Add a low level driver for Altera Freeze Bridges to the FPGA Bridge framework. A freeze bridge is a bridge that exists in the FPGA fabric to isolate one region of the FPGA from the busses while that one region is being reprogrammed. Signed-off-by: Alan Tull <atull@xxxxxxxxxxxxxxxxxxxxx> Signed-off-by: Matthew Gerlach <mgerlach@xxxxxxxxxxxxxxxxxxxxx> --- v19: added in v19 of patchset as it needs for fpga info struct v20: No change for this patch in v20 of patchset --- drivers/fpga/Kconfig | 9 ++ drivers/fpga/Makefile | 1 + drivers/fpga/altera-freeze-bridge.c | 273 ++++++++++++++++++++++++++++++++++++ 3 files changed, 283 insertions(+) create mode 100644 drivers/fpga/altera-freeze-bridge.c diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig index 5605ad6..8fe6a84 100644 --- a/drivers/fpga/Kconfig +++ b/drivers/fpga/Kconfig @@ -47,6 +47,15 @@ config SOCFPGA_FPGA_BRIDGE Say Y to enable drivers for FPGA bridges for Altera SOCFPGA devices. +config ALTERA_FREEZE_BRIDGE + tristate "Altera FPGA Freeze Bridge" + depends on ARCH_SOCFPGA && FPGA_BRIDGE + help + Say Y to enable drivers for Altera FPGA Freeze bridges. A + freeze bridge is a bridge that exists in the FPGA fabric to + isolate one region of the FPGA from the busses while that + region is being reprogrammed. + endif # FPGA endmenu diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile index e658436..a6f874d 100644 --- a/drivers/fpga/Makefile +++ b/drivers/fpga/Makefile @@ -12,6 +12,7 @@ obj-$(CONFIG_FPGA_MGR_ZYNQ_FPGA) += zynq-fpga.o # FPGA Bridge Drivers obj-$(CONFIG_FPGA_BRIDGE) += fpga-bridge.o obj-$(CONFIG_SOCFPGA_FPGA_BRIDGE) += altera-hps2fpga.o altera-fpga2sdram.o +obj-$(CONFIG_ALTERA_FREEZE_BRIDGE) += altera-freeze-bridge.o # High Level Interfaces obj-$(CONFIG_FPGA_REGION) += fpga-region.o diff --git a/drivers/fpga/altera-freeze-bridge.c b/drivers/fpga/altera-freeze-bridge.c new file mode 100644 index 0000000..8dcd9fb --- /dev/null +++ b/drivers/fpga/altera-freeze-bridge.c @@ -0,0 +1,273 @@ +/* + * FPGA Freeze Bridge Controller + * + * Copyright (C) 2016 Altera Corporation. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program. If not, see <http://www.gnu.org/licenses/>. + */ +#include <linux/delay.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/of_device.h> +#include <linux/module.h> +#include <linux/fpga/fpga-bridge.h> + +#define FREEZE_CSR_STATUS_OFFSET 0 +#define FREEZE_CSR_CTRL_OFFSET 4 +#define FREEZE_CSR_ILLEGAL_REQ_OFFSET 8 +#define FREEZE_CSR_REG_VERSION 12 + +#define FREEZE_CSR_SUPPORTED_VERSION 2 + +#define FREEZE_CSR_STATUS_FREEZE_REQ_DONE BIT(0) +#define FREEZE_CSR_STATUS_UNFREEZE_REQ_DONE BIT(1) + +#define FREEZE_CSR_CTRL_FREEZE_REQ BIT(0) +#define FREEZE_CSR_CTRL_RESET_REQ BIT(1) +#define FREEZE_CSR_CTRL_UNFREEZE_REQ BIT(2) + +#define FREEZE_BRIDGE_NAME "freeze" + +struct altera_freeze_br_data { + struct device *dev; + void __iomem *base_addr; + bool enable; +}; + +/* + * Poll status until status bit is set or we have a timeout. + */ +static int altera_freeze_br_req_ack(struct altera_freeze_br_data *priv, + u32 timeout, u32 req_ack) +{ + struct device *dev = priv->dev; + void __iomem *csr_illegal_req_addr = priv->base_addr + + FREEZE_CSR_ILLEGAL_REQ_OFFSET; + u32 status, illegal, ctrl; + int ret = -ETIMEDOUT; + + do { + illegal = readl(csr_illegal_req_addr); + if (illegal) { + dev_err(dev, "illegal request detected 0x%x", illegal); + + writel(1, csr_illegal_req_addr); + + illegal = readl(csr_illegal_req_addr); + if (illegal) + dev_err(dev, "illegal request not cleared 0x%x", + illegal); + + ret = -EINVAL; + break; + } + + status = readl(priv->base_addr + FREEZE_CSR_STATUS_OFFSET); + dev_dbg(dev, "%s %x %x\n", __func__, status, req_ack); + status &= req_ack; + if (status) { + ctrl = readl(priv->base_addr + FREEZE_CSR_CTRL_OFFSET); + dev_dbg(dev, "%s request %x acknowledged %x %x\n", + __func__, req_ack, status, ctrl); + ret = 0; + break; + } + + udelay(1); + } while (timeout--); + + if (ret == -ETIMEDOUT) + dev_err(dev, "%s timeout waiting for 0x%x\n", + __func__, req_ack); + + return ret; +} + +static int altera_freeze_br_do_freeze(struct altera_freeze_br_data *priv, + u32 timeout) +{ + struct device *dev = priv->dev; + void __iomem *csr_ctrl_addr = priv->base_addr + + FREEZE_CSR_CTRL_OFFSET; + u32 status; + int ret; + + status = readl(priv->base_addr + FREEZE_CSR_STATUS_OFFSET); + + dev_dbg(dev, "%s %d %d\n", __func__, status, readl(csr_ctrl_addr)); + + if (status & FREEZE_CSR_STATUS_FREEZE_REQ_DONE) { + dev_dbg(dev, "%s bridge already disabled %d\n", + __func__, status); + return 0; + } else if (!(status & FREEZE_CSR_STATUS_UNFREEZE_REQ_DONE)) { + dev_err(dev, "%s bridge not enabled %d\n", __func__, status); + return -EINVAL; + } + + writel(FREEZE_CSR_CTRL_FREEZE_REQ, csr_ctrl_addr); + + ret = altera_freeze_br_req_ack(priv, timeout, + FREEZE_CSR_STATUS_FREEZE_REQ_DONE); + + if (ret) + writel(0, csr_ctrl_addr); + else + writel(FREEZE_CSR_CTRL_RESET_REQ, csr_ctrl_addr); + + return ret; +} + +static int altera_freeze_br_do_unfreeze(struct altera_freeze_br_data *priv, + u32 timeout) +{ + struct device *dev = priv->dev; + void __iomem *csr_ctrl_addr = priv->base_addr + + FREEZE_CSR_CTRL_OFFSET; + u32 status; + int ret; + + writel(0, csr_ctrl_addr); + + status = readl(priv->base_addr + FREEZE_CSR_STATUS_OFFSET); + + dev_dbg(dev, "%s %d %d\n", __func__, status, readl(csr_ctrl_addr)); + + if (status & FREEZE_CSR_STATUS_UNFREEZE_REQ_DONE) { + dev_dbg(dev, "%s bridge already enabled %d\n", + __func__, status); + return 0; + } else if (!(status & FREEZE_CSR_STATUS_FREEZE_REQ_DONE)) { + dev_err(dev, "%s bridge not frozen %d\n", __func__, status); + return -EINVAL; + } + + writel(FREEZE_CSR_CTRL_UNFREEZE_REQ, csr_ctrl_addr); + + ret = altera_freeze_br_req_ack(priv, timeout, + FREEZE_CSR_STATUS_UNFREEZE_REQ_DONE); + + status = readl(priv->base_addr + FREEZE_CSR_STATUS_OFFSET); + + dev_dbg(dev, "%s %d %d\n", __func__, status, readl(csr_ctrl_addr)); + + writel(0, csr_ctrl_addr); + + return ret; +} + +/* + * enable = 1 : allow traffic through the bridge + * enable = 0 : disable traffic through the bridge + */ +static int altera_freeze_br_enable_set(struct fpga_bridge *bridge, + bool enable) +{ + struct altera_freeze_br_data *priv = bridge->priv; + struct fpga_image_info *info = bridge->info; + u32 timeout = 0; + int ret; + + if (enable) { + if (info) + timeout = info->enable_timeout_us; + + ret = altera_freeze_br_do_unfreeze(bridge->priv, timeout); + } else { + if (info) + timeout = info->disable_timeout_us; + + ret = altera_freeze_br_do_freeze(bridge->priv, timeout); + } + + if (!ret) + priv->enable = enable; + + return ret; +} + +static int altera_freeze_br_enable_show(struct fpga_bridge *bridge) +{ + struct altera_freeze_br_data *priv = bridge->priv; + + return priv->enable; +} + +static struct fpga_bridge_ops altera_freeze_br_br_ops = { + .enable_set = altera_freeze_br_enable_set, + .enable_show = altera_freeze_br_enable_show, +}; + +static const struct of_device_id altera_freeze_br_of_match[] = { + { .compatible = "altr,freeze-bridge-controller", }, + {}, +}; +MODULE_DEVICE_TABLE(of, altera_freeze_br_of_match); + +static int altera_freeze_br_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct device_node *np = pdev->dev.of_node; + struct altera_freeze_br_data *priv; + struct resource *res; + u32 status, revision; + + if (!np) + return -ENODEV; + + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->dev = dev; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + priv->base_addr = devm_ioremap_resource(dev, res); + if (IS_ERR(priv->base_addr)) + return PTR_ERR(priv->base_addr); + + status = readl(priv->base_addr + FREEZE_CSR_STATUS_OFFSET); + if (status & FREEZE_CSR_STATUS_UNFREEZE_REQ_DONE) + priv->enable = 1; + + revision = readl(priv->base_addr + FREEZE_CSR_REG_VERSION); + if (revision != FREEZE_CSR_SUPPORTED_VERSION) + dev_warn(dev, + "%s Freeze Controller unexpected revision %d != %d\n", + __func__, revision, FREEZE_CSR_SUPPORTED_VERSION); + + return fpga_bridge_register(dev, FREEZE_BRIDGE_NAME, + &altera_freeze_br_br_ops, priv); +} + +static int altera_freeze_br_remove(struct platform_device *pdev) +{ + fpga_bridge_unregister(&pdev->dev); + + return 0; +} + +static struct platform_driver altera_freeze_br_driver = { + .probe = altera_freeze_br_probe, + .remove = altera_freeze_br_remove, + .driver = { + .name = "altera_freeze_br", + .of_match_table = of_match_ptr(altera_freeze_br_of_match), + }, +}; + +module_platform_driver(altera_freeze_br_driver); + +MODULE_DESCRIPTION("Altera Freeze Bridge"); +MODULE_AUTHOR("Alan Tull <atull@xxxxxxxxxxxxxxxxxxxxx>"); +MODULE_LICENSE("GPL v2"); -- 2.10.1 -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
