[PATCH] bsps/shared/ofw: Implement RTEMS OFW interface

Chris Johns chrisj at rtems.org
Sun Aug 16 22:19:26 UTC 2020


On 16/8/20 11:19 pm, Niteesh G. S. wrote:
> 
> On Sun, Aug 16, 2020 at 2:25 PM Chris Johns <chrisj at rtems.org
> <mailto:chrisj at rtems.org>> wrote:
> 
>     On 16/8/20 4:49 am, G S Niteesh Babu wrote:
>     > ---
> 
>     > +
>     > +#ifdef HAVE_CONFIG_H
>     > +#include "config.h"
>     > +#endif
>     > +
>     > +#include <bsp/fdt.h>
>     > +#include <sys/param.h>
>     > +#include <ofw/ofw.h>
>     > +#include <libfdt.h>
>     > +#include <assert.h>
>     > +#include <rtems/sysinit.h>
>     > +
>     > +const void *fdtp = NULL;
>     > +
>     > +static phandle_t rtems_fdt_offset_to_phandle( int offset )
>     > +{
>     > +  if (offset < 0) {
>     > +    return 0;
>     > +  }
>     > +
>     > +  return (phandle_t)offset + fdt_off_dt_struct(fdtp);
>     > +}
>     > +
>     > +static int rtems_fdt_phandle_to_offset( phandle_t handle )
>     > +{
>     > +  int off;
>     > +  int fdt_off;
>     > +
>     > +  off = (int) handle;
>     > +  fdt_off = fdt_off_dt_struct(fdtp);
>     > +
>     > +  if (off < fdt_off) {
>     > +    return -1;
>     > +
>     > +  }
>     > +
>     > +  return off - fdt_off;
>     > +}
>     > +
>     > +static void rtems_ofw_init( void ) {
>     > +  int rv;
>     > +  const void *fdt;
>     > + 
>     > +  fdt = bsp_fdt_get();
>     > +
>     > +  rv = fdt_check_header(fdt);
>     > +
>     > +  /*
>     > +   * Is assert a good option to handle error?
>     > +   * AFIAK there is no other way to recover from invalid FDT.
>     > +   * On providing an invalid FDT most driver's will fail/crash anyway.
>     > +   */
> 
>     If you want to fail with an error I suggest a documented internal error. I
>     however would prefer we fail in degraded manner but I understand this may not be
>     possible.
> 
> 
> During the initial discussion, we discussed adding a new error code in case of an
> invalid FDT, something like BSP_INVALID_FDT. I had also sent a patch but then we
> decided not to add one(for some reason that I don't remember). Instead, use
> RTEMS_NOT_CONFIGURED. This has also been used in my previous OFW patch.

I am sorry I missed the discussion or I would have commented. Currently the FDT
support in RTEMS is hostile. If you build a u-boot image and forget to add FDT
support added you get a low level crash dump and that is unfriendly. I woud like
to this changed.

> So should we add a new error code like BSP_INVALID_FDT and fatal exit or just
> use RTEMS_NOT_CONIGURED like the previous patch?

Not configured is fine with me.

Chris
> 
> 
>     > +  assert(rv == 0);
> 
>     I would prefer we did not make this code dependent on -DNDEBUG.
> 
>     Chris
> 
>     > +
>     > +  fdtp = fdt;
>     > +}
>     > +
>     > +RTEMS_SYSINIT_ITEM(
>     > +  rtems_ofw_init,
>     > +  RTEMS_SYSINIT_BSP_PRE_DRIVERS,
>     > +  RTEMS_SYSINIT_ORDER_FIRST
>     > +);
>     > +
>     > +phandle_t rtems_ofw_peer( phandle_t node )
>     > +{
>     > +  int offset;
>     > +
>     > +  if (node == 0) {
>     > +    int root = fdt_path_offset(fdtp, "/");
>     > +    return rtems_fdt_offset_to_phandle(root);
>     > +  }
>     > +
>     > +  offset = rtems_fdt_phandle_to_offset(node);
>     > +  if (offset < 0) {
>     > +    return 0;
>     > +  }
>     > +
>     > +  offset = fdt_next_subnode(fdtp, offset);
>     > +  return rtems_fdt_offset_to_phandle(offset);
>     > +}
>     > +
>     > +phandle_t rtems_ofw_child( phandle_t node )
>     > +{
>     > +  int offset;
>     > +
>     > +  offset = rtems_fdt_phandle_to_offset(node);
>     > +
>     > +  if (offset < 0) {
>     > +    return 0;
>     > +  }
>     > +
>     > +  offset = fdt_first_subnode(fdtp, offset);
>     > +  return rtems_fdt_offset_to_phandle(offset);
>     > +}
>     > +
>     > +phandle_t rtems_ofw_parent( phandle_t node )
>     > +{
>     > +  int offset;
>     > +
>     > +  offset = rtems_fdt_phandle_to_offset(node);
>     > +
>     > +  if (offset < 0) {
>     > +    return 0;
>     > +  }
>     > +
>     > +  offset = fdt_parent_offset(fdtp, offset);
>     > +  return rtems_fdt_offset_to_phandle(offset);
>     > +}
>     > +
>     > +size_t rtems_ofw_get_prop_len(
>     > +  phandle_t node,
>     > +  const char *propname
>     > +)
>     > +{
>     > +  int offset;
>     > +  int len;
>     > +  const void *prop;
>     > +
>     > +  offset = rtems_fdt_phandle_to_offset(node);
>     > +
>     > +  if (offset < 0) {
>     > +    return -1;
>     > +  }
>     > +
>     > +  prop = fdt_getprop(fdtp, offset, propname, &len);
>     > +
>     > +  if (prop == NULL && strcmp(propname, "name") == 0) {
>     > +    fdt_get_name(fdtp, offset, &len);
>     > +    return len + 1;
>     > +  }
>     > +
>     > +  if (prop == NULL && strcmp(propname, "/chosen") == 0) {
>     > +    if (strcmp(propname, "fdtbootcpu") == 0)
>     > +      return sizeof(pcell_t);
>     > +    if (strcmp(propname, "fdtmemreserv") == 0)
>     > +      return 2 * sizeof(uint64_t) * fdt_num_mem_rsv(fdtp);
>     > +  }
>     > +
>     > +  if (prop == NULL) {
>     > +    return -1;
>     > +  }
>     > +
>     > +  return len;
>     > +}
>     > +
>     > +size_t rtems_ofw_get_prop(
>     > +  phandle_t    node,
>     > +  const char  *propname,
>     > +  void        *buf,
>     > +  size_t       bufsize
>     > +)
>     > +{
>     > +  int offset;
>     > +  int len;
>     > +  const void *prop;
>     > +
>     > +  offset = rtems_fdt_phandle_to_offset(node);
>     > +
>     > +  if (offset < 0) {
>     > +    return -1;
>     > +  }
>     > +
>     > +  prop = fdt_getprop(fdtp, offset, propname, &len);
>     > +
>     > +  if (prop == NULL && strcmp(propname, "name") == 0) {
>     > +    fdt_get_name(fdtp, offset, &len);
>     > +    return len + 1;
>     > +  }
>     > +
>     > +  if (prop == NULL && strcmp(propname, "/chosen") == 0) {
>     > +    if (strcmp(propname, "fdtbootcpu") == 0)
>     > +      return sizeof(pcell_t);
>     > +    if (strcmp(propname, "fdtmemreserv") == 0)
>     > +      return 2 * sizeof(uint64_t) * fdt_num_mem_rsv(fdtp);
>     > +  }
>     > +
>     > +  if (prop == NULL) {
>     > +    return -1;
>     > +  }
>     > +
>     > +  bcopy(prop, buf, MIN(len, bufsize));
>     > +
>     > +  return len;
>     > +}
>     > +
>     > +size_t rtems_ofw_get_enc_prop(
>     > +  phandle_t    node,
>     > +  const char  *prop,
>     > +  pcell_t     *buf,
>     > +  size_t       len
>     > +)
>     > +{
>     > +  size_t rv;
>     > +
>     > +  assert(len % 4 == 0);
>     > +  rv = rtems_ofw_get_prop(node, prop, buf, len);
>     > +
>     > +  if (rv < 0) {
>     > +    return rv;
>     > +  }
>     > +
>     > +  for (int i = 0; i < (len / 4); i++) {
>     > +    buf[i] = fdt32_to_cpu(buf[i]);
>     > +  }
>     > +
>     > +  return rv;
>     > +}
>     > +
>     > +int rtems_ofw_has_prop(
>     > +  phandle_t    node,
>     > +  const char  *propname
>     > +)
>     > +{
>     > +  size_t rv;
>     > +
>     > +  rv = rtems_ofw_get_prop_len(node, propname);
>     > +  return rv >= 0 ? 1 : 0;
>     > +}
>     > +
>     > +size_t rtems_ofw_search_prop(
>     > +  phandle_t    node,
>     > +  const char  *propname,
>     > +  void        *buf,
>     > +  size_t       len
>     > +)
>     > +{
>     > +  size_t rv;
>     > +
>     > +  for (; node != 0; node = rtems_ofw_parent(node)) {
>     > +    if ((rv = rtems_ofw_get_prop(node, propname, buf, len) != -1)) {
>     > +      return rv;
>     > +    }
>     > +  }
>     > +
>     > +  return -1;
>     > +}
>     > +
>     > +size_t rtems_ofw_search_enc_prop(
>     > +  phandle_t    node,
>     > +  const char  *propname,
>     > +  pcell_t     *buf,
>     > +  size_t       len
>     > +)
>     > +{
>     > +  size_t rv;
>     > +
>     > +  for (; node != 0; node = rtems_ofw_parent(node)) {
>     > +    if ((rv = rtems_ofw_get_enc_prop(node, propname, buf, len) != -1)) {
>     > +      return rv;
>     > +    }
>     > +  }
>     > +
>     > +  return -1;
>     > +}
>     > +
>     > +size_t rtems_ofw_get_prop_alloc(
>     > +  phandle_t    node,
>     > +  const char  *propname,
>     > +  void       **buf
>     > +)
>     > +{
>     > +  size_t len;
>     > +
>     > +  if ((len = rtems_ofw_get_prop_len(node, propname)) == -1) {
>     > +    return -1;
>     > +  }
>     > +
>     > +  *buf = NULL;
>     > +
>     > +  if (len > 0) {
>     > +    *buf = malloc(len);
>     > +
>     > +    if (rtems_ofw_get_prop(node, propname, *buf, len) == -1) {
>     > +      rtems_ofw_free(buf);
>     > +      *buf = NULL;
>     > +      return -1;
>     > +    }
>     > +  }
>     > +
>     > +  return len;
>     > +}
>     > +
>     > +size_t rtems_ofw_get_prop_alloc_multi(
>     > +  phandle_t    node,
>     > +  const char  *propname,
>     > +  int          elsz,
>     > +  void       **buf
>     > +)
>     > +{
>     > +  size_t len;
>     > +
>     > +  if ((len = rtems_ofw_get_prop_len(node, propname)) == -1 ||
>     > +      (len % elsz != 0)) {
>     > +    return -1;
>     > +  }
>     > +
>     > +  *buf = NULL;
>     > +
>     > +  if (len > 0) {
>     > +    *buf = malloc(len);
>     > +
>     > +    if (rtems_ofw_get_prop(node, propname, *buf, len) == -1) {
>     > +      rtems_ofw_free(buf);
>     > +      *buf = NULL;
>     > +      return -1;
>     > +    }
>     > +  }
>     > +
>     > +  return (len / elsz);
>     > +}
>     > +
>     > +size_t rtems_ofw_get_enc_prop_alloc(
>     > +  phandle_t    node,
>     > +  const char  *propname,
>     > +  void       **buf
>     > +)
>     > +{
>     > +  size_t len;
>     > +
>     > +  if ((len = rtems_ofw_get_prop_len(node, propname)) == -1) {
>     > +    return -1;
>     > +  }
>     > +
>     > +  *buf = NULL;
>     > +
>     > +  if (len > 0) {
>     > +    *buf = malloc(len);
>     > +
>     > +    if (rtems_ofw_get_enc_prop(node, propname, *buf, len) == -1) {
>     > +      rtems_ofw_free(buf);
>     > +      *buf = NULL;
>     > +      return -1;
>     > +    }
>     > +  }
>     > +
>     > +  return len;
>     > +}
>     > +
>     > +size_t rtems_ofw_get_enc_prop_alloc_multi(
>     > +  phandle_t     node,
>     > +  const char   *propname,
>     > +  int           elsz,
>     > +  void        **buf
>     > +)
>     > +{
>     > +  size_t len;
>     > +
>     > +  if ((len = rtems_ofw_get_prop_len(node, propname)) == -1 ||
>     > +      (len % elsz != 0)) {
>     > +    return -1;
>     > +  }
>     > +
>     > +  *buf = NULL;
>     > +
>     > +  if (len > 0) {
>     > +    *buf = malloc(len);
>     > +
>     > +    if (rtems_ofw_get_enc_prop(node, propname, *buf, len) == -1) {
>     > +      rtems_ofw_free(buf);
>     > +      *buf = NULL;
>     > +      return -1;
>     > +    }
>     > +  }
>     > +
>     > +  return (len / elsz);
>     > +}
>     > +
>     > +void rtems_ofw_free( void *buf )
>     > +{
>     > +  free(buf);
>     > +}
>     > +
>     > +int rtems_ofw_next_prop(
>     > +  phandle_t    node,
>     > +  const char  *previous,
>     > +  char        *buf,
>     > +  size_t       len
>     > +)
>     > +{
>     > +  const void *name;
>     > +  const void *prop;
>     > +  int offset;
>     > +
>     > +  offset = rtems_fdt_phandle_to_offset(node);
>     > +
>     > +  if (offset < 0) {
>     > +    return -1;
>     > +  }
>     > +
>     > +  if (previous == NULL) {
>     > +    offset = fdt_first_property_offset(fdtp, offset);
>     > +  } else {
>     > +    fdt_for_each_property_offset(offset, fdtp, offset) {
>     > +      prop = fdt_getprop_by_offset(fdtp, offset, (const char **)&name, NULL);
>     > +      if (prop == NULL)
>     > +        return -1;
>     > +
>     > +      if (strcmp(previous, name) != 0)
>     > +        continue;
>     > +
>     > +      offset = fdt_next_property_offset(fdtp, offset);
>     > +      break;
>     > +    }
>     > +  }
>     > +
>     > +  if (offset < 0)
>     > +    return 0;
>     > +
>     > +  prop = fdt_getprop_by_offset(fdtp, offset, (const char **)&name, &offset);
>     > +  if (prop == NULL)
>     > +    return -1;
>     > +
>     > +  strncpy(buf, name, len);
>     > +
>     > +  return 1;
>     > +}
>     > +
>     > +int rtems_ofw_set_prop(
>     > +  phandle_t    node,
>     > +  const char  *name,
>     > +  const void  *buf,
>     > +  size_t       len
>     > +)
>     > +{
>     > +  int offset;
>     > +
>     > +  offset = rtems_fdt_phandle_to_offset(node);
>     > +
>     > +  if (offset < 0)
>     > +    return -1;
>     > +
>     > +  if (fdt_setprop_inplace(fdtp, offset, name, buf, len) != 0)
>     > +    return (fdt_setprop(fdtp, offset, name, buf, len));
>     > +
>     > +  return 0;
>     > +}
>     > +
>     > +phandle_t rtems_ofw_find_device( const char *path )
>     > +{
>     > +  int offset;
>     > +
>     > +  offset = fdt_path_offset(fdtp, path);
>     > +  if (offset < 0)
>     > +    return -1;
>     > +
>     > +  return rtems_fdt_offset_to_phandle(offset);
>     > +}
>     > +
>     > +static phandle_t rtems_ofw_get_effective_phandle(
>     > +  phandle_t node,
>     > +  phandle_t xref
>     > +)
>     > +{
>     > +  phandle_t child;
>     > +  phandle_t ref;
>     > +
>     > +  for (child = rtems_ofw_child(node); child != 0; child =
>     rtems_ofw_peer(node)) {
>     > +    ref = rtems_ofw_get_effective_phandle(child, xref);
>     > +    if (ref != -1)
>     > +      return ref;
>     > +
>     > +    if (rtems_ofw_get_enc_prop(child, "phandle", &ref, sizeof(ref)) == -1 &&
>     > +        rtems_ofw_get_enc_prop(child, "ibm,phandle", &ref, sizeof(ref))
>     == -1 &&
>     > +        rtems_ofw_get_enc_prop(child, "linux,phandle", &ref, sizeof(ref))
>     == -1
>     > +    ) {
>     > +      continue;
>     > +    }
>     > +
>     > +    if (ref == xref)
>     > +      return child;
>     > +  }
>     > +
>     > +  return -1;
>     > +}
>     > +
>     > +phandle_t rtems_ofw_node_from_xref( phandle_t xref )
>     > +{
>     > +  phandle_t node;
>     > +
>     > +  if ((node = rtems_ofw_get_effective_phandle(rtems_ofw_peer(0), xref))
>     == -1)
>     > +    return xref;
>     > +
>     > +  return node;
>     > +}
>     > +
>     > +phandle_t rtems_ofw_xref_from_node( phandle_t node )
>     > +{
>     > +  phandle_t ref;
>     > +
>     > +    if (rtems_ofw_get_enc_prop(node, "phandle", &ref, sizeof(ref)) == -1 &&
>     > +        rtems_ofw_get_enc_prop(node, "ibm,phandle", &ref, sizeof(ref)) ==
>     -1 &&
>     > +        rtems_ofw_get_enc_prop(node, "linux,phandle", &ref, sizeof(ref))
>     == -1)
>     > +    {
>     > +      return node;
>     > +    }
>     > +
>     > +    return ref;
>     > +}
>     > +
>     > +phandle_t rtems_ofw_instance_to_package( ihandle_t instance )
>     > +{
>     > +  return rtems_ofw_node_from_xref(instance);
>     > +}
>     > +
>     > +size_t rtems_ofw_package_to_path(
>     > +  phandle_t   node,
>     > +  char       *buf,
>     > +  size_t      len
>     > +)
>     > +{
>     > +  int offset;
>     > +  int rv;
>     > +
>     > +  offset = rtems_fdt_phandle_to_offset(node);
>     > +
>     > +  rv = fdt_get_path(fdtp, offset, buf, len);
>     > +  if (rv != 0)
>     > +    return -1;
>     > +
>     > +  return rv;
>     > +}
>     > +
>     > +size_t rtems_ofw_instance_to_path(
>     > +  ihandle_t  instance,
>     > +  char      *buf,
>     > +  size_t     len
>     > +)
>     > +{
>     > +  int offset;
>     > +  int rv;
>     > +
>     > +  offset = rtems_ofw_instance_to_package(instance);
>     > +  offset = rtems_fdt_phandle_to_offset(offset);
>     > +
>     > +  rv = fdt_get_path(fdtp, offset, buf, len);
>     > +  if (rv != 0)
>     > +    return -1;
>     > +
>     > +  return rv;
>     > +}
>     > +
>     > +int rtems_ofw_get_reg(
>     > +  phandle_t              node,
>     > +  rtems_ofw_memory_area *buf,
>     > +  size_t                 size
>     > +)
>     > +{
>     > +  int len;
>     > +  int offset;
>     > +  int nranges;
>     > +  int nregs;
>     > +  phandle_t parent;
>     > +  rtems_ofw_ranges range;
>     > +  const rtems_ofw_ranges *ptr;
>     > +
>     > +  len = rtems_ofw_get_enc_prop(node, "reg", (pcell_t *)buf, size);
>     > +  if (len <= 0) {
>     > +    return len;
>     > +  }
>     > +
>     > +  nregs = MIN(len, size) / sizeof(rtems_ofw_memory_area);
>     > +
>     > +  for (parent = rtems_ofw_parent(node); parent > 0;
>     > +      parent = rtems_ofw_parent(parent)) {
>     > +
>     > +    offset = rtems_fdt_phandle_to_offset(parent);
>     > +    ptr = fdt_getprop(fdtp, offset, "ranges", &len);
>     > +
>     > +    if (len < 0) {
>     > +      break;
>     > +    }
>     > +
>     > +    nranges = len / sizeof(rtems_ofw_ranges);
>     > +
>     > +    offset = 0;
>     > +    for (int i=0; i < nregs; i++) {
>     > +      for (int j=0; j < nranges; j++) {
>     > +       
>     > +        range.parent_bus = fdt32_to_cpu(ptr[j].parent_bus);
>     > +        range.child_bus = fdt32_to_cpu(ptr[j].child_bus);
>     > +        range.size = fdt32_to_cpu(ptr[j].size);
>     > +
>     > +        if (buf[i].start >= range.child_bus &&
>     > +            buf[i].start < range.child_bus + range.size) {
>     > +          offset = range.parent_bus - range.child_bus;
>     > +          break;
>     > +        }
>     > +
>     > +      }
>     > +      buf[i].start += offset;
>     > +    }
>     > +  }
>     > +
>     > +  return nregs;
>     > +}
>     > +
>     > +int rtems_ofw_get_interrupts(
>     > +  phandle_t node,
>     > +  void     *buf,
>     > +  size_t    size
>     > +)
>     > +{
>     > +  int rv;
>     > +
>     > +  rv = rtems_ofw_get_enc_prop(node, "interrupts", buf, size);
>     > +  return rv;
>     > +}
>     > +
>     > +bool rtems_ofw_node_status( phandle_t node )
>     > +{
>     > +  int len;
>     > +  const char buf[10];
>     > +
>     > +  len = rtems_ofw_get_prop(node, "status", &buf[0], sizeof(buf));
>     > +  if ((len == -1) ||
>     > +      (strncmp(buf, "okay", MIN(5, len)) == 0) ||
>     > +      (strncmp(buf, "ok", MIN(3, len)) == 0)) {
>     > +      return true;
>     > +  }
>     > +
>     > +  return false;
>     > +}
>     > diff --git a/spec/build/bsps/obj.yml b/spec/build/bsps/obj.yml
>     > index 8809238057..141ba25f5e 100644
>     > --- a/spec/build/bsps/obj.yml
>     > +++ b/spec/build/bsps/obj.yml
>     > @@ -24,6 +24,9 @@ install:
>     >    - bsps/include/bsp/u-boot.h
>     >    - bsps/include/bsp/uart-output-char.h
>     >    - bsps/include/bsp/utility.h
>     > +- destination: ${BSP_INCLUDEDIR}/ofw
>     > +  source:
>     > +  - bsps/include/ofw/ofw.h
>     >  - destination: ${BSP_INCLUDEDIR}/libchip
>     >    source:
>     >    - bsps/include/libchip/am29lv160.h
>     > @@ -104,4 +107,5 @@ source:
>     >  - bsps/shared/dev/serial/z85c30_reg.c
>     >  - bsps/shared/start/bootcard.c
>     >  - bsps/shared/rtems-version.c
>     > +- bsps/shared/ofw/ofw.c
>     >  type: build
>     >
> 


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