Re: [PATCH v4 5/7] interconnect: qcom: Add msm8916 interconnect provider driver

[Evan Green <evgreen@chromium.org>]

Hi Georgi,

On Fri, Mar 9, 2018 at 1:11 PM Georgi Djakov <georgi.djakov@linaro.org>
wrote:

> Add driver for the Qualcomm interconnect buses found in msm8916 based
> platforms.

> Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
> ---
>    drivers/interconnect/Kconfig        |   5 +
>    drivers/interconnect/Makefile       |   1 +
>    drivers/interconnect/qcom/Kconfig   |  11 +
>    drivers/interconnect/qcom/Makefile  |   2 +
>    drivers/interconnect/qcom/msm8916.c | 482
++++++++++++++++++++++++++++++++++++
>    include/linux/interconnect/qcom.h   | 350 ++++++++++++++++++++++++++
>    6 files changed, 851 insertions(+)
>    create mode 100644 drivers/interconnect/qcom/Kconfig
>    create mode 100644 drivers/interconnect/qcom/msm8916.c
>    create mode 100644 include/linux/interconnect/qcom.h
...
> diff --git a/drivers/interconnect/qcom/msm8916.c
b/drivers/interconnect/qcom/msm8916.c
> new file mode 100644
> index 000000000000..d5b54f8261c8
> --- /dev/null
> +++ b/drivers/interconnect/qcom/msm8916.c
...
> +static int qnoc_probe(struct platform_device *pdev)
> +{
> +       const struct qcom_icc_desc *desc;
> +       struct qcom_icc_node **qnodes;
> +       struct qcom_icc_provider *qp;
> +       struct resource *res;
> +       struct icc_provider *provider;
> +       size_t num_nodes, i;
> +       int ret;
> +
> +       /* wait for RPM */
> +       if (!qcom_icc_rpm_smd_available())
> +               return -EPROBE_DEFER;
> +
> +       desc = of_device_get_match_data(&pdev->dev);
> +       if (!desc)
> +               return -EINVAL;
> +
> +       qnodes = desc->nodes;
> +       num_nodes = desc->num_nodes;
> +
> +       qp = devm_kzalloc(&pdev->dev, sizeof(*qp), GFP_KERNEL);
> +       if (!qp)
> +               return -ENOMEM;
> +
> +       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +       qp->base = devm_ioremap_resource(&pdev->dev, res);
> +       if (IS_ERR(qp->base))
> +               return PTR_ERR(qp->base);
> +
> +       qp->bus_clk = devm_clk_get(&pdev->dev, "bus_clk");
> +       if (IS_ERR(qp->bus_clk))
> +               return PTR_ERR(qp->bus_clk);
> +
> +       qp->bus_a_clk = devm_clk_get(&pdev->dev, "bus_a_clk");
> +       if (IS_ERR(qp->bus_a_clk))
> +               return PTR_ERR(qp->bus_a_clk);
> +
> +       provider = &qp->provider;
> +       provider->dev = &pdev->dev;
> +       provider->set = &qcom_icc_set;
> +       INIT_LIST_HEAD(&provider->nodes);
> +       provider->data = qp;
> +
> +       ret = icc_add_provider(provider);
> +       if (ret) {
> +               dev_err(&pdev->dev, "error adding interconnect
provider\n");
> +               return ret;
> +       }
> +
> +       for (i = 0; i < num_nodes; i++) {
> +               struct icc_node *node;
> +               int ret;
> +               size_t j;
> +
> +               node = icc_node_create(qnodes[i]->id);
> +               if (IS_ERR(node)) {
> +                       ret = PTR_ERR(node);
> +                       goto err;
> +               }
> +
> +               node->name = qnodes[i]->name;
> +               node->data = qnodes[i];
> +               icc_node_add(node, provider);
> +
> +               dev_dbg(&pdev->dev, "registered node %p %s %d\n", node,
> +                       qnodes[i]->name, node->id);
> +
> +               /* populate links */
> +               for (j = 0; j < qnodes[i]->num_links; j++)
> +                       if (qnodes[i]->links[j])
> +                               icc_link_create(node,
qnodes[i]->links[j]);
> +
> +               ret = qcom_icc_init(node);
> +               if (ret)
> +                       dev_err(&pdev->dev, "%s init error (%d)\n",
node->name,
> +                               ret);

Don't you want to call qcom_icc_init before icc_link_create? As soon as
icc_link_create is called, the node is connected to the graph, and
qcom_icc_set can be called.

> +       }
> +
> +       platform_set_drvdata(pdev, provider);
> +
> +       return ret;
> +err:
> +       icc_del_provider(provider);
> +       return ret;
> +}
> +
> +static int qnoc_remove(struct platform_device *pdev)
> +{
> +       struct icc_provider *provider = platform_get_drvdata(pdev);
> +
> +       icc_del_provider(provider);

Presumably in the framework nodes and links ought to get cleaned up
somewhere too, right? As it is now, the devm code frees provider when this
device is removed, even though provider is still very connected in the
graph via the nodes and links.

> +
> +       return 0;
> +}
> +
> +static const struct of_device_id qnoc_of_match[] = {
> +       { .compatible = "qcom,msm8916-pnoc", .data = &msm8916_pnoc },
> +       { .compatible = "qcom,msm8916-snoc", .data = &msm8916_snoc },
> +       { .compatible = "qcom,msm8916-bimc", .data = &msm8916_bimc },
> +       { },
> +};
> +MODULE_DEVICE_TABLE(of, qnoc_of_match);
> +
> +static struct platform_driver qnoc_driver = {
> +       .probe = qnoc_probe,
> +       .remove = qnoc_remove,
> +       .driver = {
> +               .name = "qnoc-msm8916",
> +               .of_match_table = qnoc_of_match,
> +       },
> +};
> +module_platform_driver(qnoc_driver);
> +MODULE_AUTHOR("Georgi Djakov <georgi.djakov@linaro.org>");
> +MODULE_DESCRIPTION("Qualcomm msm8916 NoC driver");
> +MODULE_LICENSE("GPL v2");
> diff --git a/include/linux/interconnect/qcom.h
b/include/linux/interconnect/qcom.h
> new file mode 100644
> index 000000000000..2cd378d2f575
> --- /dev/null
> +++ b/include/linux/interconnect/qcom.h
> @@ -0,0 +1,350 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Qualcomm interconnect IDs
> + *
> + * Copyright (c) 2018, Linaro Ltd.
> + * Author: Georgi Djakov <georgi.djakov@linaro.org>
> + */
> +
> +#ifndef __QCOM_INTERCONNECT_IDS_H
> +#define __QCOM_INTERCONNECT_IDS_H
> +
> +#define FAB_BIMC 0
> +#define FAB_SYS_NOC 1024
> +#define FAB_MMSS_NOC 2048
> +#define FAB_OCMEM_NOC 3072
> +#define FAB_PERIPH_NOC 4096
> +#define FAB_CONFIG_NOC 5120
> +#define FAB_OCMEM_VNOC 6144

Looks like you're still following that downstream convention of NoCs being
divisible by 1024, masters in 1-512, and slaves in 512-1023, then I don't
know about the 10000s. This was documented somewhere downstream, can you
add that documentation somewhere in here?

-Evan