diff options
Diffstat (limited to 'drivers/net/dsa/sja1105/sja1105_dynamic_config.c')
| -rw-r--r-- | drivers/net/dsa/sja1105/sja1105_dynamic_config.c | 92 |
1 files changed, 92 insertions, 0 deletions
diff --git a/drivers/net/dsa/sja1105/sja1105_dynamic_config.c b/drivers/net/dsa/sja1105/sja1105_dynamic_config.c index 56c83b9d52e4..3acd48615981 100644 --- a/drivers/net/dsa/sja1105/sja1105_dynamic_config.c +++ b/drivers/net/dsa/sja1105/sja1105_dynamic_config.c @@ -3,6 +3,98 @@ */ #include "sja1105.h" +/* In the dynamic configuration interface, the switch exposes a register-like + * view of some of the static configuration tables. + * Many times the field organization of the dynamic tables is abbreviated (not + * all fields are dynamically reconfigurable) and different from the static + * ones, but the key reason for having it is that we can spare a switch reset + * for settings that can be changed dynamically. + * + * This file creates a per-switch-family abstraction called + * struct sja1105_dynamic_table_ops and two operations that work with it: + * - sja1105_dynamic_config_write + * - sja1105_dynamic_config_read + * + * Compared to the struct sja1105_table_ops from sja1105_static_config.c, + * the dynamic accessors work with a compound buffer: + * + * packed_buf + * + * | + * V + * +-----------------------------------------+------------------+ + * | ENTRY BUFFER | COMMAND BUFFER | + * +-----------------------------------------+------------------+ + * + * <----------------------- packed_size ------------------------> + * + * The ENTRY BUFFER may or may not have the same layout, or size, as its static + * configuration table entry counterpart. When it does, the same packing + * function is reused (bar exceptional cases - see + * sja1105pqrs_dyn_l2_lookup_entry_packing). + * + * The reason for the COMMAND BUFFER being at the end is to be able to send + * a dynamic write command through a single SPI burst. By the time the switch + * reacts to the command, the ENTRY BUFFER is already populated with the data + * sent by the core. + * + * The COMMAND BUFFER is always SJA1105_SIZE_DYN_CMD bytes (one 32-bit word) in + * size. + * + * Sometimes the ENTRY BUFFER does not really exist (when the number of fields + * that can be reconfigured is small), then the switch repurposes some of the + * unused 32 bits of the COMMAND BUFFER to hold ENTRY data. + * + * The key members of struct sja1105_dynamic_table_ops are: + * - .entry_packing: A function that deals with packing an ENTRY structure + * into an SPI buffer, or retrieving an ENTRY structure + * from one. + * The @packed_buf pointer it's given does always point to + * the ENTRY portion of the buffer. + * - .cmd_packing: A function that deals with packing/unpacking the COMMAND + * structure to/from the SPI buffer. + * It is given the same @packed_buf pointer as .entry_packing, + * so most of the time, the @packed_buf points *behind* the + * COMMAND offset inside the buffer. + * To access the COMMAND portion of the buffer, the function + * knows its correct offset. + * Giving both functions the same pointer is handy because in + * extreme cases (see sja1105pqrs_dyn_l2_lookup_entry_packing) + * the .entry_packing is able to jump to the COMMAND portion, + * or vice-versa (sja1105pqrs_l2_lookup_cmd_packing). + * - .access: A bitmap of: + * OP_READ: Set if the hardware manual marks the ENTRY portion of the + * dynamic configuration table buffer as R (readable) after + * an SPI read command (the switch will populate the buffer). + * OP_WRITE: Set if the manual marks the ENTRY portion of the dynamic + * table buffer as W (writable) after an SPI write command + * (the switch will read the fields provided in the buffer). + * OP_DEL: Set if the manual says the VALIDENT bit is supported in the + * COMMAND portion of this dynamic config buffer (i.e. the + * specified entry can be invalidated through a SPI write + * command). + * OP_SEARCH: Set if the manual says that the index of an entry can + * be retrieved in the COMMAND portion of the buffer based + * on its ENTRY portion, as a result of a SPI write command. + * Only the TCAM-based FDB table on SJA1105 P/Q/R/S supports + * this. + * - .max_entry_count: The number of entries, counting from zero, that can be + * reconfigured through the dynamic interface. If a static + * table can be reconfigured at all dynamically, this + * number always matches the maximum number of supported + * static entries. + * - .packed_size: The length in bytes of the compound ENTRY + COMMAND BUFFER. + * Note that sometimes the compound buffer may contain holes in + * it (see sja1105_vlan_lookup_cmd_packing). The @packed_buf is + * contiguous however, so @packed_size includes any unused + * bytes. + * - .addr: The base SPI address at which the buffer must be written to the + * switch's memory. When looking at the hardware manual, this must + * always match the lowest documented address for the ENTRY, and not + * that of the COMMAND, since the other 32-bit words will follow along + * at the correct addresses. + */ + #define SJA1105_SIZE_DYN_CMD 4 #define SJA1105ET_SIZE_MAC_CONFIG_DYN_ENTRY \ |