[PATCH net-next 2/8] nfp: nfpcore: add rtsym writing function

[Jakub Kicinski]

From: John Hurley <john.hur...@netronome.com>

Add an rtsym API function that combines the lookup of a symbol and the
writing of a value to it. Values can be written as unsigned 32 or 64 bits.

Signed-off-by: John Hurley <john.hur...@netronome.com>
Reviewed-by: Pieter Jansen van Vuuren <pieter.jansenvanvuu...@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicin...@netronome.com>
---
 .../ethernet/netronome/nfp/nfpcore/nfp_nffw.h |  2 +
 .../netronome/nfp/nfpcore/nfp_rtsym.c         | 43 +++++++++++++++++++
 2 files changed, 45 insertions(+)

diff --git a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_nffw.h 
b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_nffw.h
index c9724fb7ea4b..df599d5b6bb3 100644
--- a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_nffw.h
+++ b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_nffw.h
@@ -100,6 +100,8 @@ nfp_rtsym_lookup(struct nfp_rtsym_table *rtbl, const char 
*name);
 
 u64 nfp_rtsym_read_le(struct nfp_rtsym_table *rtbl, const char *name,
                      int *error);
+int nfp_rtsym_write_le(struct nfp_rtsym_table *rtbl, const char *name,
+                      u64 value);
 u8 __iomem *
 nfp_rtsym_map(struct nfp_rtsym_table *rtbl, const char *name, const char *id,
              unsigned int min_size, struct nfp_cpp_area **area);
diff --git a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_rtsym.c 
b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_rtsym.c
index 46107aefad1c..9e34216578da 100644
--- a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_rtsym.c
+++ b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_rtsym.c
@@ -286,6 +286,49 @@ u64 nfp_rtsym_read_le(struct nfp_rtsym_table *rtbl, const 
char *name,
        return val;
 }
 
+/**
+ * nfp_rtsym_write_le() - Write an unsigned scalar value to a symbol
+ * @rtbl:      NFP RTsym table
+ * @name:      Symbol name
+ * @value:     Value to write
+ *
+ * Lookup a symbol and write a value to it. Symbol can be 4 or 8 bytes in size.
+ * If 4 bytes then the lower 32-bits of 'value' are used. Value will be
+ * written as simple little-endian unsigned value.
+ *
+ * Return: 0 on success or error code.
+ */
+int nfp_rtsym_write_le(struct nfp_rtsym_table *rtbl, const char *name,
+                      u64 value)
+{
+       const struct nfp_rtsym *sym;
+       int err;
+       u32 id;
+
+       sym = nfp_rtsym_lookup(rtbl, name);
+       if (!sym)
+               return -ENOENT;
+
+       id = NFP_CPP_ISLAND_ID(sym->target, NFP_CPP_ACTION_RW, 0, sym->domain);
+
+       switch (sym->size) {
+       case 4:
+               err = nfp_cpp_writel(rtbl->cpp, id, sym->addr, value);
+               break;
+       case 8:
+               err = nfp_cpp_writeq(rtbl->cpp, id, sym->addr, value);
+               break;
+       default:
+               nfp_err(rtbl->cpp,
+                       "rtsym '%s' unsupported or non-scalar size: %lld\n",
+                       name, sym->size);
+               err = -EINVAL;
+               break;
+       }
+
+       return err;
+}
+
 u8 __iomem *
 nfp_rtsym_map(struct nfp_rtsym_table *rtbl, const char *name, const char *id,
              unsigned int min_size, struct nfp_cpp_area **area)
-- 
2.17.0