function.

-- 
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm
Technologies, Inc.  Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.

Re: [PATCH 2/3] net: qcom/emac: do not reset the EMAC during initialization

[David Miller]

From: Timur Tabi <timur@codeaurora.org>
Date: Fri, 23 Jun 2017 13:37:58 -0500

> On 06/23/2017 01:00 PM, David Miller wrote:
>> What if the boot loader or something else left the chip in
>> a weird state?
> 
> We depend on the boot loader leaving the NIC in a very specific state
> already, otherwise the driver can't initialize the hardware.  The
> firmware has to pre-initialize the EMAC for us.
> 
> Not only that, but the driver was resetting the MAC *after*
> programming the clocks (on non-ACPI systems) and initializing both
> PHYs.
> 
>> I'm not applying this.
>> If it's correct, the explanation in this commit message need
>> to be imporved.  The change must be better justified.
> 
> Since this is for ACPI systems, I could do this:
> 
> 	if (!has_acpi_companion(&pdev->dev))
> 		emac_mac_reset(adpt);
> 
> But at the very least, the call should be moved to earlier in the
> function.

Please just explain the ACPI situation in the commit log message
and resubmit the series.

Thanks.

[PATCH 3/3] net: qcom/emac: add support for emulation systems

[Timur Tabi]

On emulation systems, the EMAC's internal PHY ("SGMII") is not present,
but is not needed for network functionality.  So just display a warning
message and ignore the SGMII.

Tested-by: Philip Elcan <pelcan@codeaurora.org>
Tested-by: Adam Wallis <awallis@codeaurora.org>
Signed-off-by: Timur Tabi <timur@codeaurora.org>
---
 drivers/net/ethernet/qualcomm/emac/emac-sgmii.c | 23 +++++++++++++++++++++--
 1 file changed, 21 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/qualcomm/emac/emac-sgmii.c b/drivers/net/ethernet/qualcomm/emac/emac-sgmii.c
index 18c184e..29ba37a 100644
--- a/drivers/net/ethernet/qualcomm/emac/emac-sgmii.c
+++ b/drivers/net/ethernet/qualcomm/emac/emac-sgmii.c
@@ -297,6 +297,14 @@ static int emac_sgmii_acpi_match(struct device *dev, void *data)
 	{}
 };
 
+/* Dummy function for systems without an internal PHY. This avoids having
+ * to check for NULL pointers before calling the functions.
+ */
+static int emac_sgmii_dummy(struct emac_adapter *adpt)
+{
+	return 0;
+}
+
 int emac_sgmii_config(struct platform_device *pdev, struct emac_adapter *adpt)
 {
 	struct platform_device *sgmii_pdev = NULL;
@@ -311,8 +319,19 @@ int emac_sgmii_config(struct platform_device *pdev, struct emac_adapter *adpt)
 					emac_sgmii_acpi_match);
 
 		if (!dev) {
-			dev_err(&pdev->dev, "cannot find internal phy node\n");
-			return -ENODEV;
+			dev_warn(&pdev->dev, "cannot find internal phy node\n");
+			/* There is typically no internal PHY on emulation
+			 * systems, so if we can't find the node, assume
+			 * we are on an emulation system and stub-out
+			 * support for the internal PHY.  These systems only
+			 * use ACPI.
+			 */
+			phy->open = emac_sgmii_dummy;
+			phy->close = emac_sgmii_dummy;
+			phy->link_up = emac_sgmii_dummy;
+			phy->link_down = emac_sgmii_dummy;
+
+			return 0;
 		}
 
 		sgmii_pdev = to_platform_device(dev);
-- 
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm
Technologies, Inc.  Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.