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// SPDX-License-Identifier: GPL-2.0-only
/*
* Xilinx Spartan6 and 7 Series SelectMAP interface driver
*
* (C) 2024 Charles Perry <charles.perry@savoirfairelinux.com>
*
* Manage Xilinx FPGA firmware loaded over the SelectMAP configuration
* interface.
*/
#include "xilinx-core.h"
#include <linux/gpio/consumer.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
struct xilinx_selectmap_conf {
struct xilinx_fpga_core core;
void __iomem *base;
struct gpio_desc *csi_b;
struct gpio_desc *rdwr_b;
};
#define to_xilinx_selectmap_conf(obj) \
container_of(obj, struct xilinx_selectmap_conf, core)
static int xilinx_selectmap_write(struct xilinx_fpga_core *core,
const char *buf, size_t count)
{
struct xilinx_selectmap_conf *conf = to_xilinx_selectmap_conf(core);
size_t i;
/*
* Select this device and put its SelectMAP port into write mode.
*
* RDWR_B is set before CSI_B. UG470 describes in chapter
* "SelectMAP ABORT" that changing RDWR_B while the device is
* selected aborts the configuration on the next CCLK.
*/
gpiod_set_value(conf->rdwr_b, 1);
gpiod_set_value(conf->csi_b, 1);
for (i = 0; i < count; ++i)
writeb(buf[i], conf->base);
gpiod_set_value(conf->csi_b, 0);
gpiod_set_value(conf->rdwr_b, 0);
return 0;
}
static int xilinx_selectmap_probe(struct platform_device *pdev)
{
struct xilinx_selectmap_conf *conf;
void __iomem *base;
conf = devm_kzalloc(&pdev->dev, sizeof(*conf), GFP_KERNEL);
if (!conf)
return -ENOMEM;
conf->core.dev = &pdev->dev;
conf->core.write = xilinx_selectmap_write;
base = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
if (IS_ERR(base))
return dev_err_probe(&pdev->dev, PTR_ERR(base),
"ioremap error\n");
conf->base = base;
/*
* Request both signals deasserted, so a device sharing the SelectMAP
* bus with others stays off that bus until its bitstream is written.
*
* The value in the gpiod flags is logical, gpiolib drives the line
* high for GPIOD_OUT_LOW when the firmware describes it active low.
*/
conf->csi_b = devm_gpiod_get_optional(&pdev->dev, "csi",
GPIOD_OUT_LOW);
if (IS_ERR(conf->csi_b))
return dev_err_probe(&pdev->dev, PTR_ERR(conf->csi_b),
"Failed to get CSI_B gpio\n");
conf->rdwr_b = devm_gpiod_get_optional(&pdev->dev, "rdwr",
GPIOD_OUT_LOW);
if (IS_ERR(conf->rdwr_b))
return dev_err_probe(&pdev->dev, PTR_ERR(conf->rdwr_b),
"Failed to get RDWR_B gpio\n");
return xilinx_core_probe(&conf->core);
}
static const struct of_device_id xlnx_selectmap_of_match[] = {
{ .compatible = "xlnx,fpga-xc7s-selectmap", }, // Spartan-7
{ .compatible = "xlnx,fpga-xc7a-selectmap", }, // Artix-7
{ .compatible = "xlnx,fpga-xc7k-selectmap", }, // Kintex-7
{ .compatible = "xlnx,fpga-xc7v-selectmap", }, // Virtex-7
{},
};
MODULE_DEVICE_TABLE(of, xlnx_selectmap_of_match);
static struct platform_driver xilinx_selectmap_driver = {
.driver = {
.name = "xilinx-selectmap",
.of_match_table = xlnx_selectmap_of_match,
},
.probe = xilinx_selectmap_probe,
};
module_platform_driver(xilinx_selectmap_driver);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Charles Perry <charles.perry@savoirfairelinux.com>");
MODULE_DESCRIPTION("Load Xilinx FPGA firmware over SelectMap");
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