rapidio, powerpc/85xx: Add MChk handler for SRIO port

Add Machine Check exception handling into RapidIO port driver for
Freescale SoCs (MPC85xx).

Signed-off-by: Alexandre Bounine <alexandre.bounine@idt.com>
Tested-by: Thomas Moll <thomas.moll@sysgo.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Li Yang <leoli@freescale.com>
Cc: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 70 insertions, 4 deletions

diff --git a/arch/powerpc/sysdev/fsl_rio.c b/arch/powerpc/sysdev/fsl_rio.c
index 73d5f3e142ab..4646cc7aa93a 100644
--- a/arch/powerpc/sysdev/fsl_rio.c
+++ b/arch/powerpc/sysdev/fsl_rio.c
@@ -32,6 +32,8 @@
 #include <linux/kfifo.h>
 
 #include <asm/io.h>
+#include <asm/machdep.h>
+#include <asm/uaccess.h>
 
 #undef DEBUG_PW /* Port-Write debugging */
 
@@ -47,6 +49,8 @@
 #define RIO_ESCSR               0x158
 #define RIO_CCSR                0x15c
 #define RIO_LTLEDCSR            0x0608
+#define  RIO_LTLEDCSR_IER       0x80000000
+#define  RIO_LTLEDCSR_PRT       0x01000000
 #define RIO_LTLEECSR            0x060c
 #define RIO_EPWISR              0x10010
 #define RIO_ISR_AACR            0x10120
@@ -214,6 +218,54 @@ struct rio_priv {
         spinlock_t pw_fifo_lock;
 };
 
+#define __fsl_read_rio_config(x, addr, err, op)         \
+        __asm__ __volatile__(                           \
+                "1:     "op" %1,0(%2)\n"                \
+                "       eieio\n"                        \
+                "2:\n"                                  \
+                ".section .fixup,\"ax\"\n"              \
+                "3:     li %1,-1\n"                     \
+                "       li %0,%3\n"                     \
+                "       b 2b\n"                         \
+                ".section __ex_table,\"a\"\n"           \
+                "       .align 2\n"                     \
+                "       .long 1b,3b\n"                  \
+                ".text"                                 \
+                : "=r" (err), "=r" (x)                  \
+                : "b" (addr), "i" (-EFAULT), "0" (err))
+
+static void __iomem *rio_regs_win;
+
+static int (*saved_mcheck_exception)(struct pt_regs *regs);
+
+static int fsl_rio_mcheck_exception(struct pt_regs *regs)
+{
+        const struct exception_table_entry *entry = NULL;
+        unsigned long reason = (mfspr(SPRN_MCSR) & MCSR_MASK);
+
+        if (reason & MCSR_BUS_RBERR) {
+                reason = in_be32((u32 *)(rio_regs_win + RIO_LTLEDCSR));
+                if (reason & (RIO_LTLEDCSR_IER | RIO_LTLEDCSR_PRT)) {
+                        /* Check if we are prepared to handle this fault */
+                        entry = search_exception_tables(regs->nip);
+                        if (entry) {
+                                pr_debug("RIO: %s - MC Exception handled\n",
+                                         __func__);
+                                out_be32((u32 *)(rio_regs_win + RIO_LTLEDCSR),
+                                         0);
+                                regs->msr |= MSR_RI;
+                                regs->nip = entry->fixup;
+                                return 1;
+                        }
+                }
+        }
+
+        if (saved_mcheck_exception)
+                return saved_mcheck_exception(regs);
+        else
+                return cur_cpu_spec->machine_check(regs);
+}
+
 /**
  * fsl_rio_doorbell_send - Send a MPC85xx doorbell message
  * @mport: RapidIO master port info
@@ -314,6 +366,7 @@ fsl_rio_config_read(struct rio_mport *mport, int index, u16 destid,
 {
         struct rio_priv *priv = mport->priv;
         u8 *data;
+        u32 rval, err = 0;
 
         pr_debug
             ("fsl_rio_config_read: index %d destid %d hopcount %d offset %8.8x len %d\n",
@@ -324,17 +377,24 @@ fsl_rio_config_read(struct rio_mport *mport, int index, u16 destid,
         data = (u8 *) priv->maint_win + offset;
         switch (len) {
         case 1:
-                *val = in_8((u8 *) data);
+                __fsl_read_rio_config(rval, data, err, "lbz");
                 break;
         case 2:
-                *val = in_be16((u16 *) data);
+                __fsl_read_rio_config(rval, data, err, "lhz");
                 break;
         default:
-                *val = in_be32((u32 *) data);
+                __fsl_read_rio_config(rval, data, err, "lwz");
                 break;
         }
 
-        return 0;
+        if (err) {
+                pr_debug("RIO: cfg_read error %d for %x:%x:%x\n",
+                         err, destid, hopcount, offset);
+        }
+
+        *val = rval;
+
+        return err;
 }
 
 /**
@@ -1365,6 +1425,7 @@ int fsl_rio_setup(struct of_device *dev)
         rio_register_mport(port);
 
         priv->regs_win = ioremap(regs.start, regs.end - regs.start + 1);
+        rio_regs_win = priv->regs_win;
 
         /* Probe the master port phy type */
         ccsr = in_be32(priv->regs_win + RIO_CCSR);
@@ -1433,6 +1494,11 @@ int fsl_rio_setup(struct of_device *dev)
         fsl_rio_doorbell_init(port);
         fsl_rio_port_write_init(port);
 
+        saved_mcheck_exception = ppc_md.machine_check_exception;
+        ppc_md.machine_check_exception = fsl_rio_mcheck_exception;
+        /* Ensure that RFXE is set */
+        mtspr(SPRN_HID1, (mfspr(SPRN_HID1) | 0x20000));
+
         return 0;
 err:
         iounmap(priv->regs_win);