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Message-Id: <20230317113427.302162-3-noltari@gmail.com>
Date: Fri, 17 Mar 2023 12:34:26 +0100
From: Álvaro Fernández Rojas
<noltari@...il.com>
To: davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org,
pabeni@...hat.com, robh+dt@...nel.org,
krzysztof.kozlowski+dt@...aro.org, f.fainelli@...il.com,
jonas.gorski@...il.com, andrew@...n.ch, olteanv@...il.com,
hkallweit1@...il.com, linux@...linux.org.uk,
netdev@...r.kernel.org, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org
Cc: Álvaro Fernández Rojas
<noltari@...il.com>
Subject: [PATCH 2/3] net: dsa: b53: mmap: register MDIO Mux bus controller
b53 MMAP devices have a MDIO Mux bus controller that must be registered after
properly initializing the switch. If the MDIO Mux controller is registered
from a separate driver and the device has an external switch present, it will
cause a race condition which will hang the device.
Signed-off-by: Álvaro Fernández Rojas <noltari@...il.com>
---
drivers/net/dsa/b53/Kconfig | 1 +
drivers/net/dsa/b53/b53_mmap.c | 127 ++++++++++++++++++++++++++++++++-
2 files changed, 127 insertions(+), 1 deletion(-)
diff --git a/drivers/net/dsa/b53/Kconfig b/drivers/net/dsa/b53/Kconfig
index ebaa4a80d544..04450ee1ba82 100644
--- a/drivers/net/dsa/b53/Kconfig
+++ b/drivers/net/dsa/b53/Kconfig
@@ -26,6 +26,7 @@ config B53_MDIO_DRIVER
config B53_MMAP_DRIVER
tristate "B53 MMAP connected switch driver"
depends on B53 && HAS_IOMEM
+ select MDIO_BUS_MUX
default BCM63XX || BMIPS_GENERIC
help
Select to enable support for memory-mapped switches like the BCM63XX
diff --git a/drivers/net/dsa/b53/b53_mmap.c b/drivers/net/dsa/b53/b53_mmap.c
index e968322dfbf0..44becbb12bb5 100644
--- a/drivers/net/dsa/b53/b53_mmap.c
+++ b/drivers/net/dsa/b53/b53_mmap.c
@@ -18,15 +18,31 @@
#include <linux/bits.h>
#include <linux/kernel.h>
+#include <linux/mdio-mux.h>
#include <linux/module.h>
#include <linux/io.h>
+#include <linux/of_mdio.h>
#include <linux/platform_device.h>
#include <linux/platform_data/b53.h>
#include "b53_priv.h"
+#define REG_MDIOC 0xb0
+#define REG_MDIOC_EXT_MASK BIT(16)
+#define REG_MDIOC_REG_SHIFT 20
+#define REG_MDIOC_PHYID_SHIFT 25
+#define REG_MDIOC_RD_MASK BIT(30)
+#define REG_MDIOC_WR_MASK BIT(31)
+
+#define REG_MDIOD 0xb4
+
struct b53_mmap_priv {
void __iomem *regs;
+
+ /* Internal MDIO Mux bus */
+ struct mii_bus *mbus;
+ int ext_phy;
+ void *mux_handle;
};
static int b53_mmap_read8(struct b53_device *dev, u8 page, u8 reg, u8 *val)
@@ -229,6 +245,111 @@ static const struct b53_io_ops b53_mmap_ops = {
.write64 = b53_mmap_write64,
};
+static int b53_mmap_mdiomux_read(struct mii_bus *bus, int phy_id, int loc)
+{
+ struct b53_device *dev = bus->priv;
+ struct b53_mmap_priv *priv = dev->priv;
+ uint32_t reg;
+ uint16_t val;
+
+ b53_mmap_write32(dev, 0, REG_MDIOC, 0);
+
+ reg = REG_MDIOC_RD_MASK |
+ (phy_id << REG_MDIOC_PHYID_SHIFT) |
+ (loc << REG_MDIOC_REG_SHIFT);
+ if (priv->ext_phy)
+ reg |= REG_MDIOC_EXT_MASK;
+
+ b53_mmap_write32(dev, 0, REG_MDIOC, reg);
+ udelay(50);
+ b53_mmap_read16(dev, 0, REG_MDIOD, &val);
+
+ return (int) val;
+}
+
+static int b53_mmap_mdiomux_write(struct mii_bus *bus, int phy_id, int loc,
+ uint16_t val)
+{
+ struct b53_device *dev = bus->priv;
+ struct b53_mmap_priv *priv = dev->priv;
+ uint32_t reg;
+
+ b53_mmap_write32(dev, 0, REG_MDIOC, 0);
+
+ reg = REG_MDIOC_WR_MASK |
+ (phy_id << REG_MDIOC_PHYID_SHIFT) |
+ (loc << REG_MDIOC_REG_SHIFT);
+ if (priv->ext_phy)
+ reg |= REG_MDIOC_EXT_MASK;
+ reg |= val;
+
+ b53_mmap_write32(dev, 0, REG_MDIOC, reg);
+ udelay(50);
+
+ return 0;
+}
+
+static int b53_mmap_mdiomux_switch_fn(int current_child, int desired_child,
+ void *data)
+{
+ struct b53_device *dev = data;
+ struct b53_mmap_priv *priv = dev->priv;
+
+ priv->ext_phy = desired_child;
+
+ return 0;
+}
+
+static int b53_mmap_mdiomux_init(struct b53_device *priv)
+{
+ struct b53_mmap_priv *mpriv = priv->priv;
+ struct device *dev = priv->dev;
+ struct device_node *np = dev->of_node;
+ struct device_node *mnp;
+ struct mii_bus *mbus;
+ int ret;
+
+ mnp = of_get_child_by_name(np, "mdio-mux");
+ if (!mnp)
+ return 0;
+
+ mbus = devm_mdiobus_alloc(dev);
+ if (!mbus) {
+ of_node_put(mnp);
+ return -ENOMEM;
+ }
+
+ mbus->priv = priv;
+ mbus->name = np->full_name;
+ snprintf(mbus->id, MII_BUS_ID_SIZE, "%pOF", np);
+ mbus->parent = dev;
+ mbus->read = b53_mmap_mdiomux_read;
+ mbus->write = b53_mmap_mdiomux_write;
+ mbus->phy_mask = 0x3f;
+
+ ret = devm_of_mdiobus_register(dev, mbus, mnp);
+ if (ret) {
+ of_node_put(mnp);
+ dev_err(dev, "MDIO mux registration failed\n");
+ return ret;
+ }
+
+ ret = mdio_mux_init(dev, mnp, b53_mmap_mdiomux_switch_fn,
+ &mpriv->mux_handle, priv, mbus);
+ of_node_put(mnp);
+ if (ret) {
+ mdiobus_unregister(mbus);
+ dev_err(dev, "MDIO mux initialization failed\n");
+ return ret;
+ }
+
+ dev_info(dev, "MDIO mux bus init\n");
+
+ mpriv->mbus = mbus;
+
+ return 0;
+}
+
static int b53_mmap_probe_of(struct platform_device *pdev,
struct b53_platform_data **ppdata)
{
@@ -306,7 +427,11 @@ static int b53_mmap_probe(struct platform_device *pdev)
platform_set_drvdata(pdev, dev);
- return b53_switch_register(dev);
+ ret = b53_switch_register(dev);
+ if (ret)
+ return ret;
+
+ return b53_mmap_mdiomux_init(dev);
}
static int b53_mmap_remove(struct platform_device *pdev)
--
2.30.2
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