diff options
Diffstat (limited to 'drivers/dma/stm32-dmamux.c')
| -rw-r--r-- | drivers/dma/stm32-dmamux.c | 327 |
1 files changed, 327 insertions, 0 deletions
diff --git a/drivers/dma/stm32-dmamux.c b/drivers/dma/stm32-dmamux.c new file mode 100644 index 0000000..d5db0f6 --- /dev/null +++ b/drivers/dma/stm32-dmamux.c @@ -0,0 +1,327 @@ +/* + * + * Copyright (C) STMicroelectronics SA 2017 + * Author(s): M'boumba Cedric Madianga <cedric.madianga@gmail.com> + * Pierre-Yves Mordret <pierre-yves.mordret@st.com> + * + * 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 (IS_ERR(iomem)) + return PTR_ERR(iomem); + + 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 <cedric.madianga@gmail.com>"); +MODULE_AUTHOR("Pierre-Yves Mordret <pierre-yves.mordret@st.com>"); +MODULE_LICENSE("GPL v2"); |
