Message-ID: <trinity-916ed524-e8a5-4534-b059-3ed707ec3881-1724520847823@3c-app-gmx-bs42>
Date: Sat, 24 Aug 2024 19:34:07 +0200
From: Hans-Frieder Vogt <hfdevel@....net>
To: Andrew Lunn <andrew@...n.ch>, Heiner Kallweit <hkallweit1@...il.com>,
 Russell King <linux@...linux.org.uk>, netdev@...r.kernel.org
Cc: Vladimir Oltean <vladimir.oltean@....com>, Bartosz Golaszewski
 <brgl@...ev.pl>
Subject: [PATCH net-next 1/2] net: phy: aquantia: create firmware name for
 aqr PHYs at runtime

Aquantia PHYs without EEPROM have to load the firmware via the file system and
upload it to the PHY via MDIO.
Because the Aquantia PHY firmware is different for the same PHY depending on the
MAC it is connected to, it is not possible to statically define the firmware name.
When in an embedded environment, the device-tree can provide the file name. But when the PHY is on a PCIe card, the file name needs to be provided in a different
way.

This patch creates a firmware file name at run time, based on the Aquantia PHY
name and the MDIO name. By this, firmware files for ths same PHY, but combined
with different MACs are distinguishable.

The proposed naming uses the scheme:
	mdio/phy-mdio_suffix
Or, in the case of the Tehuti TN9510 card (TN4010 MAC and AQR105 PHY), the firmware
file name will be
	tn40xx/aqr105-tn40xx_fw.cld

This naming style has been chosen in order to make the filename unique, but also
to place the firmware in a directory named after the MAC, where different firmwares
could be collected.

Signed-off-by: Hans-Frieder Vogt <hfdevel@....net>
---
 drivers/net/phy/aquantia/aquantia_firmware.c | 78 ++++++++++++++++++++
 1 file changed, 78 insertions(+)

diff --git a/drivers/net/phy/aquantia/aquantia_firmware.c b/drivers/net/phy/aquantia/aquantia_firmware.c
index 524627a36c6f..265bd6ee21da 100644
--- a/drivers/net/phy/aquantia/aquantia_firmware.c
+++ b/drivers/net/phy/aquantia/aquantia_firmware.c
@@ -5,6 +5,7 @@
 #include <linux/firmware.h>
 #include <linux/crc-itu-t.h>
 #include <linux/nvmem-consumer.h>
+#include <linux/ctype.h>	/* for tolower() */

 #include <asm/unaligned.h>

@@ -321,6 +322,81 @@ static int aqr_firmware_load_nvmem(struct phy_device *phydev)
 	return ret;
 }

+/* derive the filename of the firmware file from the PHY and the MDIO names
+ * Parts of filename:
+ *   mdio/phy-mdio_suffix
+ *    1    2   3    4
+ * allow name components 1 (= 3) and 2 to have same maximum length
+ */
+static int aqr_firmware_name(struct phy_device *phydev, const char **name)
+{
+#define AQUANTIA_FW_SUFFIX "_fw.cld"
+#define AQUANTIA_NAME "Aquantia "
+/* including the trailing zero */
+#define FIRMWARE_NAME_SIZE 64
+/* length of the name components 1, 2, 3 without the trailing zero */
+#define NAME_PART_SIZE ((FIRMWARE_NAME_SIZE - sizeof(AQUANTIA_FW_SUFFIX) - 2) / 3)
+	ssize_t len, mac_len;
+	char *fw_name;
+	int i, j;
+
+	/* sanity check: the phydev drv name needs to start with AQUANTIA_NAME */
+	if (strncmp(AQUANTIA_NAME, phydev->drv->name, strlen(AQUANTIA_NAME)))
+		return -EINVAL;
+
+	/* sanity check: the phydev drv name may not be longer than NAME_PART_SIZE */
+	if (strlen(phydev->drv->name) - strlen(AQUANTIA_NAME) > NAME_PART_SIZE)
+		return -E2BIG;
+
+	/* sanity check: the MDIO name must not be empty */
+	if (!phydev->mdio.bus->id[0])
+		return -EINVAL;
+
+	fw_name = devm_kzalloc(&phydev->mdio.dev, FIRMWARE_NAME_SIZE, GFP_KERNEL);
+	if (!fw_name)
+		return -ENOMEM;
+
+	/* first the directory name = MDIO bus name
+	 * (only name component, firmware name part 1; remove busids and the likes)
+	 * ignore the return value of strscpy: if the MAC/MDIO name is too long,
+	 * it will just be truncated
+	 */
+	strscpy(fw_name, phydev->mdio.bus->id, NAME_PART_SIZE + 1);
+	for (i = 0; fw_name[i]; i++) {
+		if (fw_name[i] == '-' || fw_name[i] == '_' || fw_name[i] == ':')
+			break;
+	}
+	mac_len = i;	/* without trailing zero */
+
+	fw_name[i++] = '/';
+
+	/* copy name part beyond AQUANTIA_NAME into our name buffer - name part 2 */
+	len = strscpy(&fw_name[i], phydev->drv->name + strlen(AQUANTIA_NAME),
+		      FIRMWARE_NAME_SIZE - i);
+	if (len < 0)
+		return len;	/* should never happen */
+
+	/* convert the name to lower case */
+	for (j = i; j < i + len; j++)
+		fw_name[j] = tolower(fw_name[j]);
+	i += len;
+
+	/* split the phy and mdio components with a dash */
+	fw_name[i++] = '-';
+
+	/* copy again the mac_name into fw_name - name part 3 */
+	memcpy(&fw_name[i], fw_name, mac_len);
+
+	/* copy file suffix (name part 4 - don't forget the trailing '\0') */
+	len = strscpy(&fw_name[i + mac_len], AQUANTIA_FW_SUFFIX, FIRMWARE_NAME_SIZE - i - mac_len);
+	if (len < 0)
+		return len;	/* should never happen */
+
+	if (name)
+		*name = fw_name;
+	return 0;
+}
+
 static int aqr_firmware_load_fs(struct phy_device *phydev)
 {
 	struct device *dev = &phydev->mdio.dev;
@@ -330,6 +406,8 @@ static int aqr_firmware_load_fs(struct phy_device *phydev)

 	ret = of_property_read_string(dev->of_node, "firmware-name",
 				      &fw_name);
+	if (ret)
+		ret = aqr_firmware_name(phydev, &fw_name);
 	if (ret)
 		return ret;

--
2.43.0

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