Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki On 2017-09-22 10:31, Pierre-Yves MORDRET wrote: > This patch implements the STM32 DMAMUX driver. > > The DMAMUX request multiplexer allows routing a DMA request line between > the peripherals and the DMA controllers of the product. The routing > function is ensured by a programmable multi-channel DMA request line > multiplexer. Each channel selects a unique DMA request line, > unconditionally or synchronously with events from its DMAMUX > synchronization inputs. The DMAMUX may also be used as a DMA request > generator from programmable events on its input trigger signals > > Signed-off-by: M'boumba Cedric Madianga <[email protected]> > Signed-off-by: Pierre-Yves MORDRET <[email protected]> Reviewed-by: Peter Ujfalusi <[email protected]> > --- > Version history: > v5: > * Set selected channel ID within a lock to avoid race condition. > Release if any error occurs > v4: > * Get rid of st,dmamux property and custom API between STM32 > DMAMUX and DMA. > DMAMUX will read DMA masters from Device Tree from now on. > Merely one DMAMUX node is needed now. > * Only STM32 DMA are allowed to be connected onto DMAMUX > * channelID is computed locally within the driver and crafted in > dma_psec to be passed toward DMA master. > DMAMUX router sorts out which DMA master will serve the > request automatically. > * This version forbids the use of DMA in standalone and DMAMUX at > the same time : all clients need to be connected either on DMA > or DMAMUX ; no mix up > v3: > * change compatible to st,stm32h7-dmamux to be mode SoC specific > v2: > * Dynamic channelID allocation. > * Change of_property_... by device_property. > * New clock management. > * DMAMUX Configuration API. > --- > --- > drivers/dma/Kconfig | 9 ++ > drivers/dma/Makefile | 1 + > drivers/dma/stm32-dmamux.c | 327 > +++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 337 insertions(+) > create mode 100644 drivers/dma/stm32-dmamux.c > > diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig > index fadc4d8..04e381b 100644 > --- a/drivers/dma/Kconfig > +++ b/drivers/dma/Kconfig > @@ -483,6 +483,15 @@ config STM32_DMA > If you have a board based on such a MCU and wish to use DMA say Y > here. > > +config STM32_DMAMUX > + bool "STMicroelectronics STM32 dma multiplexer support" > + depends on STM32_DMA || COMPILE_TEST > + help > + Enable support for the on-chip DMA multiplexer on STMicroelectronics > + STM32 MCUs. > + If you have a board based on such a MCU and wish to use DMAMUX say Y > + here. > + > config S3C24XX_DMAC > bool "Samsung S3C24XX DMA support" > depends on ARCH_S3C24XX || COMPILE_TEST > diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile > index f08f8de..a145ad1 100644 > --- a/drivers/dma/Makefile > +++ b/drivers/dma/Makefile > @@ -59,6 +59,7 @@ obj-$(CONFIG_RENESAS_DMA) += sh/ > obj-$(CONFIG_SIRF_DMA) += sirf-dma.o > obj-$(CONFIG_STE_DMA40) += ste_dma40.o ste_dma40_ll.o > obj-$(CONFIG_STM32_DMA) += stm32-dma.o > +obj-$(CONFIG_STM32_DMAMUX) += stm32-dmamux.o > obj-$(CONFIG_S3C24XX_DMAC) += s3c24xx-dma.o > obj-$(CONFIG_TXX9_DMAC) += txx9dmac.o > obj-$(CONFIG_TEGRA20_APB_DMA) += tegra20-apb-dma.o > diff --git a/drivers/dma/stm32-dmamux.c b/drivers/dma/stm32-dmamux.c > new file mode 100644 > index 0000000..22812e7 > --- /dev/null > +++ b/drivers/dma/stm32-dmamux.c > @@ -0,0 +1,327 @@ > +/* > + * > + * Copyright (C) STMicroelectronics SA 2017 > + * Author(s): M'boumba Cedric Madianga <[email protected]> > + * Pierre-Yves Mordret <[email protected]> > + * > + * License terms: GPL V2.0. > + * > + * This program is free software; you can redistribute it and/or modify it > + * under the terms of the GNU General Public License version 2 as published > by > + * the Free Software Foundation. > + * > + * This program is distributed in the hope that it will be useful, but > + * WITHOUT ANY WARRANTY; without even the implied warranty of > MERCHANTABILITY or > + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for > more > + * details. > + * > + * DMA Router driver for STM32 DMA MUX > + * > + * Based on TI DMA Crossbar driver > + * > + */ > + > +#include <linux/clk.h> > +#include <linux/delay.h> > +#include <linux/err.h> > +#include <linux/init.h> > +#include <linux/module.h> > +#include <linux/of_device.h> > +#include <linux/of_dma.h> > +#include <linux/reset.h> > +#include <linux/slab.h> > +#include <linux/spinlock.h> > + > +#define STM32_DMAMUX_CCR(x) (0x4 * (x)) > +#define STM32_DMAMUX_MAX_DMA_REQUESTS 32 > +#define STM32_DMAMUX_MAX_REQUESTS 255 > + > +struct stm32_dmamux { > + u32 master; > + u32 request; > + u32 chan_id; > +}; > + > +struct stm32_dmamux_data { > + struct dma_router dmarouter; > + struct clk *clk; > + struct reset_control *rst; > + void __iomem *iomem; > + u32 dma_requests; /* Number of DMA requests connected to DMAMUX */ > + u32 dmamux_requests; /* Number of DMA requests routed toward DMAs */ > + spinlock_t lock; /* Protects register access */ > + unsigned long *dma_inuse; /* Used DMA channel */ > + u32 dma_reqs[]; /* Number of DMA Request per DMA masters. > + * [0] holds number of DMA Masters. > + * To be kept at very end end of this structure > + */ > +}; > + > +static inline u32 stm32_dmamux_read(void __iomem *iomem, u32 reg) > +{ > + return readl_relaxed(iomem + reg); > +} > + > +static inline void stm32_dmamux_write(void __iomem *iomem, u32 reg, u32 val) > +{ > + writel_relaxed(val, iomem + reg); > +} > + > +static void stm32_dmamux_free(struct device *dev, void *route_data) > +{ > + struct stm32_dmamux_data *dmamux = dev_get_drvdata(dev); > + struct stm32_dmamux *mux = route_data; > + unsigned long flags; > + > + /* Clear dma request */ > + spin_lock_irqsave(&dmamux->lock, flags); > + > + stm32_dmamux_write(dmamux->iomem, STM32_DMAMUX_CCR(mux->chan_id), 0); > + clear_bit(mux->chan_id, dmamux->dma_inuse); > + > + if (!IS_ERR(dmamux->clk)) > + clk_disable(dmamux->clk); > + > + spin_unlock_irqrestore(&dmamux->lock, flags); > + > + dev_dbg(dev, "Unmapping DMAMUX(%u) to DMA%u(%u)\n", > + mux->request, mux->master, mux->chan_id); > + > + kfree(mux); > +} > + > +static void *stm32_dmamux_route_allocate(struct of_phandle_args *dma_spec, > + struct of_dma *ofdma) > +{ > + struct platform_device *pdev = of_find_device_by_node(ofdma->of_node); > + struct stm32_dmamux_data *dmamux = platform_get_drvdata(pdev); > + struct stm32_dmamux *mux; > + u32 i, min, max; > + int ret; > + unsigned long flags; > + > + if (dma_spec->args_count != 3) { > + dev_err(&pdev->dev, "invalid number of dma mux args\n"); > + return ERR_PTR(-EINVAL); > + } > + > + if (dma_spec->args[0] > dmamux->dmamux_requests) { > + dev_err(&pdev->dev, "invalid mux request number: %d\n", > + dma_spec->args[0]); > + return ERR_PTR(-EINVAL); > + } > + > + mux = kzalloc(sizeof(*mux), GFP_KERNEL); > + if (!mux) > + return ERR_PTR(-ENOMEM); > + > + spin_lock_irqsave(&dmamux->lock, flags); > + mux->chan_id = find_first_zero_bit(dmamux->dma_inuse, > + dmamux->dma_requests); > + set_bit(mux->chan_id, dmamux->dma_inuse); > + spin_unlock_irqrestore(&dmamux->lock, flags); > + > + if (mux->chan_id == dmamux->dma_requests) { > + dev_err(&pdev->dev, "Run out of free DMA requests\n"); > + ret = -ENOMEM; > + goto error; > + } > + > + /* Look for DMA Master */ > + for (i = 1, min = 0, max = dmamux->dma_reqs[i]; > + i <= dmamux->dma_reqs[0]; > + min += dmamux->dma_reqs[i], max += dmamux->dma_reqs[++i]) > + if (mux->chan_id < max) > + break; > + mux->master = i - 1; > + > + /* The of_node_put() will be done in of_dma_router_xlate function */ > + dma_spec->np = of_parse_phandle(ofdma->of_node, "dma-masters", i - 1); > + if (!dma_spec->np) { > + dev_err(&pdev->dev, "can't get dma master\n"); > + ret = -EINVAL; > + goto error; > + } > + > + /* Set dma request */ > + spin_lock_irqsave(&dmamux->lock, flags); > + if (!IS_ERR(dmamux->clk)) { > + ret = clk_enable(dmamux->clk); > + if (ret < 0) { > + spin_unlock_irqrestore(&dmamux->lock, flags); > + dev_err(&pdev->dev, "clk_prep_enable issue: %d\n", ret); > + goto error; > + } > + } > + spin_unlock_irqrestore(&dmamux->lock, flags); > + > + mux->request = dma_spec->args[0]; > + > + /* craft DMA spec */ > + dma_spec->args[3] = dma_spec->args[2]; > + dma_spec->args[2] = dma_spec->args[1]; > + dma_spec->args[1] = 0; > + dma_spec->args[0] = mux->chan_id - min; > + dma_spec->args_count = 4; > + > + stm32_dmamux_write(dmamux->iomem, STM32_DMAMUX_CCR(mux->chan_id), > + mux->request); > + dev_dbg(&pdev->dev, "Mapping DMAMUX(%u) to DMA%u(%u)\n", > + mux->request, mux->master, mux->chan_id); > + > + return mux; > + > +error: > + clear_bit(mux->chan_id, dmamux->dma_inuse); > + kfree(mux); > + return ERR_PTR(ret); > +} > + > +static const struct of_device_id stm32_stm32dma_master_match[] = { > + { .compatible = "st,stm32-dma", }, > + {}, > +}; > + > +static int stm32_dmamux_probe(struct platform_device *pdev) > +{ > + struct device_node *node = pdev->dev.of_node; > + const struct of_device_id *match; > + struct device_node *dma_node; > + struct stm32_dmamux_data *stm32_dmamux; > + struct resource *res; > + void __iomem *iomem; > + int i, count, ret; > + u32 dma_req; > + > + if (!node) > + return -ENODEV; > + > + count = device_property_read_u32_array(&pdev->dev, "dma-masters", > + NULL, 0); > + if (count < 0) { > + dev_err(&pdev->dev, "Can't get DMA master(s) node\n"); > + return -ENODEV; > + } > + > + stm32_dmamux = devm_kzalloc(&pdev->dev, sizeof(*stm32_dmamux) + > + sizeof(u32) * (count + 1), GFP_KERNEL); > + if (!stm32_dmamux) > + return -ENOMEM; > + > + dma_req = 0; > + for (i = 1; i <= count; i++) { > + dma_node = of_parse_phandle(node, "dma-masters", i - 1); > + > + match = of_match_node(stm32_stm32dma_master_match, dma_node); > + if (!match) { > + dev_err(&pdev->dev, "DMA master is not supported\n"); > + of_node_put(dma_node); > + return -EINVAL; > + } > + > + if (of_property_read_u32(dma_node, "dma-requests", > + &stm32_dmamux->dma_reqs[i])) { > + dev_info(&pdev->dev, > + "Missing MUX output information, using %u.\n", > + STM32_DMAMUX_MAX_DMA_REQUESTS); > + stm32_dmamux->dma_reqs[i] = > + STM32_DMAMUX_MAX_DMA_REQUESTS; > + } > + dma_req += stm32_dmamux->dma_reqs[i]; > + of_node_put(dma_node); > + } > + > + if (dma_req > STM32_DMAMUX_MAX_DMA_REQUESTS) { > + dev_err(&pdev->dev, "Too many DMA Master Requests to manage\n"); > + return -ENODEV; > + } > + > + stm32_dmamux->dma_requests = dma_req; > + stm32_dmamux->dma_reqs[0] = count; > + stm32_dmamux->dma_inuse = devm_kcalloc(&pdev->dev, > + BITS_TO_LONGS(dma_req), > + sizeof(unsigned long), > + GFP_KERNEL); > + if (!stm32_dmamux->dma_inuse) > + return -ENOMEM; > + > + if (device_property_read_u32(&pdev->dev, "dma-requests", > + &stm32_dmamux->dmamux_requests)) { > + stm32_dmamux->dmamux_requests = STM32_DMAMUX_MAX_REQUESTS; > + dev_warn(&pdev->dev, "DMAMUX defaulting on %u requests\n", > + stm32_dmamux->dmamux_requests); > + } > + > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + if (!res) > + return -ENODEV; > + > + iomem = devm_ioremap_resource(&pdev->dev, res); > + if (!iomem) > + return -ENOMEM; > + > + spin_lock_init(&stm32_dmamux->lock); > + > + stm32_dmamux->clk = devm_clk_get(&pdev->dev, NULL); > + if (IS_ERR(stm32_dmamux->clk)) { > + ret = PTR_ERR(stm32_dmamux->clk); > + if (ret == -EPROBE_DEFER) > + dev_info(&pdev->dev, "Missing controller clock\n"); > + return ret; > + } > + > + stm32_dmamux->rst = devm_reset_control_get(&pdev->dev, NULL); > + if (!IS_ERR(stm32_dmamux->rst)) { > + reset_control_assert(stm32_dmamux->rst); > + udelay(2); > + reset_control_deassert(stm32_dmamux->rst); > + } > + > + stm32_dmamux->iomem = iomem; > + stm32_dmamux->dmarouter.dev = &pdev->dev; > + stm32_dmamux->dmarouter.route_free = stm32_dmamux_free; > + > + platform_set_drvdata(pdev, stm32_dmamux); > + > + if (!IS_ERR(stm32_dmamux->clk)) { > + ret = clk_prepare_enable(stm32_dmamux->clk); > + if (ret < 0) { > + dev_err(&pdev->dev, "clk_prep_enable error: %d\n", ret); > + return ret; > + } > + } > + > + /* Reset the dmamux */ > + for (i = 0; i < stm32_dmamux->dma_requests; i++) > + stm32_dmamux_write(stm32_dmamux->iomem, STM32_DMAMUX_CCR(i), 0); > + > + if (!IS_ERR(stm32_dmamux->clk)) > + clk_disable(stm32_dmamux->clk); > + > + return of_dma_router_register(node, stm32_dmamux_route_allocate, > + &stm32_dmamux->dmarouter); > +} > + > +static const struct of_device_id stm32_dmamux_match[] = { > + { .compatible = "st,stm32h7-dmamux" }, > + {}, > +}; > + > +static struct platform_driver stm32_dmamux_driver = { > + .probe = stm32_dmamux_probe, > + .driver = { > + .name = "stm32-dmamux", > + .of_match_table = stm32_dmamux_match, > + }, > +}; > + > +static int __init stm32_dmamux_init(void) > +{ > + return platform_driver_register(&stm32_dmamux_driver); > +} > +arch_initcall(stm32_dmamux_init); > + > +MODULE_DESCRIPTION("DMA Router driver for STM32 DMA MUX"); > +MODULE_AUTHOR("M'boumba Cedric Madianga <[email protected]>"); > +MODULE_AUTHOR("Pierre-Yves Mordret <[email protected]>"); > +MODULE_LICENSE("GPL v2");
