net: stmmac: fix get_hw_feature() on old hardware

BugLink: https://bugs.launchpad.net/bugs/1951291
commit 075da584bae2da6a37428d59a477b6bdad430ac3 upstream.

Some old IPs do not provide the hardware feature register.
On these IPs, this register is read 0x00000000.

In old driver version, this feature was handled but a regression came
with the commit f10a6a3541b4 ("stmmac: rework get_hw_feature function").
Indeed, this commit removes the return value in dma->get_hw_feature().
This return value was used to indicate the validity of retrieved
information and used later on in stmmac_hw_init() to override
priv->plat data if this hardware feature were valid.

This patch restores the return code in ->get_hw_feature() in order
to indicate the hardware feature validity and override priv->plat
data only if this hardware feature is valid.

Fixes: f10a6a3541b4 ("stmmac: rework get_hw_feature function")
Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c b/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c
index 2bac49b49f739233e5e9f94d2d8bc37d46162c76..fbf2deafe8ba31c33cfc08acbc1396c646bab6cc 100644 (file)
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c
@@ -218,11 +218,18 @@ static void dwmac1000_dump_dma_regs(void __iomem *ioaddr, u32 *reg_space)
                                readl(ioaddr + DMA_BUS_MODE + i * 4);
 }
 
-static void dwmac1000_get_hw_feature(void __iomem *ioaddr,
-                                    struct dma_features *dma_cap)
+static int dwmac1000_get_hw_feature(void __iomem *ioaddr,
+                                   struct dma_features *dma_cap)
 {
        u32 hw_cap = readl(ioaddr + DMA_HW_FEATURE);
 
+       if (!hw_cap) {
+               /* 0x00000000 is the value read on old hardware that does not
+                * implement this register
+                */
+               return -EOPNOTSUPP;
+       }
+
        dma_cap->mbps_10_100 = (hw_cap & DMA_HW_FEAT_MIISEL);
        dma_cap->mbps_1000 = (hw_cap & DMA_HW_FEAT_GMIISEL) >> 1;
        dma_cap->half_duplex = (hw_cap & DMA_HW_FEAT_HDSEL) >> 2;
@@ -252,6 +259,8 @@ static void dwmac1000_get_hw_feature(void __iomem *ioaddr,
        dma_cap->number_tx_channel = (hw_cap & DMA_HW_FEAT_TXCHCNT) >> 22;
        /* Alternate (enhanced) DESC mode */
        dma_cap->enh_desc = (hw_cap & DMA_HW_FEAT_ENHDESSEL) >> 24;
+
+       return 0;
 }
 
 static void dwmac1000_rx_watchdog(void __iomem *ioaddr, u32 riwt,

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c b/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
index 0d993f4b701c248a0f61caa4304c3fdfa5d6ae2e..ae473d85b7fb8529510c3e8ed9727cd75ae74e06 100644 (file)
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
@@ -336,8 +336,8 @@ static void dwmac4_dma_tx_chan_op_mode(void __iomem *ioaddr, int mode,
        writel(mtl_tx_op, ioaddr +  MTL_CHAN_TX_OP_MODE(channel));
 }
 
-static void dwmac4_get_hw_feature(void __iomem *ioaddr,
-                                 struct dma_features *dma_cap)
+static int dwmac4_get_hw_feature(void __iomem *ioaddr,
+                                struct dma_features *dma_cap)
 {
        u32 hw_cap = readl(ioaddr + GMAC_HW_FEATURE0);
 
@@ -400,6 +400,8 @@ static void dwmac4_get_hw_feature(void __iomem *ioaddr,
        dma_cap->frpbs = (hw_cap & GMAC_HW_FEAT_FRPBS) >> 11;
        dma_cap->frpsel = (hw_cap & GMAC_HW_FEAT_FRPSEL) >> 10;
        dma_cap->dvlan = (hw_cap & GMAC_HW_FEAT_DVLAN) >> 5;
+
+       return 0;
 }
 
 /* Enable/disable TSO feature and set MSS */

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_dma.c b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_dma.c
index 4af7271cea5613f359898993e3897b407da63cd9..07ef0ac725b3e9cbc7fef2c76b78d81f312c0779 100644 (file)
--- a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_dma.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_dma.c
@@ -356,8 +356,8 @@ static int dwxgmac2_dma_interrupt(void __iomem *ioaddr,
        return ret;
 }
 
-static void dwxgmac2_get_hw_feature(void __iomem *ioaddr,
-                                   struct dma_features *dma_cap)
+static int dwxgmac2_get_hw_feature(void __iomem *ioaddr,
+                                  struct dma_features *dma_cap)
 {
        u32 hw_cap;
 
@@ -425,6 +425,8 @@ static void dwxgmac2_get_hw_feature(void __iomem *ioaddr,
        dma_cap->frpes = (hw_cap & XGMAC_HWFEAT_FRPES) >> 11;
        dma_cap->frpbs = (hw_cap & XGMAC_HWFEAT_FRPPB) >> 9;
        dma_cap->frpsel = (hw_cap & XGMAC_HWFEAT_FRPSEL) >> 3;
+
+       return 0;
 }
 
 static void dwxgmac2_rx_watchdog(void __iomem *ioaddr, u32 riwt, u32 nchan)

diff --git a/drivers/net/ethernet/stmicro/stmmac/hwif.h b/drivers/net/ethernet/stmicro/stmmac/hwif.h
index 9010d881b12e58ac13e531cc7dfdaeeeca256f8c..59a1d8c00372112015a4ca9b3a0afddf6ca647ef 100644 (file)
--- a/drivers/net/ethernet/stmicro/stmmac/hwif.h
+++ b/drivers/net/ethernet/stmicro/stmmac/hwif.h
@@ -196,8 +196,8 @@ struct stmmac_dma_ops {
        int (*dma_interrupt) (void __iomem *ioaddr,
                              struct stmmac_extra_stats *x, u32 chan);
        /* If supported then get the optional core features */
-       void (*get_hw_feature)(void __iomem *ioaddr,
-                              struct dma_features *dma_cap);
+       int (*get_hw_feature)(void __iomem *ioaddr,
+                             struct dma_features *dma_cap);
        /* Program the HW RX Watchdog */
        void (*rx_watchdog)(void __iomem *ioaddr, u32 riwt, u32 number_chan);
        void (*set_tx_ring_len)(void __iomem *ioaddr, u32 len, u32 chan);
@@ -247,7 +247,7 @@ struct stmmac_dma_ops {
 #define stmmac_dma_interrupt_status(__priv, __args...) \
        stmmac_do_callback(__priv, dma, dma_interrupt, __args)
 #define stmmac_get_hw_feature(__priv, __args...) \
-       stmmac_do_void_callback(__priv, dma, get_hw_feature, __args)
+       stmmac_do_callback(__priv, dma, get_hw_feature, __args)
 #define stmmac_rx_watchdog(__priv, __args...) \
        stmmac_do_void_callback(__priv, dma, rx_watchdog, __args)
 #define stmmac_set_tx_ring_len(__priv, __args...) \