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authorLinus Torvalds <torvalds@linux-foundation.org>2020-12-18 00:41:27 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2020-12-18 00:41:27 +0300
commit0c6c887835b59c10602add88057c9c06f265effe (patch)
treeb1ef9be8f1bc9f133803673b42b1b701ef79ecf2 /drivers/soc
parent8a5be36b9303ae167468d4f5e1b3c090b9981396 (diff)
parentd8398bf840f8964220508aff7901c924e322f5e8 (diff)
downloadlinux-0c6c887835b59c10602add88057c9c06f265effe.tar.xz
Merge tag 'for-linus' of git://github.com/openrisc/linux
Pull OpenRISC updates from Stafford Horne: - New drivers and OpenRISC support for the LiteX platform - A bug fix to support userspace gdb debugging - Fixes one compile issue with blk-iocost * tag 'for-linus' of git://github.com/openrisc/linux: openrisc: add local64.h to fix blk-iocost build openrisc: fix trap for debugger breakpoint signalling openrisc: add support for LiteX drivers/tty/serial: add LiteUART driver dt-bindings: serial: document LiteUART bindings drivers/soc/litex: add LiteX SoC Controller driver dt-bindings: soc: document LiteX SoC Controller bindings dt-bindings: vendor: add vendor prefix for LiteX
Diffstat (limited to 'drivers/soc')
-rw-r--r--drivers/soc/Kconfig1
-rw-r--r--drivers/soc/Makefile1
-rw-r--r--drivers/soc/litex/Kconfig19
-rw-r--r--drivers/soc/litex/Makefile3
-rw-r--r--drivers/soc/litex/litex_soc_ctrl.c176
5 files changed, 200 insertions, 0 deletions
diff --git a/drivers/soc/Kconfig b/drivers/soc/Kconfig
index 425ab6f7e375..d097d070f579 100644
--- a/drivers/soc/Kconfig
+++ b/drivers/soc/Kconfig
@@ -9,6 +9,7 @@ source "drivers/soc/bcm/Kconfig"
source "drivers/soc/fsl/Kconfig"
source "drivers/soc/imx/Kconfig"
source "drivers/soc/ixp4xx/Kconfig"
+source "drivers/soc/litex/Kconfig"
source "drivers/soc/mediatek/Kconfig"
source "drivers/soc/qcom/Kconfig"
source "drivers/soc/renesas/Kconfig"
diff --git a/drivers/soc/Makefile b/drivers/soc/Makefile
index 8fa43a2d17e7..699b758d28e4 100644
--- a/drivers/soc/Makefile
+++ b/drivers/soc/Makefile
@@ -14,6 +14,7 @@ obj-$(CONFIG_ARCH_GEMINI) += gemini/
obj-y += imx/
obj-$(CONFIG_ARCH_IXP4XX) += ixp4xx/
obj-$(CONFIG_SOC_XWAY) += lantiq/
+obj-$(CONFIG_LITEX_SOC_CONTROLLER) += litex/
obj-y += mediatek/
obj-y += amlogic/
obj-y += qcom/
diff --git a/drivers/soc/litex/Kconfig b/drivers/soc/litex/Kconfig
new file mode 100644
index 000000000000..7c6b009b6f6c
--- /dev/null
+++ b/drivers/soc/litex/Kconfig
@@ -0,0 +1,19 @@
+# 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
+ select LITEX
+ help
+ This option enables the SoC Controller Driver which verifies
+ LiteX CSR access and provides common litex_get_reg/litex_set_reg
+ 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 000000000000..98ff7325b1c0
--- /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 000000000000..1217cafdfd4d
--- /dev/null
+++ b/drivers/soc/litex/litex_soc_ctrl.c
@@ -0,0 +1,176 @@
+// 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/errno.h>
+#include <linux/io.h>
+
+/*
+ * LiteX SoC Generator, depending on the configuration, can split a single
+ * logical CSR (Control&Status Register) into a series of consecutive physical
+ * registers.
+ *
+ * For example, in the configuration with 8-bit CSR Bus, 32-bit aligned (the
+ * default one for 32-bit CPUs) a 32-bit logical CSR will be generated as four
+ * 32-bit physical registers, each one containing one byte of meaningful data.
+ *
+ * For details see: https://github.com/enjoy-digital/litex/wiki/CSR-Bus
+ *
+ * The purpose of `litex_set_reg`/`litex_get_reg` is to implement the logic
+ * of writing to/reading from the LiteX CSR in a single place that can be
+ * then reused by all LiteX drivers.
+ */
+
+/**
+ * litex_set_reg() - Writes the value to the LiteX CSR (Control&Status Register)
+ * @reg: Address of the CSR
+ * @reg_size: The width of the CSR expressed in the number of bytes
+ * @val: Value to be written to the CSR
+ *
+ * In the currently supported LiteX configuration (8-bit CSR Bus, 32-bit aligned),
+ * a 32-bit LiteX CSR is generated as 4 consecutive 32-bit physical registers,
+ * each one containing one byte of meaningful data.
+ *
+ * This function splits a single possibly multi-byte write into a series of
+ * single-byte writes with a proper offset.
+ */
+void litex_set_reg(void __iomem *reg, unsigned long reg_size,
+ unsigned long val)
+{
+ unsigned long shifted_data, shift, i;
+
+ for (i = 0; i < reg_size; ++i) {
+ shift = ((reg_size - i - 1) * LITEX_SUBREG_SIZE_BIT);
+ shifted_data = val >> shift;
+
+ WRITE_LITEX_SUBREGISTER(shifted_data, reg, i);
+ }
+}
+EXPORT_SYMBOL_GPL(litex_set_reg);
+
+/**
+ * litex_get_reg() - Reads the value of the LiteX CSR (Control&Status Register)
+ * @reg: Address of the CSR
+ * @reg_size: The width of the CSR expressed in the number of bytes
+ *
+ * Return: Value read from the CSR
+ *
+ * In the currently supported LiteX configuration (8-bit CSR Bus, 32-bit aligned),
+ * a 32-bit LiteX CSR is generated as 4 consecutive 32-bit physical registers,
+ * each one containing one byte of meaningful data.
+ *
+ * This function generates a series of single-byte reads with a proper offset
+ * and joins their results into a single multi-byte value.
+ */
+unsigned long litex_get_reg(void __iomem *reg, unsigned long reg_size)
+{
+ unsigned long shifted_data, shift, i;
+ unsigned long result = 0;
+
+ for (i = 0; i < reg_size; ++i) {
+ shifted_data = READ_LITEX_SUBREGISTER(reg, i);
+
+ shift = ((reg_size - i - 1) * LITEX_SUBREG_SIZE_BIT);
+ result |= (shifted_data << shift);
+ }
+
+ return result;
+}
+EXPORT_SYMBOL_GPL(litex_get_reg);
+
+#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;
+};
+
+static const struct of_device_id litex_soc_ctrl_of_match[] = {
+ {.compatible = "litex,soc-controller"},
+ {},
+};
+
+MODULE_DEVICE_TABLE(of, litex_soc_ctrl_of_match);
+
+static int litex_soc_ctrl_probe(struct platform_device *pdev)
+{
+ struct litex_soc_ctrl_device *soc_ctrl_dev;
+
+ 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);
+
+ return litex_check_csr_access(soc_ctrl_dev->base);
+}
+
+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,
+};
+
+module_platform_driver(litex_soc_ctrl_driver);
+MODULE_DESCRIPTION("LiteX SoC Controller driver");
+MODULE_AUTHOR("Antmicro <www.antmicro.com>");
+MODULE_LICENSE("GPL v2");