can: ifi: Check core revision upon probe

Older versions of the core are not compatible with the driver due
to various intrusive fixes of the core. Read out the VER register,
check the core revision bitfield and verify if the core in use is
new enough (rev 2.1 or newer) to work correctly with this driver.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Heiko Schocher <hs@denx.de>
Cc: Markus Marb <markus@marb.org>
Cc: Marc Kleine-Budde <mkl@pengutronix.de>
Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/drivers/net/can/ifi_canfd/ifi_canfd.c b/drivers/net/can/ifi_canfd/ifi_canfd.c
index 2772d05..9fd396c 100644 (file)
--- a/drivers/net/can/ifi_canfd/ifi_canfd.c
+++ b/drivers/net/can/ifi_canfd/ifi_canfd.c
@@ -136,6 +136,8 @@
 #define IFI_CANFD_SYSCLOCK                     0x50
 
 #define IFI_CANFD_VER                          0x54
+#define IFI_CANFD_VER_REV_MASK                 0xff
+#define IFI_CANFD_VER_REV_MIN_SUPPORTED                0x15
 
 #define IFI_CANFD_IP_ID                                0x58
 #define IFI_CANFD_IP_ID_VALUE                  0xD073CAFD
@@ -933,7 +935,7 @@ static int ifi_canfd_plat_probe(struct platform_device *pdev)
        struct resource *res;
        void __iomem *addr;
        int irq, ret;
-       u32 id;
+       u32 id, rev;
 
        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        addr = devm_ioremap_resource(dev, res);
@@ -947,6 +949,13 @@ static int ifi_canfd_plat_probe(struct platform_device *pdev)
                return -EINVAL;
        }
 
+       rev = readl(addr + IFI_CANFD_VER) & IFI_CANFD_VER_REV_MASK;
+       if (rev < IFI_CANFD_VER_REV_MIN_SUPPORTED) {
+               dev_err(dev, "This block is too old (rev %i), minimum supported is rev %i\n",
+                       rev, IFI_CANFD_VER_REV_MIN_SUPPORTED);
+               return -EINVAL;
+       }
+
        ndev = alloc_candev(sizeof(*priv), 1);
        if (!ndev)
                return -ENOMEM;