Re: [PATCH v4 3/7] remoteproc: Add a remoteproc driver for the MT8183's APU

Bjorn Andersson
2022-03-14T22:03:00Z

On Fri 04 Mar 10:15 CST 2022, Alexandre Bailon wrote:

> This adds a driver to control the APU present in the MT8183.
> This loads the firmware and start the DSP.
>
> Signed-off-by: Alexandre Bailon <abailon@baylibre.com>
> ---
> drivers/remoteproc/Kconfig | 10 +
> drivers/remoteproc/Makefile | 1 +
> drivers/remoteproc/mtk_apu.c | 486 +++++++++++++++++++++++++++++++++++
> 3 files changed, 497 insertions(+)
> create mode 100644 drivers/remoteproc/mtk_apu.c
>
> diff --git a/drivers/remoteproc/Kconfig b/drivers/remoteproc/Kconfig
> index 341156e2a29b..959d24e9492c 100644
> --- a/drivers/remoteproc/Kconfig
> +++ b/drivers/remoteproc/Kconfig
> @@ -64,6 +64,16 @@ config MTK_SCP
>
> It's safe to say N here.
>
> +config MTK_APU
> + tristate "Mediatek APU remoteproc support"
> + depends on ARCH_MEDIATEK
> + depends on MTK_IOMMU
> + help
> + Say y to support the Mediatek's AI Processing Unit (APU) via
> + the remote processor framework.
> +
> + It's safe to say N here.
> +
> config OMAP_REMOTEPROC
> tristate "OMAP remoteproc support"
> depends on ARCH_OMAP4 || SOC_OMAP5 || SOC_DRA7XX
> diff --git a/drivers/remoteproc/Makefile b/drivers/remoteproc/Makefile
> index 0ac256b6c977..0ab4461c33af 100644
> --- a/drivers/remoteproc/Makefile
> +++ b/drivers/remoteproc/Makefile
> @@ -15,6 +15,7 @@ obj-$(CONFIG_IMX_REMOTEPROC) += imx_rproc.o
> obj-$(CONFIG_IMX_DSP_REMOTEPROC) += imx_dsp_rproc.o
> obj-$(CONFIG_INGENIC_VPU_RPROC) += ingenic_rproc.o
> obj-$(CONFIG_MTK_SCP) += mtk_scp.o mtk_scp_ipi.o
> +obj-$(CONFIG_MTK_APU) += mtk_apu.o
> obj-$(CONFIG_OMAP_REMOTEPROC) += omap_remoteproc.o
> obj-$(CONFIG_WKUP_M3_RPROC) += wkup_m3_rproc.o
> obj-$(CONFIG_DA8XX_REMOTEPROC) += da8xx_remoteproc.o
> diff --git a/drivers/remoteproc/mtk_apu.c b/drivers/remoteproc/mtk_apu.c
> new file mode 100644
> index 000000000000..867b4682b507
> --- /dev/null
> +++ b/drivers/remoteproc/mtk_apu.c
> @@ -0,0 +1,486 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2020 BayLibre SAS
> + */
> +
> +#include <linux/bitops.h>
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/interrupt.h>
> +#include <linux/iommu.h>
> +#include <linux/irq.h>
> +#include <linux/module.h>
> +#include <linux/of_reserved_mem.h>
> +#include <linux/platform_device.h>
> +#include <linux/remoteproc.h>
> +#include <linux/string.h>
> +
> +#include "remoteproc_internal.h"
> +
> +#define SW_RST (0x0000000C)
> +#define SW_RST_OCD_HALT_ON_RST BIT(12)
> +#define SW_RST_IPU_D_RST BIT(8)
> +#define SW_RST_IPU_B_RST BIT(4)
> +#define CORE_CTRL (0x00000110)
> +#define CORE_CTRL_PDEBUG_ENABLE BIT(31)
> +#define CORE_CTRL_SRAM_64K_iMEM (0x00 << 27)
> +#define CORE_CTRL_SRAM_96K_iMEM (0x01 << 27)
> +#define CORE_CTRL_SRAM_128K_iMEM (0x02 << 27)
> +#define CORE_CTRL_SRAM_192K_iMEM (0x03 << 27)
> +#define CORE_CTRL_SRAM_256K_iMEM (0x04 << 27)
> +#define CORE_CTRL_PBCLK_ENABLE BIT(26)
> +#define CORE_CTRL_RUN_STALL BIT(23)
> +#define CORE_CTRL_STATE_VECTOR_SELECT BIT(19)
> +#define CORE_CTRL_PIF_GATED BIT(17)
> +#define CORE_CTRL_NMI BIT(0)
> +#define CORE_XTENSA_INT (0x00000114)
> +#define CORE_CTL_XTENSA_INT (0x00000118)
> +#define CORE_DEFAULT0 (0x0000013C)
> +#define CORE_DEFAULT0_QOS_SWAP_0 (0x00 << 28)
> +#define CORE_DEFAULT0_QOS_SWAP_1 (0x01 << 28)
> +#define CORE_DEFAULT0_QOS_SWAP_2 (0x02 << 28)
> +#define CORE_DEFAULT0_QOS_SWAP_3 (0x03 << 28)
> +#define CORE_DEFAULT0_ARUSER_USE_IOMMU (0x10 << 23)
> +#define CORE_DEFAULT0_AWUSER_USE_IOMMU (0x10 << 18)
> +#define CORE_DEFAULT1 (0x00000140)
> +#define CORE_DEFAULT0_ARUSER_IDMA_USE_IOMMU (0x10 << 0)
> +#define CORE_DEFAULT0_AWUSER_IDMA_USE_IOMMU (0x10 << 5)
> +#define CORE_XTENSA_ALTRESETVEC (0x000001F8)
> +
> +#define VDEV_MEM_COUNT (3)
> +
> +#define APU_RESET_DELAY (27)
> +
> +struct mtk_apu_rproc {
> + struct device *dev;
> + void __iomem *base;
> + int irq;
> + unsigned int num_clks;
> + struct clk_bulk_data *clks;
> + struct iommu_domain *domain;
> + struct list_head mappings;
> +};
> +
> +static const char * const mt8183_clk_names[] = {
> + "ipu",
> + "axi",
> + "jtag"
> +};
> +
> +static int mtk_apu_iommu_map(struct rproc *rproc, struct rproc_mem_entry *entry)
> +{
> + struct mtk_apu_rproc *apu_rproc = rproc->priv;
> + struct device *dev = rproc->dev.parent;
> + struct rproc_mem_entry *mapping;
> + int ret;
> + u64 pa;
> +
> + /* vdev buffer and vring are already mapped */
> + if (strstr(entry->name, "vdev"))
> + return 0;
> +
> + mapping = kzalloc(sizeof(*mapping), GFP_KERNEL);
> + if (!mapping)
> + return -ENOMEM;
> +
> + if (!entry->va)
> + pa = entry->dma;
> + else
> + pa = rproc_va_to_pa(entry->va);
> +
> + ret = iommu_map(apu_rproc->domain, entry->da, pa, entry->len, entry->flags);

Can you please help me understand how this mapping differs from that
performed in rproc_alloc_carveout()?

What I think you're doing here seems very reasonable and as such I would
expect that this is what the core code does for us...

> + if (ret) {
> + dev_err(dev, "iommu_map failed: %d\n", ret);
> + goto free_mapping;
> + }
> +
> + mapping->da = entry->da;
> + mapping->len = entry->len;
> + list_add_tail(&mapping->node, &apu_rproc->mappings);
> +
> + return 0;
> +
> +free_mapping:
> + kfree(mapping);
> +
> + return ret;
> +}
> +
> +static void mtk_apu_iommu_unmap_all(struct rproc *rproc)
> +{
> + struct mtk_apu_rproc *apu_rproc = rproc->priv;
> + struct device *dev = rproc->dev.parent;
> + struct rproc_mem_entry *entry, *tmp;
> +
> + /* clean up iommu mapping entries */
> + list_for_each_entry_safe(entry, tmp, &apu_rproc->mappings, node) {
> + size_t unmapped;
> +
> + unmapped = iommu_unmap(apu_rproc->domain, entry->da, entry->len);
> + if (unmapped != entry->len) {
> + /* nothing much to do besides complaining */
> + dev_err(dev, "failed to unmap %zx/%zu\n", entry->len,
> + unmapped);
> + }
> +
> + list_del(&entry->node);
> + kfree(entry);
> + }
> +}
> +
> +static int mtk_apu_rproc_alloc_carveout(struct rproc *rproc,
> + struct rproc_mem_entry *mem)
> +{
> + int flags = IOMMU_READ | IOMMU_READ | IOMMU_NOEXEC;
> + struct device *dev = rproc->dev.parent;
> + int ret;
> +
> + struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
> +
> + mem->va = memremap(mem->dma, mem->len, MEMREMAP_WC);
> + if (IS_ERR_OR_NULL(mem->va)) {
> + dev_err(dev, "Unable to map memory region: %pa+%zu\n",
> + &mem->dma, mem->len);
> + return PTR_ERR(mem->va);
> + }
> +
> + ret = iommu_map(domain, mem->da, mem->dma, mem->len, flags);
> + if (ret)
> + memunmap(mem->va);
> +
> + return 0;
> +}
> +
> +static int mtk_apu_rproc_release_carveout(struct rproc *rproc,
> + struct rproc_mem_entry *mem)
> +{
> + struct mtk_apu_rproc *apu_rproc = rproc->priv;
> + struct device *dev = apu_rproc->dev;
> + struct iommu_domain *domain;
> + size_t unmapped;
> +
> + domain = iommu_get_domain_for_dev(dev);
> + unmapped = iommu_unmap(domain, mem->da, mem->len);
> + if (unmapped != mem->len) {
> + /* nothing much to do besides complaining */
> + dev_err(dev, "failed to unmap %zx/%zu\n", mem->len, unmapped);
> + }
> + memunmap(mem->va);
> +
> + return 0;
> +}
> +
> +static int mtk_apu_rproc_vdev_mem_init(struct rproc *rproc)
> +{
> + struct mtk_apu_rproc *apu_rproc = rproc->priv;
> + struct device *dev = apu_rproc->dev;
> + struct device_node *np = dev->of_node;
> + struct reserved_mem *rmem;
> + struct rproc_mem_entry *mem;
> + u32 da[VDEV_MEM_COUNT];
> + int ret;
> + int i;
> +
> + ret = of_property_read_u32_array(np, "memory-region-da", da, VDEV_MEM_COUNT);
> + if (ret)
> + return ret;
> +
> + for (i = 0; i < VDEV_MEM_COUNT; i++) {
> + struct device_node *target;
> + char *name;
> +
> + target = of_parse_phandle(np, "memory-region", i);
> + if (!target)
> + return -EINVAL;
> +
> + rmem = of_reserved_mem_lookup(target);
> + of_node_put(target);
> +
> + if (!rmem)
> + return -ENOMEM;
> +
> + ret = strcspn(rmem->name, "@");
> + if (!ret)
> + return -EINVAL;
> +
> + name = kstrndup(rmem->name, ret, GFP_KERNEL);
> + if (!name)
> + return -ENOMEM;
> +
> + mem = rproc_mem_entry_init(dev, NULL, rmem->base, rmem->size,
> + da[i],
> + mtk_apu_rproc_alloc_carveout,
> + mtk_apu_rproc_release_carveout,
> + name);
> + kfree(name);
> + if (!mem)
> + return -ENOMEM;
> +
> + rproc_add_carveout(rproc, mem);
> + }
> +
> + return 0;
> +}
> +
> +static int mtk_apu_rproc_prepare(struct rproc *rproc)
> +{
> + struct mtk_apu_rproc *apu_rproc = rproc->priv;
> + int ret;
> +
> + ret = clk_bulk_prepare_enable(apu_rproc->num_clks, apu_rproc->clks);
> + if (ret)
> + dev_err(apu_rproc->dev, "Failed to enable clocks\n");
> +
> + ret = mtk_apu_rproc_vdev_mem_init(rproc);
> + if (ret) {
> + dev_err(apu_rproc->dev, "Failed to init vdev memory\n");
> + clk_bulk_disable_unprepare(apu_rproc->num_clks, apu_rproc->clks);
> +
> + }
> +
> + return ret;
> +}
> +
> +static int mtk_apu_rproc_unprepare(struct rproc *rproc)
> +{
> + struct mtk_apu_rproc *apu_rproc = rproc->priv;
> +
> + clk_bulk_disable_unprepare(apu_rproc->num_clks, apu_rproc->clks);
> +
> + return 0;
> +}
> +
> +static int mtk_apu_rproc_start(struct rproc *rproc)
> +{
> + struct mtk_apu_rproc *apu_rproc = rproc->priv;
> + u32 core_ctrl;
> +
> + /* Set reset vector of APU firmware boot address */
> + writel(rproc->bootaddr, apu_rproc->base + CORE_XTENSA_ALTRESETVEC);
> +
> + /* Turn on the clocks and stall the APU */
> + core_ctrl = readl(apu_rproc->base + CORE_CTRL);
> + core_ctrl |= CORE_CTRL_PDEBUG_ENABLE | CORE_CTRL_PBCLK_ENABLE |
> + CORE_CTRL_STATE_VECTOR_SELECT | CORE_CTRL_RUN_STALL |
> + CORE_CTRL_PIF_GATED;
> + writel(core_ctrl, apu_rproc->base + CORE_CTRL);
> +
> + /* Reset the APU: this requires 27 ns to be effective on any platform */
> + writel(SW_RST_OCD_HALT_ON_RST | SW_RST_IPU_B_RST | SW_RST_IPU_D_RST,
> + apu_rproc->base + SW_RST);
> + ndelay(APU_RESET_DELAY);
> + writel(0, apu_rproc->base + SW_RST);
> +
> + core_ctrl &= ~CORE_CTRL_PIF_GATED;
> + writel(core_ctrl, apu_rproc->base + CORE_CTRL);
> +
> + /* Configure memory accesses to go through the IOMMU */
> + writel(CORE_DEFAULT0_AWUSER_USE_IOMMU | CORE_DEFAULT0_ARUSER_USE_IOMMU |
> + CORE_DEFAULT0_QOS_SWAP_1, apu_rproc->base + CORE_DEFAULT0);
> + writel(CORE_DEFAULT0_AWUSER_IDMA_USE_IOMMU |
> + CORE_DEFAULT0_ARUSER_IDMA_USE_IOMMU,
> + apu_rproc->base + CORE_DEFAULT1);
> +
> + /* Release the APU */
> + core_ctrl &= ~CORE_CTRL_RUN_STALL;
> + writel(core_ctrl, apu_rproc->base + CORE_CTRL);
> +
> + return 0;
> +}
> +
> +static int mtk_apu_rproc_stop(struct rproc *rproc)
> +{
> + struct mtk_apu_rproc *apu_rproc = rproc->priv;
> + u32 core_ctrl;
> +
> + core_ctrl = readl(apu_rproc->base + CORE_CTRL);
> + writel(core_ctrl | CORE_CTRL_RUN_STALL, apu_rproc->base + CORE_CTRL);
> +
> + mtk_apu_iommu_unmap_all(rproc);
> +
> + return 0;
> +}
> +
> +static void mtk_apu_rproc_kick(struct rproc *rproc, int vqid)
> +{
> + struct mtk_apu_rproc *apu_rproc = rproc->priv;
> +
> + writel(1 << vqid, apu_rproc->base + CORE_CTL_XTENSA_INT);
> +}
> +
> +static int mtk_apu_load(struct rproc *rproc, const struct firmware *fw)
> +
> +{
> + struct rproc_mem_entry *entry, *tmp;
> + int ret;
> +
> + ret = rproc_elf_load_segments(rproc, fw);
> + if (ret)
> + return ret;
> +
> + list_for_each_entry_safe(entry, tmp, &rproc->carveouts, node) {
> + ret = mtk_apu_iommu_map(rproc, entry);
> + if (ret)
> + goto err_unmap_all;
> + }
> +
> + return 0;
> +
> +err_unmap_all:
> + mtk_apu_iommu_unmap_all(rproc);
> +
> + return ret;
> +}
> +
> +static const struct rproc_ops mtk_apu_rproc_ops = {
> + .prepare = mtk_apu_rproc_prepare,
> + .unprepare = mtk_apu_rproc_unprepare,
> + .start = mtk_apu_rproc_start,
> + .stop = mtk_apu_rproc_stop,
> + .kick = mtk_apu_rproc_kick,
> + .load = mtk_apu_load,
> + .parse_fw = rproc_elf_load_rsc_table,
> + .find_loaded_rsc_table = rproc_elf_find_loaded_rsc_table,
> + .sanity_check = rproc_elf_sanity_check,
> + .get_boot_addr = rproc_elf_get_boot_addr,
> +};
> +
> +static irqreturn_t mtk_apu_rproc_callback(int irq, void *data)
> +{
> + struct rproc *rproc = data;
> + struct mtk_apu_rproc *apu_rproc = (struct mtk_apu_rproc *)rproc->priv;
> +
> + writel(1, apu_rproc->base + CORE_XTENSA_INT);
> +
> + return IRQ_WAKE_THREAD;
> +}
> +
> +static int mtk_apu_rproc_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct mtk_apu_rproc *apu_rproc;
> + struct rproc *rproc;
> + struct resource *res;
> + int ret;
> + int i;
> +
> + ret = of_property_count_elems_of_size(dev->of_node, "memory-region",
> + sizeof(phandle));
> + if (ret != VDEV_MEM_COUNT)
> + return -EINVAL;
> +
> + ret = of_property_count_elems_of_size(dev->of_node, "memory-region-da",
> + sizeof(u32));
> + if (ret != VDEV_MEM_COUNT)
> + return -EINVAL;
> +
> + rproc = rproc_alloc(dev, dev_name(dev), &mtk_apu_rproc_ops, NULL,
> + sizeof(*apu_rproc));
> + if (!rproc)
> + return -ENOMEM;
> +
> + rproc->recovery_disabled = true;
> + rproc->has_iommu = false;
> + rproc->auto_boot = false;
> +
> + apu_rproc = rproc->priv;
> + apu_rproc->dev = dev;
> + INIT_LIST_HEAD(&apu_rproc->mappings);
> +
> + platform_set_drvdata(pdev, rproc);
> +
> + apu_rproc->domain = iommu_get_domain_for_dev(dev);
> + if (!apu_rproc->domain) {
> + ret = -ENODEV;
> + goto free_rproc;
> + }
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + apu_rproc->base = devm_ioremap_resource(dev, res);

Please use devm_platform_ioremap_resource()

> + if (IS_ERR(apu_rproc->base)) {
> + dev_err(dev, "Failed to map mmio\n");
> + ret = PTR_ERR(apu_rproc->base);
> + goto free_rproc;
> + }
> +
> + apu_rproc->irq = platform_get_irq(pdev, 0);
> + if (apu_rproc->irq < 0) {
> + ret = apu_rproc->irq;
> + goto free_rproc;
> + }
> +
> + apu_rproc->domain = iommu_get_domain_for_dev(dev);

You did this ~20 lines above already.

> + if (!apu_rproc->domain) {
> + ret = -ENODEV;
> + goto free_rproc;
> + }
> +
> + ret = devm_request_threaded_irq(dev, apu_rproc->irq,
> + mtk_apu_rproc_callback, handle_event,
> + IRQF_SHARED | IRQF_ONESHOT,
> + NULL, rproc);
> + if (ret) {
> + dev_err(dev, "devm_request_threaded_irq error: %d\n", ret);
> + goto free_rproc;
> + }
> +
> + apu_rproc->num_clks = ARRAY_SIZE(mt8183_clk_names);
> + apu_rproc->clks = devm_kcalloc(dev, apu_rproc->num_clks,
> + sizeof(*apu_rproc->clks), GFP_KERNEL);

You know that this is going to be ARRAY_SIZE(mt8183_clk_names), so you
could make clks a statically sized array instead...

> + for (i = 0; i < apu_rproc->num_clks; ++i)
> + apu_rproc->clks[i].id = mt8183_clk_names[i];
> +
> + ret = devm_clk_bulk_get(dev, apu_rproc->num_clks, apu_rproc->clks);
> + if (ret) {
> + dev_err(dev, "Failed to get clocks\n");

Please use dev_err_probe()

> + goto free_rproc;
> + }
> +
> + ret = rproc_add(rproc);
> + if (ret) {
> + dev_err(dev, "rproc_add failed: %d\n", ret);
> + goto free_rproc;
> + }
> +
> + return 0;
> +
> +free_rproc:
> + rproc_free(rproc);
> +
> + return ret;
> +}
> +
> +static int mtk_apu_rproc_remove(struct platform_device *pdev)
> +{
> + struct rproc *rproc = platform_get_drvdata(pdev);
> + struct mtk_apu_rproc *apu_rproc = (struct mtk_apu_rproc *)rproc->priv;
> + struct device *dev = &pdev->dev;
> +
> + disable_irq(apu_rproc->irq);
> +
> + rproc_del(rproc);
> + of_reserved_mem_device_release(dev);

Iiuc this is the reverse of of_reserved_mem_device_init_by_*(), but you
do of_reserved_mem_lookup(). So I don't think you need this.

I'm not sure what your irq handler actually does, is there a specific
reason for you to call disable_irq()?

If not you could use devm_rproc_* and get rid of the remove function...

> + rproc_free(rproc);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id mtk_apu_rproc_of_match[] = {
> + { .compatible = "mediatek,mt8183-apu", },
> + { /* sentinel */ },
> +};
> +MODULE_DEVICE_TABLE(of, mtk_apu_rproc_of_match);
> +
> +static struct platform_driver mtk_apu_rproc_driver = {
> + .probe = mtk_apu_rproc_probe,
> + .remove = mtk_apu_rproc_remove,
> + .driver = {
> + .name = "mtk_apu-rproc",
> + .of_match_table = of_match_ptr(mtk_apu_rproc_of_match),

of_match_ptr() will be dropped in builds without CONFIG_OF and we will
then get a warning that mtk_apu_rproc_of_match isn't referenced.

Just leave it around it won't cost you anything.

Thanks,
Bjorn

> + },
> +};
> +module_platform_driver(mtk_apu_rproc_driver);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_AUTHOR("Alexandre Bailon");
> +MODULE_DESCRIPTION("MTK APU Remote Processor control driver");
> --
> 2.34.1
>