ibm_newemac: PowerPC 440EP/440GR EMAC PHY clock workaround

This patch adds ibm_newemac PHY clock workaround for 440EP/440GR EMAC
attached to a PHY which doesn't generate RX clock if there is no link.
The code is based on the previous ibm_emac driver stuff. The 440EP/440GR
allows controlling each EMAC clock separately as opposed to global clock
selection for 440GX.

BenH: Made that #ifdef CONFIG_PPC_DCR_NATIVE for now as dcri_* stuff doesn't
exist for MMIO type DCRs like Cell. Some future rework & improvements of the
DCR infrastructure will make that cleaner but for now, this makes it work.

Signed-off-by: Valentine Barshak <vbarshak@ru.mvista.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

2 files changed, 47 insertions, 2 deletions

diff --git a/drivers/net/ibm_newemac/core.c b/drivers/net/ibm_newemac/core.c
index 4176dd6a2e83..490d690b5e7f 100644
--- a/drivers/net/ibm_newemac/core.c
+++ b/drivers/net/ibm_newemac/core.c
@@ -129,10 +129,35 @@ static struct device_node *emac_boot_list[EMAC_BOOT_LIST_SIZE];
 static inline void emac_report_timeout_error(struct emac_instance *dev,
                                              const char *error)
 {
-        if (net_ratelimit())
+        if (emac_has_feature(dev, EMAC_FTR_440GX_PHY_CLK_FIX |
+                                  EMAC_FTR_440EP_PHY_CLK_FIX))
+                DBG(dev, "%s" NL, error);
+        else if (net_ratelimit())
                 printk(KERN_ERR "%s: %s\n", dev->ndev->name, error);
 }
 
+/* EMAC PHY clock workaround:
+ * 440EP/440GR has more sane SDR0_MFR register implementation than 440GX,
+ * which allows controlling each EMAC clock
+ */
+static inline void emac_rx_clk_tx(struct emac_instance *dev)
+{
+#ifdef CONFIG_PPC_DCR_NATIVE
+        if (emac_has_feature(dev, EMAC_FTR_440EP_PHY_CLK_FIX))
+                dcri_clrset(SDR0, SDR0_MFR,
+                            0, SDR0_MFR_ECS >> dev->cell_index);
+#endif
+}
+
+static inline void emac_rx_clk_default(struct emac_instance *dev)
+{
+#ifdef CONFIG_PPC_DCR_NATIVE
+        if (emac_has_feature(dev, EMAC_FTR_440EP_PHY_CLK_FIX))
+                dcri_clrset(SDR0, SDR0_MFR,
+                            SDR0_MFR_ECS >> dev->cell_index, 0);
+#endif
+}
+
 /* PHY polling intervals */
 #define PHY_POLL_LINK_ON        HZ
 #define PHY_POLL_LINK_OFF       (HZ / 5)
@@ -1099,9 +1124,11 @@ static int emac_open(struct net_device *ndev)
                 int link_poll_interval;
                 if (dev->phy.def->ops->poll_link(&dev->phy)) {
                         dev->phy.def->ops->read_link(&dev->phy);
+                        emac_rx_clk_default(dev);
                         netif_carrier_on(dev->ndev);
                         link_poll_interval = PHY_POLL_LINK_ON;
                 } else {
+                        emac_rx_clk_tx(dev);
                         netif_carrier_off(dev->ndev);
                         link_poll_interval = PHY_POLL_LINK_OFF;
                 }
@@ -1179,6 +1206,7 @@ static void emac_link_timer(struct work_struct *work)
 
         if (dev->phy.def->ops->poll_link(&dev->phy)) {
                 if (!netif_carrier_ok(dev->ndev)) {
+                        emac_rx_clk_default(dev);
                         /* Get new link parameters */
                         dev->phy.def->ops->read_link(&dev->phy);
 
@@ -1191,6 +1219,7 @@ static void emac_link_timer(struct work_struct *work)
                 link_poll_interval = PHY_POLL_LINK_ON;
         } else {
                 if (netif_carrier_ok(dev->ndev)) {
+                        emac_rx_clk_tx(dev);
                         netif_carrier_off(dev->ndev);
                         netif_tx_disable(dev->ndev);
                         emac_reinitialize(dev);
@@ -2340,6 +2369,14 @@ static int __devinit emac_init_phy(struct emac_instance *dev)
         if (emac_has_feature(dev, EMAC_FTR_440GX_PHY_CLK_FIX))
                 dcri_clrset(SDR0, SDR0_MFR, 0, SDR0_MFR_ECS);
 #endif
+        /* PHY clock workaround */
+        emac_rx_clk_tx(dev);
+
+        /* Enable internal clock source on 440GX*/
+#ifdef CONFIG_PPC_DCR_NATIVE
+        if (emac_has_feature(dev, EMAC_FTR_440GX_PHY_CLK_FIX))
+                dcri_clrset(SDR0, SDR0_MFR, 0, SDR0_MFR_ECS);
+#endif
         /* Configure EMAC with defaults so we can at least use MDIO
          * This is needed mostly for 440GX
          */
@@ -2507,6 +2544,10 @@ static int __devinit emac_init_config(struct emac_instance *dev)
                 dev->features |= EMAC_FTR_EMAC4;
                 if (of_device_is_compatible(np, "ibm,emac-440gx"))
                         dev->features |= EMAC_FTR_440GX_PHY_CLK_FIX;
+        } else {
+                if (of_device_is_compatible(np, "ibm,emac-440ep") ||
+                    of_device_is_compatible(np, "ibm,emac-440gr"))
+                        dev->features |= EMAC_FTR_440EP_PHY_CLK_FIX;
         }
 
         /* Fixup some feature bits based on the device tree */
diff --git a/drivers/net/ibm_newemac/core.h b/drivers/net/ibm_newemac/core.h
index 96ec48266b4a..1683db9870a4 100644
--- a/drivers/net/ibm_newemac/core.h
+++ b/drivers/net/ibm_newemac/core.h
@@ -305,6 +305,10 @@ struct emac_instance {
  * Set if we need phy clock workaround for 440gx
  */
 #define EMAC_FTR_440GX_PHY_CLK_FIX      0x00000080
+/*
+ * Set if we need phy clock workaround for 440ep or 440gr
+ */
+#define EMAC_FTR_440EP_PHY_CLK_FIX      0x00000100
 
 
 /* Right now, we don't quite handle the always/possible masks on the
@@ -328,7 +332,7 @@ enum {
 #ifdef CONFIG_IBM_NEW_EMAC_RGMII
             EMAC_FTR_HAS_RGMII  |
 #endif
-            0,
+        EMAC_FTR_440EP_PHY_CLK_FIX,
 };
 
 static inline int emac_has_feature(struct emac_instance *dev,