On Fri, May 19, 2023 at 08:12:15PM +0530, Manivannan Sadhasivam wrote:
> Add PCI Endpoint driver for the Qualcomm MHI (Modem Host Interface) bus.
> The driver implements the MHI function over PCI in the endpoint device
> such as SDX55 modem. The MHI endpoint function driver acts as a
> controller driver for the MHI Endpoint stack and carries out all PCI
> related activities like mapping the host memory using iATU, triggering
> MSIs etc...
>
> Reviewed-by: Kishon Vijay Abraham I <kishon@xxxxxxxxxx>
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
> ---
> drivers/pci/endpoint/functions/Kconfig | 10 +
> drivers/pci/endpoint/functions/Makefile | 1 +
> drivers/pci/endpoint/functions/pci-epf-mhi.c | 454 +++++++++++++++++++
> 3 files changed, 465 insertions(+)
> create mode 100644 drivers/pci/endpoint/functions/pci-epf-mhi.c
>
> diff --git a/drivers/pci/endpoint/functions/Kconfig b/drivers/pci/endpoint/functions/Kconfig
> index 9fd560886871..f5171b4fabbe 100644
> --- a/drivers/pci/endpoint/functions/Kconfig
> +++ b/drivers/pci/endpoint/functions/Kconfig
> @@ -37,3 +37,13 @@ config PCI_EPF_VNTB
> between PCI Root Port and PCIe Endpoint.
>
> If in doubt, say "N" to disable Endpoint NTB driver.
> +
> +config PCI_EPF_MHI
> + tristate "PCI Endpoint driver for MHI bus"
> + depends on PCI_ENDPOINT && MHI_BUS_EP
> + help
> + Enable this configuration option to enable the PCI Endpoint
> + driver for Modem Host Interface (MHI) bus in Qualcomm Endpoint
> + devices such as SDX55.
> +
> + If in doubt, say "N" to disable Endpoint driver for MHI bus.
> diff --git a/drivers/pci/endpoint/functions/Makefile b/drivers/pci/endpoint/functions/Makefile
> index 5c13001deaba..696473fce50e 100644
> --- a/drivers/pci/endpoint/functions/Makefile
> +++ b/drivers/pci/endpoint/functions/Makefile
> @@ -6,3 +6,4 @@
> obj-$(CONFIG_PCI_EPF_TEST) += pci-epf-test.o
> obj-$(CONFIG_PCI_EPF_NTB) += pci-epf-ntb.o
> obj-$(CONFIG_PCI_EPF_VNTB) += pci-epf-vntb.o
> +obj-$(CONFIG_PCI_EPF_MHI) += pci-epf-mhi.o
> diff --git a/drivers/pci/endpoint/functions/pci-epf-mhi.c b/drivers/pci/endpoint/functions/pci-epf-mhi.c
> new file mode 100644
> index 000000000000..df924fb10e4d
> --- /dev/null
> +++ b/drivers/pci/endpoint/functions/pci-epf-mhi.c
> @@ -0,0 +1,454 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * PCI EPF driver for MHI Endpoint devices
> + *
> + * Copyright (C) 2022 Linaro Ltd.
> + * Author: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
> + */
> +
> +#include <linux/mhi_ep.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/pci-epc.h>
> +#include <linux/pci-epf.h>
> +
> +#define MHI_VERSION_1_0 0x01000000
> +
> +struct pci_epf_mhi_ep_info {
> + const struct mhi_ep_cntrl_config *config;
> + struct pci_epf_header *epf_header;
> + enum pci_barno bar_num;
> + u32 epf_flags;
> + u32 msi_count;
> + u32 mru;
> +};
> +
> +#define MHI_EP_CHANNEL_CONFIG_UL(ch_num, ch_name) \
> + { \
> + .num = ch_num, \
> + .name = ch_name, \
> + .dir = DMA_TO_DEVICE, \
> + }
> +
> +#define MHI_EP_CHANNEL_CONFIG_DL(ch_num, ch_name) \
> + { \
> + .num = ch_num, \
> + .name = ch_name, \
> + .dir = DMA_FROM_DEVICE, \
> + }
You can define it as:
#define MHI_EP_CHANNEL_CONFIG(ch_num, ch_name, dir) \
{ \
.num = ch_num, \
.name = ch_name, \
.dir = dir, \
}
#define MHI_EP_CHANNEL_CONFIG_DL(ch_num, ch_name) \
MHI_EP_CHANNEL_CONFIG(ch_num, ch_name, DMA_FROM_DEVICE)
etc.
> +
> +static const struct mhi_ep_channel_config mhi_v1_channels[] = {
> + MHI_EP_CHANNEL_CONFIG_UL(0, "LOOPBACK"),
> + MHI_EP_CHANNEL_CONFIG_DL(1, "LOOPBACK"),
> + MHI_EP_CHANNEL_CONFIG_UL(2, "SAHARA"),
> + MHI_EP_CHANNEL_CONFIG_DL(3, "SAHARA"),
> + MHI_EP_CHANNEL_CONFIG_UL(4, "DIAG"),
> + MHI_EP_CHANNEL_CONFIG_DL(5, "DIAG"),
> + MHI_EP_CHANNEL_CONFIG_UL(6, "SSR"),
> + MHI_EP_CHANNEL_CONFIG_DL(7, "SSR"),
> + MHI_EP_CHANNEL_CONFIG_UL(8, "QDSS"),
> + MHI_EP_CHANNEL_CONFIG_DL(9, "QDSS"),
> + MHI_EP_CHANNEL_CONFIG_UL(10, "EFS"),
> + MHI_EP_CHANNEL_CONFIG_DL(11, "EFS"),
> + MHI_EP_CHANNEL_CONFIG_UL(12, "MBIM"),
> + MHI_EP_CHANNEL_CONFIG_DL(13, "MBIM"),
> + MHI_EP_CHANNEL_CONFIG_UL(14, "QMI"),
> + MHI_EP_CHANNEL_CONFIG_DL(15, "QMI"),
> + MHI_EP_CHANNEL_CONFIG_UL(16, "QMI"),
> + MHI_EP_CHANNEL_CONFIG_DL(17, "QMI"),
> + MHI_EP_CHANNEL_CONFIG_UL(18, "IP-CTRL-1"),
> + MHI_EP_CHANNEL_CONFIG_DL(19, "IP-CTRL-1"),
> + MHI_EP_CHANNEL_CONFIG_UL(20, "IPCR"),
> + MHI_EP_CHANNEL_CONFIG_DL(21, "IPCR"),
> + MHI_EP_CHANNEL_CONFIG_UL(32, "DUN"),
> + MHI_EP_CHANNEL_CONFIG_DL(33, "DUN"),
> + MHI_EP_CHANNEL_CONFIG_UL(46, "IP_SW0"),
> + MHI_EP_CHANNEL_CONFIG_DL(47, "IP_SW0"),
> +};
> +
> +static const struct mhi_ep_cntrl_config mhi_v1_config = {
> + .max_channels = 128,
> + .num_channels = ARRAY_SIZE(mhi_v1_channels),
> + .ch_cfg = mhi_v1_channels,
> + .mhi_version = MHI_VERSION_1_0,
> +};
> +
> +static struct pci_epf_header sdx55_header = {
> + .vendorid = PCI_VENDOR_ID_QCOM,
> + .deviceid = 0x0306,
> + .baseclass_code = PCI_BASE_CLASS_COMMUNICATION,
> + .subclass_code = PCI_CLASS_COMMUNICATION_MODEM & 0xff,
> + .interrupt_pin = PCI_INTERRUPT_INTA,
> +};
> +
> +static const struct pci_epf_mhi_ep_info sdx55_info = {
> + .config = &mhi_v1_config,
> + .epf_header = &sdx55_header,
> + .bar_num = BAR_0,
> + .epf_flags = PCI_BASE_ADDRESS_MEM_TYPE_32,
> + .msi_count = 32,
> + .mru = 0x8000,
> +};
> +
> +struct pci_epf_mhi {
> + const struct pci_epf_mhi_ep_info *info;
> + struct mhi_ep_cntrl mhi_cntrl;
> + struct pci_epf *epf;
> + struct mutex lock;
> + void __iomem *mmio;
> + resource_size_t mmio_phys;
> + u32 mmio_size;
> + int irq;
> + bool mhi_registered;
Do we really need this variable ? Can't it be inferred from
the framework ?
> +};
> +
> +static int pci_epf_mhi_alloc_map(struct mhi_ep_cntrl *mhi_cntrl, u64 pci_addr,
> + phys_addr_t *phys_ptr, void __iomem **virt, size_t size)
> +{
> + struct pci_epf_mhi *epf_mhi = container_of(mhi_cntrl, struct pci_epf_mhi, mhi_cntrl);
> + struct pci_epf *epf = epf_mhi->epf;
> + struct pci_epc *epc = epf_mhi->epf->epc;
> + size_t offset = pci_addr & (epc->mem->window.page_size - 1);
> + void __iomem *virt_addr;
> + phys_addr_t phys_addr;
> + int ret;
> +
> + virt_addr = pci_epc_mem_alloc_addr(epc, &phys_addr, size + offset);
> + if (!virt_addr)
> + return -ENOMEM;
> +
> + ret = pci_epc_map_addr(epc, epf->func_no, epf->vfunc_no, phys_addr, pci_addr - offset,
> + size + offset);
> + if (ret) {
> + pci_epc_mem_free_addr(epc, phys_addr, virt_addr, size + offset);
> +
> + return ret;
> + }
> +
> + *phys_ptr = phys_addr + offset;
> + *virt = virt_addr + offset;
> +
> + return 0;
> +}
> +
> +static void pci_epf_mhi_unmap_free(struct mhi_ep_cntrl *mhi_cntrl, u64 pci_addr,
> + phys_addr_t phys_addr, void __iomem *virt_addr, size_t size)
> +{
> + struct pci_epf_mhi *epf_mhi = container_of(mhi_cntrl, struct pci_epf_mhi, mhi_cntrl);
> + struct pci_epf *epf = epf_mhi->epf;
> + struct pci_epc *epc = epf->epc;
> + size_t offset = pci_addr & (epc->mem->window.page_size - 1);
> +
> + pci_epc_unmap_addr(epc, epf->func_no, epf->vfunc_no, phys_addr - offset);
> + pci_epc_mem_free_addr(epc, phys_addr - offset, virt_addr - offset, size + offset);
> +}
> +
> +static void pci_epf_mhi_raise_irq(struct mhi_ep_cntrl *mhi_cntrl, u32 vector)
> +{
> + struct pci_epf_mhi *epf_mhi = container_of(mhi_cntrl, struct pci_epf_mhi, mhi_cntrl);
> + struct pci_epf *epf = epf_mhi->epf;
> + struct pci_epc *epc = epf->epc;
> +
> + /*
> + * Vector is incremented by 1 here as the DWC core will decrement it before
> + * writing to iATU.
This isn't OK. It is an API, you can't write code explicitly relying on
the underlying implementation. I assume the API is not well specified,
that's why we need these tricks ?
> + */
> + pci_epc_raise_irq(epc, epf->func_no, epf->vfunc_no, PCI_EPC_IRQ_MSI, vector + 1);
> +}
> +
> +static int pci_epf_mhi_read_from_host(struct mhi_ep_cntrl *mhi_cntrl, u64 from, void __iomem *to,
> + size_t size)
> +{
> + struct pci_epf_mhi *epf_mhi = container_of(mhi_cntrl, struct pci_epf_mhi, mhi_cntrl);
> + struct pci_epf *epf = epf_mhi->epf;
> + struct pci_epc *epc = epf_mhi->epf->epc;
> + void __iomem *tre_buf;
> + phys_addr_t tre_phys;
> + size_t offset = from % 0x1000;
Explain what 0x1000 represents - make it a macro if that
helps
> + int ret;
> +
> + mutex_lock(&epf_mhi->lock);
> +
> + tre_buf = pci_epc_mem_alloc_addr(epc, &tre_phys, size + offset);
> + if (!tre_buf) {
> + mutex_unlock(&epf_mhi->lock);
> + return -ENOMEM;
> + }
> +
> + ret = pci_epc_map_addr(epc, epf->func_no, epf->vfunc_no, tre_phys, from - offset,
> + size + offset);
> + if (ret) {
> + pci_epc_mem_free_addr(epc, tre_phys, tre_buf, size + offset);
> + mutex_unlock(&epf_mhi->lock);
I'd prefer a single goto label instead of repeating the code for every
branch taken but that's up to you.
> + return ret;
> + }
> +
> + memcpy_fromio(to, tre_buf + offset, size);
> +
> + pci_epc_unmap_addr(epc, epf->func_no, epf->vfunc_no, tre_phys);
> + pci_epc_mem_free_addr(epc, tre_phys, tre_buf, size + offset);
> +
> + mutex_unlock(&epf_mhi->lock);
> +
> + return 0;
> +}
> +
> +static int pci_epf_mhi_write_to_host(struct mhi_ep_cntrl *mhi_cntrl, void __iomem *from, u64 to,
> + size_t size)
> +{
> + struct pci_epf_mhi *epf_mhi = container_of(mhi_cntrl, struct pci_epf_mhi, mhi_cntrl);
> + struct pci_epf *epf = epf_mhi->epf;
> + struct pci_epc *epc = epf_mhi->epf->epc;
> + void __iomem *tre_buf;
> + phys_addr_t tre_phys;
> + size_t offset = to % 0x1000;
Ditto as above.
> + int ret;
> +
> + mutex_lock(&epf_mhi->lock);
> +
> + tre_buf = pci_epc_mem_alloc_addr(epc, &tre_phys, size + offset);
> + if (!tre_buf) {
> + mutex_unlock(&epf_mhi->lock);
> + return -ENOMEM;
> + }
> +
> + ret = pci_epc_map_addr(epc, epf->func_no, epf->vfunc_no, tre_phys, to - offset,
> + size + offset);
> + if (ret) {
> + pci_epc_mem_free_addr(epc, tre_phys, tre_buf, size + offset);
> + mutex_unlock(&epf_mhi->lock);
Ditto.
> + return ret;
> + }
> +
> + memcpy_toio(tre_buf + offset, from, size);
> +
> + pci_epc_unmap_addr(epc, epf->func_no, epf->vfunc_no, tre_phys);
> + pci_epc_mem_free_addr(epc, tre_phys, tre_buf, size + offset);
> +
> + mutex_unlock(&epf_mhi->lock);
> +
> + return 0;
> +}
> +
> +static int pci_epf_mhi_core_init(struct pci_epf *epf)
> +{
> + struct pci_epf_mhi *epf_mhi = epf_get_drvdata(epf);
> + const struct pci_epf_mhi_ep_info *info = epf_mhi->info;
> + struct pci_epf_bar *epf_bar = &epf->bar[info->bar_num];
> + struct pci_epc *epc = epf->epc;
> + struct device *dev = &epf->dev;
> + int ret;
> +
> + epf_bar->phys_addr = epf_mhi->mmio_phys;
> + epf_bar->size = epf_mhi->mmio_size;
> + epf_bar->barno = info->bar_num;
> + epf_bar->flags = info->epf_flags;
> + ret = pci_epc_set_bar(epc, epf->func_no, epf->vfunc_no, epf_bar);
> + if (ret) {
> + dev_err(dev, "Failed to set BAR: %d\n", ret);
> + return ret;
> + }
> +
> + ret = pci_epc_set_msi(epc, epf->func_no, epf->vfunc_no,
> + order_base_2(info->msi_count));
> + if (ret) {
> + dev_err(dev, "Failed to set MSI configuration: %d\n", ret);
> + return ret;
> + }
> +
> + ret = pci_epc_write_header(epc, epf->func_no, epf->vfunc_no, epf->header);
> + if (ret) {
> + dev_err(dev, "Failed to set Configuration header: %d\n", ret);
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static int pci_epf_mhi_link_up(struct pci_epf *epf)
> +{
> + struct pci_epf_mhi *epf_mhi = epf_get_drvdata(epf);
> + const struct pci_epf_mhi_ep_info *info = epf_mhi->info;
> + struct mhi_ep_cntrl *mhi_cntrl = &epf_mhi->mhi_cntrl;
> + struct pci_epc *epc = epf->epc;
> + struct device *dev = &epf->dev;
> + int ret;
> +
> + mhi_cntrl->mmio = epf_mhi->mmio;
> + mhi_cntrl->irq = epf_mhi->irq;
> + mhi_cntrl->mru = info->mru;
> +
> + /* Assign the struct dev of PCI EP as MHI controller device */
> + mhi_cntrl->cntrl_dev = epc->dev.parent;
> + mhi_cntrl->raise_irq = pci_epf_mhi_raise_irq;
> + mhi_cntrl->alloc_map = pci_epf_mhi_alloc_map;
> + mhi_cntrl->unmap_free = pci_epf_mhi_unmap_free;
> + mhi_cntrl->read_from_host = pci_epf_mhi_read_from_host;
> + mhi_cntrl->write_to_host = pci_epf_mhi_write_to_host;
> +
> + /* Register the MHI EP controller */
> + ret = mhi_ep_register_controller(mhi_cntrl, info->config);
> + if (ret) {
> + dev_err(dev, "Failed to register MHI EP controller: %d\n", ret);
> + return ret;
> + }
> +
> + epf_mhi->mhi_registered = true;
I don't like this. It should be part of mhi_ep_register_controller();
> +
> + return 0;
> +}
> +
> +static int pci_epf_mhi_link_down(struct pci_epf *epf)
> +{
> + struct pci_epf_mhi *epf_mhi = epf_get_drvdata(epf);
> + struct mhi_ep_cntrl *mhi_cntrl = &epf_mhi->mhi_cntrl;
> +
> + if (epf_mhi->mhi_registered) {
> + mhi_ep_power_down(mhi_cntrl);
> + mhi_ep_unregister_controller(mhi_cntrl);
> + epf_mhi->mhi_registered = false;
> + }
> +
> + return 0;
> +}
> +
> +static int pci_epf_mhi_bme(struct pci_epf *epf)
> +{
> + struct pci_epf_mhi *epf_mhi = epf_get_drvdata(epf);
> + struct mhi_ep_cntrl *mhi_cntrl = &epf_mhi->mhi_cntrl;
> + struct device *dev = &epf->dev;
> + int ret;
> +
> + /* Power up the MHI EP stack if link is up and stack is in power down state */
> + if (!mhi_cntrl->enabled && epf_mhi->mhi_registered) {
> + ret = mhi_ep_power_up(mhi_cntrl);
> + if (ret) {
> + dev_err(dev, "Failed to power up MHI EP: %d\n", ret);
> + mhi_ep_unregister_controller(mhi_cntrl);
> + epf_mhi->mhi_registered = false;
> + }
> + }
> +
> + return 0;
> +}
> +
> +static int pci_epf_mhi_bind(struct pci_epf *epf)
> +{
> + struct pci_epf_mhi *epf_mhi = epf_get_drvdata(epf);
> + struct pci_epc *epc = epf->epc;
> + struct platform_device *pdev = to_platform_device(epc->dev.parent);
> + struct device *dev = &epf->dev;
> + struct resource *res;
> + int ret;
> +
> + if (WARN_ON_ONCE(!epc))
> + return -EINVAL;
> +
> + /* Get MMIO base address from Endpoint controller */
> + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "mmio");
> + epf_mhi->mmio_phys = res->start;
> + epf_mhi->mmio_size = resource_size(res);
> +
> + epf_mhi->mmio = ioremap_wc(epf_mhi->mmio_phys, epf_mhi->mmio_size);
ioremap_wc(). Why wc mappings ? Please explain.
Thanks,
Lorenzo
> + if (IS_ERR(epf_mhi->mmio))
> + return PTR_ERR(epf_mhi->mmio);
> +
> + ret = platform_get_irq_byname(pdev, "doorbell");
> + if (ret < 0) {
> + dev_err(dev, "Failed to get Doorbell IRQ\n");
> + iounmap(epf_mhi->mmio);
> + return ret;
> + }
> +
> + epf_mhi->irq = ret;
> +
> + return 0;
> +}
> +
> +static void pci_epf_mhi_unbind(struct pci_epf *epf)
> +{
> + struct pci_epf_mhi *epf_mhi = epf_get_drvdata(epf);
> + const struct pci_epf_mhi_ep_info *info = epf_mhi->info;
> + struct pci_epf_bar *epf_bar = &epf->bar[info->bar_num];
> + struct mhi_ep_cntrl *mhi_cntrl = &epf_mhi->mhi_cntrl;
> + struct pci_epc *epc = epf->epc;
> +
> + /*
> + * Forcefully power down the MHI EP stack. Only way to bring the MHI EP stack
> + * back to working state after successive bind is by getting BME from host.
> + */
> + if (epf_mhi->mhi_registered) {
> + mhi_ep_power_down(mhi_cntrl);
> + mhi_ep_unregister_controller(mhi_cntrl);
> + epf_mhi->mhi_registered = false;
> + }
> +
> + iounmap(epf_mhi->mmio);
> + pci_epc_clear_bar(epc, epf->func_no, epf->vfunc_no, epf_bar);
> +}
> +
> +static struct pci_epc_event_ops pci_epf_mhi_event_ops = {
> + .core_init = pci_epf_mhi_core_init,
> + .link_up = pci_epf_mhi_link_up,
> + .link_down = pci_epf_mhi_link_down,
> + .bme = pci_epf_mhi_bme,
> +};
> +
> +static int pci_epf_mhi_probe(struct pci_epf *epf, const struct pci_epf_device_id *id)
> +{
> + struct pci_epf_mhi_ep_info *info = (struct pci_epf_mhi_ep_info *) id->driver_data;
> + struct pci_epf_mhi *epf_mhi;
> + struct device *dev = &epf->dev;
> +
> + epf_mhi = devm_kzalloc(dev, sizeof(*epf_mhi), GFP_KERNEL);
> + if (!epf_mhi)
> + return -ENOMEM;
> +
> + epf->header = info->epf_header;
> + epf_mhi->info = info;
> + epf_mhi->epf = epf;
> +
> + epf->event_ops = &pci_epf_mhi_event_ops;
> +
> + mutex_init(&epf_mhi->lock);
> +
> + epf_set_drvdata(epf, epf_mhi);
> +
> + return 0;
> +}
> +
> +static const struct pci_epf_device_id pci_epf_mhi_ids[] = {
> + {
> + .name = "sdx55", .driver_data = (kernel_ulong_t) &sdx55_info,
> + },
> + {},
> +};
> +
> +static struct pci_epf_ops pci_epf_mhi_ops = {
> + .unbind = pci_epf_mhi_unbind,
> + .bind = pci_epf_mhi_bind,
> +};
> +
> +static struct pci_epf_driver pci_epf_mhi_driver = {
> + .driver.name = "pci_epf_mhi",
> + .probe = pci_epf_mhi_probe,
> + .id_table = pci_epf_mhi_ids,
> + .ops = &pci_epf_mhi_ops,
> + .owner = THIS_MODULE,
> +};
> +
> +static int __init pci_epf_mhi_init(void)
> +{
> + return pci_epf_register_driver(&pci_epf_mhi_driver);
> +}
> +module_init(pci_epf_mhi_init);
> +
> +static void __exit pci_epf_mhi_exit(void)
> +{
> + pci_epf_unregister_driver(&pci_epf_mhi_driver);
> +}
> +module_exit(pci_epf_mhi_exit);
> +
> +MODULE_DESCRIPTION("PCI EPF driver for MHI Endpoint devices");
> +MODULE_AUTHOR("Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>");
> +MODULE_LICENSE("GPL");
> --
> 2.25.1
>
