[bhnd] Initial bhnd(4) SPROM/NVRAM support.

This adds support for the NVRAM handling and the basic SPROM
hardware used on siba(4) and bcma(4) devices, including:

* SPROM directly attached to the PCI core, accessible via PCI configuration
  space.
* SPROM attached to later ChipCommon cores.
* SPROM variables vended from the parent SoC bus (e.g. via a directly-attached
  flash device).

Additional improvements to the NVRAM/SPROM interface will
be required, but this changeset stands alone as working
checkpoint.

Submitted by:	Landon Fuller <landonf@landonf.org>
Reviewed by:	Michael Zhilin <mizkha@gmail.com> (Broadcom MIPS support)
Differential Revision:	https://reviews.freebsd.org/D6196

1 files changed, 31 insertions, 20 deletions

diff --git a/sys/dev/bhnd/bhnd.c b/sys/dev/bhnd/bhnd.c
index 8b3c3788470e..3be15b259f22 100644
--- a/sys/dev/bhnd/bhnd.c
+++ b/sys/dev/bhnd/bhnd.c
@@ -58,11 +58,14 @@ __FBSDID("$FreeBSD$");
 #include <sys/rman.h>
 #include <machine/resource.h>
 
-#include "bhnd.h"
-#include "bhndvar.h"
+#include "nvram/bhnd_nvram.h"
 
+#include "bhnd_chipc_if.h"
 #include "bhnd_nvram_if.h"
 
+#include "bhnd.h"
+#include "bhndvar.h"
+
 MALLOC_DEFINE(M_BHND, "bhnd", "bhnd bus data structures");
 
 /**
@@ -386,23 +389,27 @@ bhnd_generic_is_region_valid(device_t dev, device_t child,
 static device_t
 find_nvram_child(device_t dev)
 {
-	device_t chipc, nvram;
+	device_t	chipc, nvram;
 
 	/* Look for a directly-attached NVRAM child */
-	nvram = device_find_child(dev, devclass_get_name(bhnd_nvram_devclass),
-	    -1);
-	if (nvram == NULL)
-		return (NULL);
+	nvram = device_find_child(dev, "bhnd_nvram", 0);
+	if (nvram != NULL)
+		return (nvram);
 
-	/* Further checks require a bhnd(4) bus */
+	/* Remaining checks are only applicable when searching a bhnd(4)
+	 * bus. */
 	if (device_get_devclass(dev) != bhnd_devclass)
 		return (NULL);
 
-	/* Look for a ChipCommon-attached OTP device */
+	/* Look for a ChipCommon device */
 	if ((chipc = bhnd_find_child(dev, BHND_DEVCLASS_CC, -1)) != NULL) {
-		/* Recursively search the ChipCommon device */
-		if ((nvram = find_nvram_child(chipc)) != NULL)
-			return (nvram);
+		bhnd_nvram_src_t src;
+
+		/* Query the NVRAM source and determine whether it's
+		 * accessible via the ChipCommon device */
+		src = BHND_CHIPC_NVRAM_SRC(chipc);
+		if (BHND_NVRAM_SRC_CC(src))
+			return (chipc);
 	}
 
 	/* Not found */
@@ -410,22 +417,26 @@ find_nvram_child(device_t dev)
 }
 
 /**
- * Default bhnd(4) bus driver implementation of BHND_BUS_READ_NVRAM_VAR().
+ * Default bhnd(4) bus driver implementation of BHND_BUS_GET_NVRAM_VAR().
+ * 
+ * This implementation searches @p dev for a usable NVRAM child device:
+ * - The first child device implementing the bhnd_nvram devclass is
+ *   returned, otherwise
+ * - If @p dev is a bhnd(4) bus, a ChipCommon core that advertises an
+ *   attached NVRAM source.
  * 
- * This implementation searches @p dev for a valid NVRAM device. If no NVRAM
- * child device is found on @p dev, the request is delegated to the
- * BHND_BUS_READ_NVRAM_VAR() method on the parent
- * of @p dev.
+ * If no usable child device is found on @p dev, the request is delegated to
+ * the BHND_BUS_GET_NVRAM_VAR() method on the parent of @p dev.
  */
 static int
-bhnd_generic_read_nvram_var(device_t dev, device_t child, const char *name,
+bhnd_generic_get_nvram_var(device_t dev, device_t child, const char *name,
     void *buf, size_t *size)
 {
 	device_t nvram;
 
 	/* Try to find an NVRAM device applicable to @p child */
 	if ((nvram = find_nvram_child(dev)) == NULL)
-		return (BHND_BUS_READ_NVRAM_VAR(device_get_parent(dev), child,
+		return (BHND_BUS_GET_NVRAM_VAR(device_get_parent(dev), child,
 		    name, buf, size));
 
 	return BHND_NVRAM_GETVAR(nvram, name, buf, size);
@@ -682,7 +693,7 @@ static device_method_t bhnd_methods[] = {
 	DEVMETHOD(bhnd_bus_get_probe_order,	bhnd_generic_get_probe_order),
 	DEVMETHOD(bhnd_bus_is_region_valid,	bhnd_generic_is_region_valid),
 	DEVMETHOD(bhnd_bus_is_hw_disabled,	bhnd_bus_generic_is_hw_disabled),
-	DEVMETHOD(bhnd_bus_read_nvram_var,	bhnd_generic_read_nvram_var),
+	DEVMETHOD(bhnd_bus_get_nvram_var,	bhnd_generic_get_nvram_var),
 	DEVMETHOD(bhnd_bus_read_1,		bhnd_read_1),
 	DEVMETHOD(bhnd_bus_read_2,		bhnd_read_2),
 	DEVMETHOD(bhnd_bus_read_4,		bhnd_read_4),