EDAC, pnd2: Build in a minimal sideband driver for Apollo Lake

I've been waing a long time for the generic sideband driver to
appear. Patience has run out, so include the minimum here to
just read registers.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Cc: Aristeu Rozanski <arozansk@redhat.com>
Cc: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Cc: Patrick Geary <patrickg@supermicro.com>
Cc: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/20170803210536.5662-1-tony.luck@intel.com
Signed-off-by: Borislav Petkov <bp@suse.de>

diff --git a/drivers/edac/pnd2_edac.c b/drivers/edac/pnd2_edac.c
index 8e599490f6dec2e1c1002742817bd61ded9ecc69..a3180a87ff9638d50598f6e806771adffc826bb6 100644 (file)
--- a/drivers/edac/pnd2_edac.c
+++ b/drivers/edac/pnd2_edac.c
@@ -129,42 +129,66 @@ static struct mem_ctl_info *pnd2_mci;
 #define GET_BITFIELD(v, lo, hi)        (((v) & GENMASK_ULL(hi, lo)) >> (lo))
 #define U64_LSHIFT(val, s)     ((u64)(val) << (s))
 
-#ifdef CONFIG_X86_INTEL_SBI_APL
-#include "linux/platform_data/sbi_apl.h"
-static int sbi_send(int port, int off, int op, u32 *data)
+/*
+ * On Apollo Lake we access memory controller registers via a
+ * side-band mailbox style interface in a hidden PCI device
+ * configuration space.
+ */
+static struct pci_bus  *p2sb_bus;
+#define P2SB_DEVFN     PCI_DEVFN(0xd, 0)
+#define P2SB_ADDR_OFF  0xd0
+#define P2SB_DATA_OFF  0xd4
+#define P2SB_STAT_OFF  0xd8
+#define P2SB_ROUT_OFF  0xda
+#define P2SB_EADD_OFF  0xdc
+#define P2SB_HIDE_OFF  0xe1
+
+#define P2SB_BUSY      1
+
+#define P2SB_READ(size, off, ptr) \
+       pci_bus_read_config_##size(p2sb_bus, P2SB_DEVFN, off, ptr)
+#define P2SB_WRITE(size, off, val) \
+       pci_bus_write_config_##size(p2sb_bus, P2SB_DEVFN, off, val)
+
+static bool p2sb_is_busy(u16 *status)
 {
-       struct sbi_apl_message sbi_arg;
-       int ret, read = 0;
+       P2SB_READ(word, P2SB_STAT_OFF, status);
 
-       memset(&sbi_arg, 0, sizeof(sbi_arg));
+       return !!(*status & P2SB_BUSY);
+}
 
-       if (op == 0 || op == 4 || op == 6)
-               read = 1;
-       else
-               sbi_arg.data = *data;
+static int _apl_rd_reg(int port, int off, int op, u32 *data)
+{
+       int retries = 0xff, ret;
+       u16 status;
+
+       P2SB_WRITE(byte, P2SB_HIDE_OFF, 0);
+
+       if (p2sb_is_busy(&status)) {
+               ret = -EAGAIN;
+               goto out;
+       }
 
-       sbi_arg.opcode = op;
-       sbi_arg.port_address = port;
-       sbi_arg.register_offset = off;
-       ret = sbi_apl_commit(&sbi_arg);
-       if (ret || sbi_arg.status)
-               edac_dbg(2, "sbi_send status=%d ret=%d data=%x\n",
-                                sbi_arg.status, ret, sbi_arg.data);
+       P2SB_WRITE(dword, P2SB_ADDR_OFF, (port << 24) | off);
+       P2SB_WRITE(dword, P2SB_DATA_OFF, 0);
+       P2SB_WRITE(dword, P2SB_EADD_OFF, 0);
+       P2SB_WRITE(word, P2SB_ROUT_OFF, 0);
+       P2SB_WRITE(word, P2SB_STAT_OFF, (op << 8) | P2SB_BUSY);
 
-       if (ret == 0)
-               ret = sbi_arg.status;
+       while (p2sb_is_busy(&status)) {
+               if (retries-- == 0) {
+                       ret = -EBUSY;
+                       goto out;
+               }
+       }
 
-       if (ret == 0 && read)
-               *data = sbi_arg.data;
+       P2SB_READ(dword, P2SB_DATA_OFF, data);
+       ret = (status >> 1) & 0x3;
+out:
+       P2SB_WRITE(byte, P2SB_HIDE_OFF, 1);
 
        return ret;
 }
-#else
-static int sbi_send(int port, int off, int op, u32 *data)
-{
-       return -EUNATCH;
-}
-#endif
 
 static int apl_rd_reg(int port, int off, int op, void *data, size_t sz, char *name)
 {
@@ -173,10 +197,10 @@ static int apl_rd_reg(int port, int off, int op, void *data, size_t sz, char *na
        edac_dbg(2, "Read %s port=%x off=%x op=%x\n", name, port, off, op);
        switch (sz) {
        case 8:
-               ret = sbi_send(port, off + 4, op, (u32 *)(data + 4));
+               ret = _apl_rd_reg(port, off + 4, op, (u32 *)(data + 4));
                /* fall through */
        case 4:
-               ret |= sbi_send(port, off, op, (u32 *)data);
+               ret |= _apl_rd_reg(port, off, op, (u32 *)data);
                pnd2_printk(KERN_DEBUG, "%s=%x%08x ret=%d\n", name,
                                        sz == 8 ? *((u32 *)(data + 4)) : 0, *((u32 *)data), ret);
                break;
@@ -1515,6 +1539,12 @@ static int __init pnd2_init(void)
 
        ops = (struct dunit_ops *)id->driver_data;
 
+       if (ops->type == APL) {
+               p2sb_bus = pci_find_bus(0, 0);
+               if (!p2sb_bus)
+                       return -ENODEV;
+       }
+
        /* Ensure that the OPSTATE is set correctly for POLL or NMI */
        opstate_init();