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[77.65.79.196]) by smtp.gmail.com with ESMTPSA id o4sm426080lfb.52.2020.07.15.04.07.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Jul 2020 04:07:44 -0700 (PDT) Date: Wed, 15 Jul 2020 13:07:39 +0200 From: Mateusz Holenko To: Rob Herring , Mark Rutland , Greg Kroah-Hartman , Jiri Slaby , devicetree@vger.kernel.org, linux-serial@vger.kernel.org Cc: Stafford Horne , Karol Gugala , Mateusz Holenko , Mauro Carvalho Chehab , "David S. Miller" , "Paul E. McKenney" , Filip Kokosinski , Pawel Czarnecki , Joel Stanley , Jonathan Cameron , Maxime Ripard , Shawn Guo , Heiko Stuebner , Sam Ravnborg , Icenowy Zheng , Laurent Pinchart , linux-kernel@vger.kernel.org, "Gabriel L. Somlo" Subject: [PATCH v8 3/5] drivers/soc/litex: add LiteX SoC Controller driver Message-ID: <20200715130641.1953227-3-mholenko@antmicro.com> References: <20200715130641.1953227-0-mholenko@antmicro.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200715130641.1953227-0-mholenko@antmicro.com> Sender: linux-serial-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org From: Pawel Czarnecki This commit adds driver for the FPGA-based LiteX SoC Controller from LiteX SoC builder. Co-developed-by: Mateusz Holenko Signed-off-by: Mateusz Holenko Signed-off-by: Pawel Czarnecki --- Notes: Changes in v8: - removed `litex_check_accessors()` helper function - added crashing (BUG) on the failed LiteX CSR access test No changes in v7. Changes in v6: - added dependency on OF || COMPILE_TEST - used le32_to_cpu(readl(addr)) instead of __raw_readl and writel(cpu_to_le32(value), addr) instead of __raw_writel to take advantage of memory barriers provided by readl/writel Changes in v5: - removed helper accessors and used __raw_readl/__raw_writel instead - fixed checking for errors in litex_soc_ctrl_probe Changes in v4: - fixed indent in Kconfig's help section - fixed copyright header - changed compatible to "litex,soc-controller" - simplified litex_soc_ctrl_probe - removed unnecessary litex_soc_ctrl_remove This commit has been introduced in v3 of the patchset. It includes a simplified version of common 'litex.h' header introduced in v2 of the patchset. MAINTAINERS | 2 + drivers/soc/Kconfig | 1 + drivers/soc/Makefile | 1 + drivers/soc/litex/Kconfig | 15 +++ drivers/soc/litex/Makefile | 3 + drivers/soc/litex/litex_soc_ctrl.c | 192 +++++++++++++++++++++++++++++ include/linux/litex.h | 24 ++++ 7 files changed, 238 insertions(+) create mode 100644 drivers/soc/litex/Kconfig create mode 100644 drivers/soc/litex/Makefile create mode 100644 drivers/soc/litex/litex_soc_ctrl.c create mode 100644 include/linux/litex.h diff --git a/MAINTAINERS b/MAINTAINERS index 39be98db7418..4d70a1b22a87 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -9840,6 +9840,8 @@ M: Karol Gugala M: Mateusz Holenko S: Maintained F: Documentation/devicetree/bindings/*/litex,*.yaml +F: drivers/soc/litex/litex_soc_ctrl.c +F: include/linux/litex.h LIVE PATCHING M: Josh Poimboeuf 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 36452bed86ef..0b16108823ef 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..c974ec3846bc --- /dev/null +++ b/drivers/soc/litex/Kconfig @@ -0,0 +1,15 @@ +# SPDX-License_Identifier: GPL-2.0 + +menu "Enable LiteX SoC Builder specific drivers" + +config LITEX_SOC_CONTROLLER + tristate "Enable LiteX SoC Controller driver" + depends on OF || COMPILE_TEST + 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_SOC_CONTROLLER. + +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..08330c9872b0 --- /dev/null +++ b/drivers/soc/litex/litex_soc_ctrl.c @@ -0,0 +1,192 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * LiteX SoC Controller Driver + * + * Copyright (C) 2020 Antmicro + * + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* + * The parameters below are true for LiteX SoC + * configured for 8-bit CSR Bus, 32-bit aligned. + * + * Supporting other configurations will require + * extending the logic in this header. + */ +#define LITEX_REG_SIZE 0x4 +#define LITEX_SUBREG_SIZE 0x1 +#define LITEX_SUBREG_SIZE_BIT (LITEX_SUBREG_SIZE * 8) + +static DEFINE_SPINLOCK(csr_lock); + +/* + * 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. + */ +void litex_set_reg(void __iomem *reg, unsigned long reg_size, + unsigned long val) +{ + unsigned long shifted_data, shift, i; + unsigned long flags; + + spin_lock_irqsave(&csr_lock, flags); + + for (i = 0; i < reg_size; ++i) { + shift = ((reg_size - i - 1) * LITEX_SUBREG_SIZE_BIT); + shifted_data = val >> shift; + + writel(cpu_to_le32(shifted_data), reg + (LITEX_REG_SIZE * i)); + } + + spin_unlock_irqrestore(&csr_lock, flags); +} + +unsigned long litex_get_reg(void __iomem *reg, unsigned long reg_size) +{ + unsigned long shifted_data, shift, i; + unsigned long result = 0; + unsigned long flags; + + spin_lock_irqsave(&csr_lock, flags); + + for (i = 0; i < reg_size; ++i) { + shifted_data = le32_to_cpu(readl(reg + (LITEX_REG_SIZE * i))); + + shift = ((reg_size - i - 1) * LITEX_SUBREG_SIZE_BIT); + result |= (shifted_data << shift); + } + + spin_unlock_irqrestore(&csr_lock, flags); + + return result; +} + +#define SCRATCH_REG_OFF 0x04 +#define SCRATCH_REG_SIZE 4 +#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_get_reg(reg_addr + SCRATCH_REG_OFF, SCRATCH_REG_SIZE); + + if (reg != SCRATCH_REG_VALUE) { + panic("Scratch register read error! Expected: 0x%x but got: 0x%lx", + SCRATCH_REG_VALUE, reg); + return -EINVAL; + } + + litex_set_reg(reg_addr + SCRATCH_REG_OFF, + SCRATCH_REG_SIZE, SCRATCH_TEST_VALUE); + reg = litex_get_reg(reg_addr + SCRATCH_REG_OFF, SCRATCH_REG_SIZE); + + if (reg != SCRATCH_TEST_VALUE) { + panic("Scratch register write error! Expected: 0x%x but got: 0x%lx", + SCRATCH_TEST_VALUE, reg); + return -EINVAL; + } + + /* restore original value of the SCRATCH register */ + litex_set_reg(reg_addr + SCRATCH_REG_OFF, + SCRATCH_REG_SIZE, SCRATCH_REG_VALUE); + + /* Set flag for other drivers */ + 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) +{ + int result; + struct device *dev; + struct device_node *node; + struct litex_soc_ctrl_device *soc_ctrl_dev; + + dev = &pdev->dev; + node = dev->of_node; + if (!node) + return -ENODEV; + + soc_ctrl_dev = devm_kzalloc(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); + + result = litex_check_csr_access(soc_ctrl_dev->base); + if (result) { + // LiteX CSRs access is broken which means that + // none of LiteX drivers will most probably + // operate correctly + BUG(); + } + + 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, +}; + +module_platform_driver(litex_soc_ctrl_driver); +MODULE_DESCRIPTION("LiteX SoC Controller driver"); +MODULE_AUTHOR("Antmicro "); +MODULE_LICENSE("GPL v2"); diff --git a/include/linux/litex.h b/include/linux/litex.h new file mode 100644 index 000000000000..72061018c172 --- /dev/null +++ b/include/linux/litex.h @@ -0,0 +1,24 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Common LiteX header providing + * helper functions for accessing CSRs. + * + * Implementation of the functions is provided by + * the LiteX SoC Controller driver. + * + * Copyright (C) 2019-2020 Antmicro + */ + +#ifndef _LINUX_LITEX_H +#define _LINUX_LITEX_H + +#include +#include +#include + +void litex_set_reg(void __iomem *reg, unsigned long reg_sz, unsigned long val); + +unsigned long litex_get_reg(void __iomem *reg, unsigned long reg_sz); + + +#endif /* _LINUX_LITEX_H */ -- 2.25.1