diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/spi/Kconfig | 28 | ||||
| -rw-r--r-- | drivers/spi/Makefile | 1 | ||||
| -rw-r--r-- | drivers/spi/spi-dw-bt1.c | 339 |
3 files changed, 368 insertions, 0 deletions
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig index db228121a40d..d2c976e55b8b 100644 --- a/drivers/spi/Kconfig +++ b/drivers/spi/Kconfig @@ -252,6 +252,34 @@ config SPI_DW_MMIO tristate "Memory-mapped io interface driver for DW SPI core" depends on HAS_IOMEM +config SPI_DW_BT1 + tristate "Baikal-T1 SPI driver for DW SPI core" + depends on MIPS_BAIKAL_T1 || COMPILE_TEST + help + Baikal-T1 SoC is equipped with three DW APB SSI-based MMIO SPI + controllers. Two of them are pretty much normal: with IRQ, DMA, + FIFOs of 64 words depth, 4x CSs, but the third one as being a + part of the Baikal-T1 System Boot Controller has got a very + limited resources: no IRQ, no DMA, only a single native + chip-select and Tx/Rx FIFO with just 8 words depth available. + The later one is normally connected to an external SPI-nor flash + of 128Mb (in general can be of bigger size). + +config SPI_DW_BT1_DIRMAP + bool "Directly mapped Baikal-T1 Boot SPI flash support" + depends on SPI_DW_BT1 + select MULTIPLEXER + select MUX_MMIO + help + Directly mapped SPI flash memory is an interface specific to the + Baikal-T1 System Boot Controller. It is a 16MB MMIO region, which + can be used to access a peripheral memory device just by + reading/writing data from/to it. Note that the system APB bus + will stall during each IO from/to the dirmap region until the + operation is finished. So try not to use it concurrently with + time-critical tasks (like the SPI memory operations implemented + in this driver). + endif config SPI_DLN2 diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile index cf955ea803cd..21dc75842aca 100644 --- a/drivers/spi/Makefile +++ b/drivers/spi/Makefile @@ -39,6 +39,7 @@ obj-$(CONFIG_SPI_DLN2) += spi-dln2.o obj-$(CONFIG_SPI_DESIGNWARE) += spi-dw.o spi-dw-y := spi-dw-core.o spi-dw-$(CONFIG_SPI_DW_DMA) += spi-dw-dma.o +obj-$(CONFIG_SPI_DW_BT1) += spi-dw-bt1.o obj-$(CONFIG_SPI_DW_MMIO) += spi-dw-mmio.o obj-$(CONFIG_SPI_DW_PCI) += spi-dw-pci.o obj-$(CONFIG_SPI_EFM32) += spi-efm32.o diff --git a/drivers/spi/spi-dw-bt1.c b/drivers/spi/spi-dw-bt1.c new file mode 100644 index 000000000000..f382dfad7842 --- /dev/null +++ b/drivers/spi/spi-dw-bt1.c @@ -0,0 +1,339 @@ +// SPDX-License-Identifier: GPL-2.0-only +// +// Copyright (C) 2020 BAIKAL ELECTRONICS, JSC +// +// Authors: +// Ramil Zaripov <Ramil.Zaripov@baikalelectronics.ru> +// Serge Semin <Sergey.Semin@baikalelectronics.ru> +// +// Baikal-T1 DW APB SPI and System Boot SPI driver +// + +#include <linux/clk.h> +#include <linux/cpumask.h> +#include <linux/err.h> +#include <linux/interrupt.h> +#include <linux/module.h> +#include <linux/mux/consumer.h> +#include <linux/of.h> +#include <linux/of_platform.h> +#include <linux/platform_device.h> +#include <linux/pm_runtime.h> +#include <linux/property.h> +#include <linux/slab.h> +#include <linux/spi/spi-mem.h> +#include <linux/spi/spi.h> + +#include "spi-dw.h" + +#define BT1_BOOT_DIRMAP 0 +#define BT1_BOOT_REGS 1 + +struct dw_spi_bt1 { + struct dw_spi dws; + struct clk *clk; + struct mux_control *mux; + +#ifdef CONFIG_SPI_DW_BT1_DIRMAP + void __iomem *map; + resource_size_t map_len; +#endif +}; +#define to_dw_spi_bt1(_ctlr) \ + container_of(spi_controller_get_devdata(_ctlr), struct dw_spi_bt1, dws) + +typedef int (*dw_spi_bt1_init_cb)(struct platform_device *pdev, + struct dw_spi_bt1 *dwsbt1); + +#ifdef CONFIG_SPI_DW_BT1_DIRMAP + +static int dw_spi_bt1_dirmap_create(struct spi_mem_dirmap_desc *desc) +{ + struct dw_spi_bt1 *dwsbt1 = to_dw_spi_bt1(desc->mem->spi->controller); + + if (!dwsbt1->map || + !dwsbt1->dws.mem_ops.supports_op(desc->mem, &desc->info.op_tmpl)) + return -EOPNOTSUPP; + + /* + * Make sure the requested region doesn't go out of the physically + * mapped flash memory bounds and the operation is read-only. + */ + if (desc->info.offset + desc->info.length > dwsbt1->map_len || + desc->info.op_tmpl.data.dir != SPI_MEM_DATA_IN) + return -EOPNOTSUPP; + + return 0; +} + +/* + * Directly mapped SPI memory region is only accessible in the dword chunks. + * That's why we have to create a dedicated read-method to copy data from there + * to the passed buffer. + */ +static void dw_spi_bt1_dirmap_copy_from_map(void *to, void __iomem *from, size_t len) +{ + size_t shift, chunk; + u32 data; + + /* + * We split the copying up into the next three stages: unaligned head, + * aligned body, unaligned tail. + */ + shift = (size_t)from & 0x3; + if (shift) { + chunk = min_t(size_t, 4 - shift, len); + data = readl_relaxed(from - shift); + memcpy(to, &data + shift, chunk); + from += chunk; + to += chunk; + len -= chunk; + } + + while (len >= 4) { + data = readl_relaxed(from); + memcpy(to, &data, 4); + from += 4; + to += 4; + len -= 4; + } + + if (len) { + data = readl_relaxed(from); + memcpy(to, &data, len); + } +} + +static ssize_t dw_spi_bt1_dirmap_read(struct spi_mem_dirmap_desc *desc, + u64 offs, size_t len, void *buf) +{ + struct dw_spi_bt1 *dwsbt1 = to_dw_spi_bt1(desc->mem->spi->controller); + struct dw_spi *dws = &dwsbt1->dws; + struct spi_mem *mem = desc->mem; + struct dw_spi_cfg cfg; + int ret; + + /* + * Make sure the requested operation length is valid. Truncate the + * length if it's greater than the length of the MMIO region. + */ + if (offs >= dwsbt1->map_len || !len) + return 0; + + len = min_t(size_t, len, dwsbt1->map_len - offs); + + /* Collect the controller configuration required by the operation */ + cfg.tmode = SPI_TMOD_EPROMREAD; + cfg.dfs = 8; + cfg.ndf = 4; + cfg.freq = mem->spi->max_speed_hz; + + /* Make sure the corresponding CS is de-asserted on transmission */ + dw_spi_set_cs(mem->spi, false); + + spi_enable_chip(dws, 0); + + dw_spi_update_config(dws, mem->spi, &cfg); + + spi_umask_intr(dws, SPI_INT_RXFI); + + spi_enable_chip(dws, 1); + + /* + * Enable the transparent mode of the System Boot Controller. + * The SPI core IO should have been locked before calling this method + * so noone would be touching the controller' registers during the + * dirmap operation. + */ + ret = mux_control_select(dwsbt1->mux, BT1_BOOT_DIRMAP); + if (ret) + return ret; + + dw_spi_bt1_dirmap_copy_from_map(buf, dwsbt1->map + offs, len); + + mux_control_deselect(dwsbt1->mux); + + dw_spi_set_cs(mem->spi, true); + + ret = dw_spi_check_status(dws, true); + + return ret ?: len; +} + +#endif /* CONFIG_SPI_DW_BT1_DIRMAP */ + +static int dw_spi_bt1_std_init(struct platform_device *pdev, + struct dw_spi_bt1 *dwsbt1) +{ + struct dw_spi *dws = &dwsbt1->dws; + + dws->irq = platform_get_irq(pdev, 0); + if (dws->irq < 0) + return dws->irq; + + dws->num_cs = 4; + + /* + * Baikal-T1 Normal SPI Controllers don't always keep up with full SPI + * bus speed especially when it comes to the concurrent access to the + * APB bus resources. Thus we have no choice but to set a constraint on + * the SPI bus frequency for the memory operations which require to + * read/write data as fast as possible. + */ + dws->max_mem_freq = 20000000U; + + dw_spi_dma_setup_generic(dws); + + return 0; +} + +static int dw_spi_bt1_sys_init(struct platform_device *pdev, + struct dw_spi_bt1 *dwsbt1) +{ + struct resource *mem __maybe_unused; + struct dw_spi *dws = &dwsbt1->dws; + + /* + * Baikal-T1 System Boot Controller is equipped with a mux, which + * switches between the directly mapped SPI flash access mode and + * IO access to the DW APB SSI registers. Note the mux controller + * must be setup to preserve the registers being accessible by default + * (on idle-state). + */ + dwsbt1->mux = devm_mux_control_get(&pdev->dev, NULL); + if (IS_ERR(dwsbt1->mux)) + return PTR_ERR(dwsbt1->mux); + + /* + * Directly mapped SPI flash memory is a 16MB MMIO region, which can be + * used to access a peripheral memory device just by reading/writing + * data from/to it. Note the system APB bus will stall during each IO + * from/to the dirmap region until the operation is finished. So don't + * use it concurrently with time-critical tasks (like the SPI memory + * operations implemented in the DW APB SSI driver). + */ +#ifdef CONFIG_SPI_DW_BT1_DIRMAP + mem = platform_get_resource(pdev, IORESOURCE_MEM, 1); + if (mem) { + dwsbt1->map = devm_ioremap_resource(&pdev->dev, mem); + if (!IS_ERR(dwsbt1->map)) { + dwsbt1->map_len = (mem->end - mem->start + 1); + dws->mem_ops.dirmap_create = dw_spi_bt1_dirmap_create; + dws->mem_ops.dirmap_read = dw_spi_bt1_dirmap_read; + } else { + dwsbt1->map = NULL; + } + } +#endif /* CONFIG_SPI_DW_BT1_DIRMAP */ + + /* + * There is no IRQ, no DMA and just one CS available on the System Boot + * SPI controller. + */ + dws->irq = IRQ_NOTCONNECTED; + dws->num_cs = 1; + + /* + * Baikal-T1 System Boot SPI Controller doesn't keep up with the full + * SPI bus speed due to relatively slow APB bus and races for it' + * resources from different CPUs. The situation is worsen by a small + * FIFOs depth (just 8 words). It works better in a single CPU mode + * though, but still tends to be not fast enough at low CPU + * frequencies. + */ + if (num_possible_cpus() > 1) + dws->max_mem_freq = 10000000U; + else + dws->max_mem_freq = 20000000U; + + return 0; +} + +static int dw_spi_bt1_probe(struct platform_device *pdev) +{ + dw_spi_bt1_init_cb init_func; + struct dw_spi_bt1 *dwsbt1; + struct resource *mem; + struct dw_spi *dws; + int ret; + + dwsbt1 = devm_kzalloc(&pdev->dev, sizeof(struct dw_spi_bt1), GFP_KERNEL); + if (!dwsbt1) + return -ENOMEM; + + dws = &dwsbt1->dws; + + dws->regs = devm_platform_get_and_ioremap_resource(pdev, 0, &mem); + if (IS_ERR(dws->regs)) + return PTR_ERR(dws->regs); + + dws->paddr = mem->start; + + dwsbt1->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(dwsbt1->clk)) + return PTR_ERR(dwsbt1->clk); + + ret = clk_prepare_enable(dwsbt1->clk); + if (ret) + return ret; + + dws->bus_num = pdev->id; + dws->reg_io_width = 4; + dws->max_freq = clk_get_rate(dwsbt1->clk); + if (!dws->max_freq) + goto err_disable_clk; + + init_func = device_get_match_data(&pdev->dev); + ret = init_func(pdev, dwsbt1); + if (ret) + goto err_disable_clk; + + pm_runtime_enable(&pdev->dev); + + ret = dw_spi_add_host(&pdev->dev, dws); + if (ret) + goto err_disable_clk; + + platform_set_drvdata(pdev, dwsbt1); + + return 0; + +err_disable_clk: + clk_disable_unprepare(dwsbt1->clk); + + return ret; +} + +static int dw_spi_bt1_remove(struct platform_device *pdev) +{ + struct dw_spi_bt1 *dwsbt1 = platform_get_drvdata(pdev); + + dw_spi_remove_host(&dwsbt1->dws); + + pm_runtime_disable(&pdev->dev); + + clk_disable_unprepare(dwsbt1->clk); + + return 0; +} + +static const struct of_device_id dw_spi_bt1_of_match[] = { + { .compatible = "baikal,bt1-ssi", .data = dw_spi_bt1_std_init}, + { .compatible = "baikal,bt1-sys-ssi", .data = dw_spi_bt1_sys_init}, + { } +}; +MODULE_DEVICE_TABLE(of, dw_spi_bt1_of_match); + +static struct platform_driver dw_spi_bt1_driver = { + .probe = dw_spi_bt1_probe, + .remove = dw_spi_bt1_remove, + .driver = { + .name = "bt1-sys-ssi", + .of_match_table = dw_spi_bt1_of_match, + }, +}; +module_platform_driver(dw_spi_bt1_driver); + +MODULE_AUTHOR("Serge Semin <Sergey.Semin@baikalelectronics.ru>"); +MODULE_DESCRIPTION("Baikal-T1 System Boot SPI Controller driver"); +MODULE_LICENSE("GPL v2"); |