On Mon, 24 Oct 2016, Joel Holdsworth wrote: > The Lattice iCE40 is a family of FPGAs with a minimalistic architecture > and very regular structure, designed for low-cost, high-volume consumer > and system applications. > > This patch adds support to the FPGA manager for configuring the SRAM of > iCE40LM, iCE40LP, iCE40HX, iCE40 Ultra, iCE40 UltraLite and iCE40 > UltraPlus devices, through slave SPI. > > The iCE40 family is notable because it is the first FPGA family to have > complete reverse engineered bit-stream documentation for the iCE40LP and > iCE40HX devices. Furthermore, there is now a Free Software Verilog > synthesis tool-chain: the "IceStorm" tool-chain. > > This project is the work of Clifford Wolf, who is the maintainer of > Yosys Verilog RTL synthesis framework, and Mathias Lasser, with notable > contributions from "Cotton Seed", the main author of "arachne-pnr"; a > place-and-route tool for iCE40 FPGAs. > > Having a Free Software synthesis tool-chain offers interesting > opportunities for embedded devices that are able reconfigure themselves > with open firmware that is generated on the device itself. For example > a mobile device might have an application processer with an iCE40 FPGA > attached, which implements slave devices, or through which the processor > communicates with other devices through the FPGA fabric. > > A kernel driver for the iCE40 is useful, because in some cases, the FPGA > may need to be configured before other devices can be accessed. > > An example of such a device is the icoBOARD; a RaspberryPI HAT which > features an iCE40HX8K with a 1 or 8 MBit SRAM and ports for > Digilent-compatible PMOD modules. A PMOD module may contain a device > with which the kernel communicates, via the FPGA. > --- > .../bindings/fpga/lattice-ice40-fpga-mgr.txt | 23 +++ > drivers/fpga/Kconfig | 6 + > drivers/fpga/Makefile | 1 + > drivers/fpga/ice40spi.c | 212 +++++++++++++++++++++ > 4 files changed, 242 insertions(+) > create mode 100644 Documentation/devicetree/bindings/fpga/lattice-ice40-fpga-mgr.txt > create mode 100644 drivers/fpga/ice40spi.c > Hi Joel, Thanks for submitting your driver! I didn't see any huge problems, just minor things below... Alan > diff --git a/Documentation/devicetree/bindings/fpga/lattice-ice40-fpga-mgr.txt b/Documentation/devicetree/bindings/fpga/lattice-ice40-fpga-mgr.txt > new file mode 100644 > index 0000000..b253ac8 > --- /dev/null > +++ b/Documentation/devicetree/bindings/fpga/lattice-ice40-fpga-mgr.txt > @@ -0,0 +1,23 @@ > +Lattice iCE40 FPGA Manager > + > +Required properties: > +- compatible: should contain "lattice,ice40-fpga-mgr" > +- reg: SPI chip select > +- spi-max-frequency: Maximum SPI frequency (>=1000000, <=25000000) > +- cdone-gpios: GPIO connected to CDONE pin > +- creset_b-gpios: GPIO connected to CRESET_B pin. Note that CRESET_B is > + treated as an active-low output because the signal is > + treated as an enable signal, rather than a reset. This > + is necessary because the FPGA will enter Master SPI > + mode and drive SCK with a clock signal, potentially > + jamming other devices on the bus, unless CRESET_B is > + held high until the firmware is loaded. Both could be singular ...-gpio since only one gpio should be specified. > + > +Example: > + ice40: ice40@0 { > + compatible = "lattice,ice40-fpga-mgr"; > + reg = <0>; > + spi-max-frequency = <1000000>; > + cdone-gpios = <&gpio 24 GPIO_ACTIVE_HIGH>; > + creset_b-gpios = <&gpio 22 GPIO_ACTIVE_LOW>; > + }; > diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig > index d614102..85ff429 100644 > --- a/drivers/fpga/Kconfig > +++ b/drivers/fpga/Kconfig > @@ -13,6 +13,12 @@ config FPGA > > if FPGA > > +config FPGA_MGR_ICE40_SPI > + tristate "Lattice iCE40 SPI" > + depends on SPI > + help > + FPGA manager driver support for Lattice iCE40 FPGAs over SPI. > + > config FPGA_MGR_SOCFPGA > tristate "Altera SOCFPGA FPGA Manager" > depends on ARCH_SOCFPGA > diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile > index 8d83fc6..6c809cc 100644 > --- a/drivers/fpga/Makefile > +++ b/drivers/fpga/Makefile > @@ -6,5 +6,6 @@ > obj-$(CONFIG_FPGA) += fpga-mgr.o > > # FPGA Manager Drivers > +obj-$(CONFIG_FPGA_MGR_ICE40_SPI) += ice40spi.o Could this be ice40-spi.c? > obj-$(CONFIG_FPGA_MGR_SOCFPGA) += socfpga.o > obj-$(CONFIG_FPGA_MGR_ZYNQ_FPGA) += zynq-fpga.o > diff --git a/drivers/fpga/ice40spi.c b/drivers/fpga/ice40spi.c > new file mode 100644 > index 0000000..ab5ee86 > --- /dev/null > +++ b/drivers/fpga/ice40spi.c > @@ -0,0 +1,212 @@ > +/* > + * FPGA Manager Driver for Lattice iCE40. > + * > + * Copyright (c) 2016 Joel Holdsworth > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License as published by > + * the Free Software Foundation; version 2 of the License. > + * > + * This driver adds support to the FPGA manager for configuring the SRAM of > + * Lattice iCE40 FPGAs through slave SPI. > + */ > + > +#include <linux/delay.h> > +#include <linux/fpga/fpga-mgr.h> > +#include <linux/gpio/consumer.h> > +#include <linux/of_gpio.h> > +#include <linux/spi/spi.h> > + > +struct ice40_fpga_priv { > + struct spi_device *dev; > + struct gpio_desc *creset_b; > + struct gpio_desc *cdone; > + enum fpga_mgr_states state; state is never used. You could just remove it. > +}; > + > +static enum fpga_mgr_states ice40_fpga_ops_state(struct fpga_manager *mgr) > +{ > + return mgr->state; fpga_mgr_register will call your ice40_fpga_ops_state() function to get its initial state. That's the only time this gets called. So you could return one of the enum fpga_mgr_states here. I'm guessing FPGA_MGR_STATE_UNKNOWN. I'm realizing that there will be devices that don't really know what initial state they are in; I could have removed the absolute requirement for the state in the fpga_manager_ops and assumed FPGA_MGR_STATE_UNKNOWN unless a low level driver provided a state function. But for now, just return FPGA_MGR_STATE_UNKNOWN here unless you have a way of knowing what state you are in when the driver is probed. > +} > + > +static void set_cs(struct spi_device *spi, bool enable) > +{ > + if (gpio_is_valid(spi->cs_gpio)) > + gpio_set_value(spi->cs_gpio, !enable); > + else if (spi->master->set_cs) > + spi->master->set_cs(spi, !enable); > +} > + > +static int ice40_fpga_ops_write_init(struct fpga_manager *mgr, u32 flags, > + const char *buf, size_t count) Checkpatch complains about alignment here. > +{ > + struct ice40_fpga_priv *priv = mgr->priv; > + struct spi_device *dev = priv->dev; > + int ret; > + > + if ((flags & FPGA_MGR_PARTIAL_RECONFIG)) { > + dev_err(&dev->dev, > + "Partial reconfiguration is not supported\n"); > + return -EINVAL; > + } > + > + /* Lock the bus, assert SS_B and CRESET_B */ > + ret = spi_bus_lock(dev->master); > + if (ret) { > + dev_err(&dev->dev, "Failed to lock SPI bus, ret: %d\n", ret); > + return ret; > + } > + > + set_cs(dev, 1); > + gpiod_set_value(priv->creset_b, 1); > + > + /* Delay for >200ns */ > + udelay(1); > + > + /* Come out of reset */ > + gpiod_set_value(priv->creset_b, 0); > + > + /* Check CDONE is de-asserted i.e. the FPGA is reset */ > + if (gpiod_get_value(priv->cdone)) { > + dev_err(&dev->dev, "Device reset failed, CDONE is asserted\n"); > + ret = -EIO; > + } > + > + /* Wait for the housekeeping to complete */ > + if (!ret) > + udelay(1200); Would usleep_range work for you since it's more than 10uSec (Documentation/timers/timers-howto.txt)? > + > + /* Release the SS_B */ > + set_cs(dev, 0); > + spi_bus_unlock(dev->master); > + > + return ret; > +} > + > +static int ice40_fpga_ops_write(struct fpga_manager *mgr, > + const char *buf, size_t count) Checkpatch complains about alignment here also. > +{ > + struct ice40_fpga_priv *priv = mgr->priv; > + struct spi_device *dev = priv->dev; > + int ret; > + > + ret = spi_write(dev, buf, count); > + if (ret) > + dev_err(&dev->dev, "Error sending SPI data, ret: %d\n", ret); > + > + return ret; > +} > + > +static int ice40_fpga_ops_write_complete(struct fpga_manager *mgr, u32 flags) > +{ > + struct ice40_fpga_priv *priv = mgr->priv; > + struct spi_device *dev = priv->dev; > + int ret = 0; > + > + /* Check CDONE is asserted */ > + if (!gpiod_get_value(priv->cdone)) { > + dev_err(&dev->dev, > + "CDONE was not asserted after firmware transfer\n"); > + return -EIO; > + } > + > + /* Send >49-bits of zero-padding to activate the firmware */ > + ret = spi_write(dev, NULL, 7); > + if (ret) { > + dev_err(&dev->dev, "Error sending zero padding, ret: %d\n", > + ret); > + return ret; > + } > + > + /* Success */ > + return 0; > +} > + > +static const struct fpga_manager_ops ice40_fpga_ops = { > + .state = ice40_fpga_ops_state, > + .write_init = ice40_fpga_ops_write_init, > + .write = ice40_fpga_ops_write, > + .write_complete = ice40_fpga_ops_write_complete, > +}; > + > +static int ice40_fpga_probe(struct spi_device *spi) > +{ > + struct device *dev = &spi->dev; > + struct device_node *np = spi->dev.of_node; > + struct ice40_fpga_priv *priv; > + int ret; > + > + if (!np) { > + dev_err(dev, "No Device Tree entry\n"); > + return -EINVAL; > + } > + > + priv = devm_kzalloc(&spi->dev, sizeof(*priv), GFP_KERNEL); > + if (!priv) > + return -ENOMEM; > + > + priv->dev = spi; > + > + /* Check board setup data. */ > + if (spi->max_speed_hz > 25000000) { > + dev_err(dev, "speed is too high\n"); > + return -EINVAL; > + } else if (spi->mode & SPI_CPHA) { > + dev_err(dev, "bad mode\n"); > + return -EINVAL; > + } > + > + /* Set up the GPIOs */ > + priv->cdone = devm_gpiod_get(dev, "cdone", GPIOD_IN); > + if (IS_ERR(priv->cdone)) { > + dev_err(dev, "Failed to get CDONE GPIO: %ld\n", > + PTR_ERR(priv->cdone)); > + return ret; > + } > + > + priv->creset_b = devm_gpiod_get(dev, "creset_b", GPIOD_OUT_HIGH); > + if (IS_ERR(priv->creset_b)) { > + dev_err(dev, "Failed to get CRESET_B GPIO: %ld\n", > + PTR_ERR(priv->creset_b)); > + return ret; > + } > + > + /* Register with the FPGA manager */ > + ret = fpga_mgr_register(dev, "Lattice iCE40 FPGA Manager", > + &ice40_fpga_ops, priv); > + if (ret) { > + dev_err(dev, "unable to register FPGA manager"); > + return ret; > + } > + > + return 0; > +} > + > +static int ice40_fpga_remove(struct spi_device *spi) > +{ > + fpga_mgr_unregister(&spi->dev); > + return 0; > +} > + #ifdef CONFIG_OF > +static const struct of_device_id ice40_fpga_of_match[] = { > + { .compatible = "lattice,ice40-fpga-mgr", }, > + {}, > +}; > + > +MODULE_DEVICE_TABLE(of, ice40_fpga_of_match); #endif > + > +static struct spi_driver ice40_fpga_driver = { > + .probe = ice40_fpga_probe, > + .remove = ice40_fpga_remove, > + .driver = { > + .name = "ice40spi", > + .owner = THIS_MODULE, It's not necessary to specify .owner anymore. > + .of_match_table = of_match_ptr(ice40_fpga_of_match), > + }, > +}; > + > +module_spi_driver(ice40_fpga_driver); > + > +MODULE_AUTHOR("Joel Holdsworth <joel@xxxxxxxxxxxxxxxxxxx>"); > +MODULE_DESCRIPTION("Lattice iCE40 FPGA Manager"); > +MODULE_LICENSE("GPL v2"); > -- > 2.7.4 > > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html