ARM: socfpga: Add driver for the L3 interconnect

The L3 interconnect provides Global Programmer View (GPV) registers for every AXI master and slave on the SoC.
Although this is just a bunch of bits, syscon is not the right approach for this IP core.
The L3 interconnect is configured with a lot of reserved "holes" in its memory space. Just mapping this with regmap, what syscon would do, would lead to the system completely hanging, if one of those areas would be touched. One example for when this might happen is the regmap registers dump in the debugfs.

This driver specifies also the valid readable and writable ranges of the L3 interconnect. Other drivers that want to access their GPV registers can do so with this driver via socfpga_l3nic_regmap_by_phandle.

Signed-off-by Steffen Trumtrar <[email protected]>

---
 .../bindings/soc/socfpga/altr,l3-nic.txt           |  15 ++
 drivers/soc/Kconfig                                |   1 +
 drivers/soc/Makefile                               |   1 +
 drivers/soc/socfpga/Kconfig                        |  11 +
 drivers/soc/socfpga/Makefile                       |   1 +
 drivers/soc/socfpga/l3nic.c                        | 221 +++++++++++++++++++++
 include/soc/socfpga/gpv.h                          |  63 ++++++
 include/soc/socfpga/l3regs.h                       | 194 ++++++++++++++++++
 8 files changed, 507 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/soc/socfpga/altr,l3-nic.txt
 create mode 100644 drivers/soc/socfpga/Kconfig
 create mode 100644 drivers/soc/socfpga/Makefile
 create mode 100644 drivers/soc/socfpga/l3nic.c
 create mode 100644 include/soc/socfpga/gpv.h
 create mode 100644 include/soc/socfpga/l3regs.h

Quoted 15 lines · Steffen Trumtrar

The L3 interconnect provides Global Programmer View (GPV) registers for every AXI master and slave on the SoC.
Although this is just a bunch of bits, syscon is not the right approach for this IP core.
The L3 interconnect is configured with a lot of reserved "holes" in its memory space. Just mapping this with regmap, what syscon would do, would lead to the system completely hanging, if one of those areas would be touched. One example for when this might happen is the regmap registers dump in the debugfs.

This driver specifies also the valid readable and writable ranges of the L3 interconnect. Other drivers that want to access their GPV registers can do so with this driver via socfpga_l3nic_regmap_by_phandle.

Signed-off-by Steffen Trumtrar <[email protected]>

Quoted 17 lines

---
 .../bindings/soc/socfpga/altr,l3-nic.txt           |  15 ++
 drivers/soc/Kconfig                                |   1 +
 drivers/soc/Makefile                               |   1 +
 drivers/soc/socfpga/Kconfig                        |  11 +
 drivers/soc/socfpga/Makefile                       |   1 +
 drivers/soc/socfpga/l3nic.c                        | 221 +++++++++++++++++++++
 include/soc/socfpga/gpv.h                          |  63 ++++++
 include/soc/socfpga/l3regs.h                       | 194 ++++++++++++++++++
 8 files changed, 507 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/soc/socfpga/altr,l3-nic.txt
 create mode 100644 drivers/soc/socfpga/Kconfig
 create mode 100644 drivers/soc/socfpga/Makefile
 create mode 100644 drivers/soc/socfpga/l3nic.c
 create mode 100644 include/soc/socfpga/gpv.h
 create mode 100644 include/soc/socfpga/l3regs.h

Hi Steffen,

This looks really nice and useful.

I tried it out with my bridge driver and at least with my superficial testing it looked good.

drivers/soc/socfpga/l3nic.c line 151

Quoted 5 lines

drivers/soc/socfpga/l3nic.c new file +5 -0

+
+int socfpga_l3nic_regmap_by_phandle(struct device_node *np,
+				    struct regmap **regmap,
+				    const char *name)
+{

This could return the regmap or ERR_PTR(-ENODEV) and just have the np and name parameter, similar to syscon_regmap_lookup_by_phandle.

Quoted 10 lines

drivers/soc/socfpga/l3nic.c line 151

Quoted 5 lines

drivers/soc/socfpga/l3nic.c new file +5 -0

+
+int socfpga_l3nic_regmap_by_phandle(struct device_node *np,
+				    struct regmap **regmap,
+				    const char *name)
+{

This could return the regmap or ERR_PTR(-ENODEV) and just have the np and name parameter, similar to syscon_regmap_lookup_by_phandle.

I wanted to do that, but I also want to propagate the return value of socfpga_gpv_device_by_phandle and this doesn't seem to work than. Open for suggestions, though.