linux/drivers/fpga/altera-freeze-bridge.c
Uwe Kleine-König 15732fa43b
fpga: altera-freeze-bridge: Convert to platform remove callback returning void
The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.

To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new(), which already returns void. Eventually after all drivers
are converted, .remove_new() will be renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Xu Yilun <yilun.xu@intel.com>
Link: https://lore.kernel.org/r/7f4fcb23b25400c6711848105823081e032c5266.1703006638.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Xu Yilun <yilun.xu@linux.intel.com>
2023-12-21 22:31:40 +08:00

277 lines
6.7 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* FPGA Freeze Bridge Controller
*
* Copyright (C) 2016 Altera Corporation. All rights reserved.
*/
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_device.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_OFFICIAL_VERSION 0xad000003
#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 const 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;
void __iomem *base_addr;
struct altera_freeze_br_data *priv;
struct fpga_bridge *br;
u32 status, revision;
if (!np)
return -ENODEV;
base_addr = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(base_addr))
return PTR_ERR(base_addr);
revision = readl(base_addr + FREEZE_CSR_REG_VERSION);
if ((revision != FREEZE_CSR_SUPPORTED_VERSION) &&
(revision != FREEZE_CSR_OFFICIAL_VERSION)) {
dev_err(dev,
"%s unexpected revision 0x%x != 0x%x != 0x%x\n",
__func__, revision, FREEZE_CSR_SUPPORTED_VERSION,
FREEZE_CSR_OFFICIAL_VERSION);
return -EINVAL;
}
priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
priv->dev = dev;
status = readl(base_addr + FREEZE_CSR_STATUS_OFFSET);
if (status & FREEZE_CSR_STATUS_UNFREEZE_REQ_DONE)
priv->enable = 1;
priv->base_addr = base_addr;
br = fpga_bridge_register(dev, FREEZE_BRIDGE_NAME,
&altera_freeze_br_br_ops, priv);
if (IS_ERR(br))
return PTR_ERR(br);
platform_set_drvdata(pdev, br);
return 0;
}
static void altera_freeze_br_remove(struct platform_device *pdev)
{
struct fpga_bridge *br = platform_get_drvdata(pdev);
fpga_bridge_unregister(br);
}
static struct platform_driver altera_freeze_br_driver = {
.probe = altera_freeze_br_probe,
.remove_new = altera_freeze_br_remove,
.driver = {
.name = "altera_freeze_br",
.of_match_table = altera_freeze_br_of_match,
},
};
module_platform_driver(altera_freeze_br_driver);
MODULE_DESCRIPTION("Altera Freeze Bridge");
MODULE_AUTHOR("Alan Tull <atull@opensource.altera.com>");
MODULE_LICENSE("GPL v2");