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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
commitace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch)
treeb2d64bc10158fdd5497876388cd68142ca374ed3 /drivers/soc/litex
parentInitial commit. (diff)
downloadlinux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz
linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/soc/litex')
-rw-r--r--drivers/soc/litex/Kconfig20
-rw-r--r--drivers/soc/litex/Makefile3
-rw-r--r--drivers/soc/litex/litex_soc_ctrl.c143
3 files changed, 166 insertions, 0 deletions
diff --git a/drivers/soc/litex/Kconfig b/drivers/soc/litex/Kconfig
new file mode 100644
index 0000000000..e6ba3573a7
--- /dev/null
+++ b/drivers/soc/litex/Kconfig
@@ -0,0 +1,20 @@
+# SPDX-License_Identifier: GPL-2.0
+
+menu "Enable LiteX SoC Builder specific drivers"
+
+config LITEX
+ bool
+
+config LITEX_SOC_CONTROLLER
+ tristate "Enable LiteX SoC Controller driver"
+ depends on OF || COMPILE_TEST
+ depends on HAS_IOMEM
+ select LITEX
+ help
+ This option enables the SoC Controller Driver which verifies
+ LiteX CSR access and provides common litex_[read|write]*
+ accessors.
+ All drivers that use functions from litex.h must depend on
+ LITEX.
+
+endmenu
diff --git a/drivers/soc/litex/Makefile b/drivers/soc/litex/Makefile
new file mode 100644
index 0000000000..98ff7325b1
--- /dev/null
+++ b/drivers/soc/litex/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License_Identifier: GPL-2.0
+
+obj-$(CONFIG_LITEX_SOC_CONTROLLER) += litex_soc_ctrl.o
diff --git a/drivers/soc/litex/litex_soc_ctrl.c b/drivers/soc/litex/litex_soc_ctrl.c
new file mode 100644
index 0000000000..f75790091d
--- /dev/null
+++ b/drivers/soc/litex/litex_soc_ctrl.c
@@ -0,0 +1,143 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * LiteX SoC Controller Driver
+ *
+ * Copyright (C) 2020 Antmicro <www.antmicro.com>
+ *
+ */
+
+#include <linux/litex.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/printk.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/reboot.h>
+
+/* reset register located at the base address */
+#define RESET_REG_OFF 0x00
+#define RESET_REG_VALUE 0x00000001
+
+#define SCRATCH_REG_OFF 0x04
+#define SCRATCH_REG_VALUE 0x12345678
+#define SCRATCH_TEST_VALUE 0xdeadbeef
+
+/*
+ * Check LiteX CSR read/write access
+ *
+ * This function reads and writes a scratch register in order to verify if CSR
+ * access works.
+ *
+ * In case any problems are detected, the driver should panic.
+ *
+ * Access to the LiteX CSR is, by design, done in CPU native endianness.
+ * The driver should not dynamically configure access functions when
+ * the endianness mismatch is detected. Such situation indicates problems in
+ * the soft SoC design and should be solved at the LiteX generator level,
+ * not in the software.
+ */
+static int litex_check_csr_access(void __iomem *reg_addr)
+{
+ unsigned long reg;
+
+ reg = litex_read32(reg_addr + SCRATCH_REG_OFF);
+
+ if (reg != SCRATCH_REG_VALUE) {
+ panic("Scratch register read error - the system is probably broken! Expected: 0x%x but got: 0x%lx",
+ SCRATCH_REG_VALUE, reg);
+ return -EINVAL;
+ }
+
+ litex_write32(reg_addr + SCRATCH_REG_OFF, SCRATCH_TEST_VALUE);
+ reg = litex_read32(reg_addr + SCRATCH_REG_OFF);
+
+ if (reg != SCRATCH_TEST_VALUE) {
+ panic("Scratch register write error - the system is probably broken! Expected: 0x%x but got: 0x%lx",
+ SCRATCH_TEST_VALUE, reg);
+ return -EINVAL;
+ }
+
+ /* restore original value of the SCRATCH register */
+ litex_write32(reg_addr + SCRATCH_REG_OFF, SCRATCH_REG_VALUE);
+
+ pr_info("LiteX SoC Controller driver initialized");
+
+ return 0;
+}
+
+struct litex_soc_ctrl_device {
+ void __iomem *base;
+ struct notifier_block reset_nb;
+};
+
+static int litex_reset_handler(struct notifier_block *this, unsigned long mode,
+ void *cmd)
+{
+ struct litex_soc_ctrl_device *soc_ctrl_dev =
+ container_of(this, struct litex_soc_ctrl_device, reset_nb);
+
+ litex_write32(soc_ctrl_dev->base + RESET_REG_OFF, RESET_REG_VALUE);
+ return NOTIFY_DONE;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id litex_soc_ctrl_of_match[] = {
+ {.compatible = "litex,soc-controller"},
+ {},
+};
+MODULE_DEVICE_TABLE(of, litex_soc_ctrl_of_match);
+#endif /* CONFIG_OF */
+
+static int litex_soc_ctrl_probe(struct platform_device *pdev)
+{
+ struct litex_soc_ctrl_device *soc_ctrl_dev;
+ int error;
+
+ soc_ctrl_dev = devm_kzalloc(&pdev->dev, sizeof(*soc_ctrl_dev), GFP_KERNEL);
+ if (!soc_ctrl_dev)
+ return -ENOMEM;
+
+ soc_ctrl_dev->base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(soc_ctrl_dev->base))
+ return PTR_ERR(soc_ctrl_dev->base);
+
+ error = litex_check_csr_access(soc_ctrl_dev->base);
+ if (error)
+ return error;
+
+ platform_set_drvdata(pdev, soc_ctrl_dev);
+
+ soc_ctrl_dev->reset_nb.notifier_call = litex_reset_handler;
+ soc_ctrl_dev->reset_nb.priority = 128;
+ error = register_restart_handler(&soc_ctrl_dev->reset_nb);
+ if (error) {
+ dev_warn(&pdev->dev, "cannot register restart handler: %d\n",
+ error);
+ }
+
+ return 0;
+}
+
+static int litex_soc_ctrl_remove(struct platform_device *pdev)
+{
+ struct litex_soc_ctrl_device *soc_ctrl_dev = platform_get_drvdata(pdev);
+
+ unregister_restart_handler(&soc_ctrl_dev->reset_nb);
+ return 0;
+}
+
+static struct platform_driver litex_soc_ctrl_driver = {
+ .driver = {
+ .name = "litex-soc-controller",
+ .of_match_table = of_match_ptr(litex_soc_ctrl_of_match)
+ },
+ .probe = litex_soc_ctrl_probe,
+ .remove = litex_soc_ctrl_remove,
+};
+
+module_platform_driver(litex_soc_ctrl_driver);
+MODULE_DESCRIPTION("LiteX SoC Controller driver");
+MODULE_AUTHOR("Antmicro <www.antmicro.com>");
+MODULE_LICENSE("GPL v2");