net: phy: add paged phy register accessors
Add a set of paged phy register accessors which are inherently safe in
their design against other accesses interfering with the paged access.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/phy/phy-core.c b/drivers/net/phy/phy-core.c
index 028c098..48e762b 100644
--- a/drivers/net/phy/phy-core.c
+++ b/drivers/net/phy/phy-core.c
@@ -348,3 +348,160 @@ int __phy_modify(struct phy_device *phydev, u32 regnum, u16 mask, u16 set)
return ret;
}
EXPORT_SYMBOL_GPL(__phy_modify);
+
+static int __phy_read_page(struct phy_device *phydev)
+{
+ return phydev->drv->read_page(phydev);
+}
+
+static int __phy_write_page(struct phy_device *phydev, int page)
+{
+ return phydev->drv->write_page(phydev, page);
+}
+
+/**
+ * phy_save_page() - take the bus lock and save the current page
+ * @phydev: a pointer to a &struct phy_device
+ *
+ * Take the MDIO bus lock, and return the current page number. On error,
+ * returns a negative errno. phy_restore_page() must always be called
+ * after this, irrespective of success or failure of this call.
+ */
+int phy_save_page(struct phy_device *phydev)
+{
+ mutex_lock(&phydev->mdio.bus->mdio_lock);
+ return __phy_read_page(phydev);
+}
+EXPORT_SYMBOL_GPL(phy_save_page);
+
+/**
+ * phy_select_page() - take the bus lock, save the current page, and set a page
+ * @phydev: a pointer to a &struct phy_device
+ * @page: desired page
+ *
+ * Take the MDIO bus lock to protect against concurrent access, save the
+ * current PHY page, and set the current page. On error, returns a
+ * negative errno, otherwise returns the previous page number.
+ * phy_restore_page() must always be called after this, irrespective
+ * of success or failure of this call.
+ */
+int phy_select_page(struct phy_device *phydev, int page)
+{
+ int ret, oldpage;
+
+ oldpage = ret = phy_save_page(phydev);
+ if (ret < 0)
+ return ret;
+
+ if (oldpage != page) {
+ ret = __phy_write_page(phydev, page);
+ if (ret < 0)
+ return ret;
+ }
+
+ return oldpage;
+}
+EXPORT_SYMBOL_GPL(phy_select_page);
+
+/**
+ * phy_restore_page() - restore the page register and release the bus lock
+ * @phydev: a pointer to a &struct phy_device
+ * @oldpage: the old page, return value from phy_save_page() or phy_select_page()
+ * @ret: operation's return code
+ *
+ * Release the MDIO bus lock, restoring @oldpage if it is a valid page.
+ * This function propagates the earliest error code from the group of
+ * operations.
+ *
+ * Returns:
+ * @oldpage if it was a negative value, otherwise
+ * @ret if it was a negative errno value, otherwise
+ * phy_write_page()'s negative value if it were in error, otherwise
+ * @ret.
+ */
+int phy_restore_page(struct phy_device *phydev, int oldpage, int ret)
+{
+ int r;
+
+ if (oldpage >= 0) {
+ r = __phy_write_page(phydev, oldpage);
+
+ /* Propagate the operation return code if the page write
+ * was successful.
+ */
+ if (ret >= 0 && r < 0)
+ ret = r;
+ } else {
+ /* Propagate the phy page selection error code */
+ ret = oldpage;
+ }
+
+ mutex_unlock(&phydev->mdio.bus->mdio_lock);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(phy_restore_page);
+
+/**
+ * phy_read_paged() - Convenience function for reading a paged register
+ * @phydev: a pointer to a &struct phy_device
+ * @page: the page for the phy
+ * @regnum: register number
+ *
+ * Same rules as for phy_read().
+ */
+int phy_read_paged(struct phy_device *phydev, int page, u32 regnum)
+{
+ int ret = 0, oldpage;
+
+ oldpage = phy_select_page(phydev, page);
+ if (oldpage >= 0)
+ ret = __phy_read(phydev, regnum);
+
+ return phy_restore_page(phydev, oldpage, ret);
+}
+EXPORT_SYMBOL(phy_read_paged);
+
+/**
+ * phy_write_paged() - Convenience function for writing a paged register
+ * @phydev: a pointer to a &struct phy_device
+ * @page: the page for the phy
+ * @regnum: register number
+ * @val: value to write
+ *
+ * Same rules as for phy_write().
+ */
+int phy_write_paged(struct phy_device *phydev, int page, u32 regnum, u16 val)
+{
+ int ret = 0, oldpage;
+
+ oldpage = phy_select_page(phydev, page);
+ if (oldpage >= 0)
+ ret = __phy_write(phydev, regnum, val);
+
+ return phy_restore_page(phydev, oldpage, ret);
+}
+EXPORT_SYMBOL(phy_write_paged);
+
+/**
+ * phy_modify_paged() - Convenience function for modifying a paged register
+ * @phydev: a pointer to a &struct phy_device
+ * @page: the page for the phy
+ * @regnum: register number
+ * @mask: bit mask of bits to clear
+ * @set: bit mask of bits to set
+ *
+ * Same rules as for phy_read() and phy_write().
+ */
+int phy_modify_paged(struct phy_device *phydev, int page, u32 regnum,
+ u16 mask, u16 set)
+{
+ int ret = 0, oldpage;
+
+ oldpage = phy_select_page(phydev, page);
+ if (oldpage >= 0)
+ ret = __phy_modify(phydev, regnum, mask, set);
+
+ return phy_restore_page(phydev, oldpage, ret);
+}
+EXPORT_SYMBOL(phy_modify_paged);