[PATCH 6/7] i3c: mipi-i3c-hci-pci: Add support for Multi-Bus Instances
Frank Li
Frank.li at nxp.com
Tue Dec 9 09:10:43 PST 2025
On Tue, Dec 09, 2025 at 01:51:03PM +0200, Adrian Hunter wrote:
> A MIPI I3C Host Controller with the Multi-Bus Instance capability supports
> multiple I3C Buses (up to 15), with one instance of the HCI Register Set
> and one instance of I3C Bus Controller Logic for each I3C Bus, in a single
> hardware function (e.g. PCIe B/D/F).
>
> Convert to a Multifunction driver and create an MFD cell for each instance.
> Create a separate platform device for each instance. Use platform_data to
> pass the instance's register set start address.
>
> MIPI I3C specification defines an Extended Capability to hold the offset
> of each instance register set. However parsing to find that information is
> relatively complicated compared with just including it in the driver data.
> Do that for now.
>
> Signed-off-by: Adrian Hunter <adrian.hunter at intel.com>
> ---
> drivers/i3c/master/Kconfig | 1 +
> .../master/mipi-i3c-hci/mipi-i3c-hci-pci.c | 180 +++++++++++++-----
> 2 files changed, 131 insertions(+), 50 deletions(-)
>
> diff --git a/drivers/i3c/master/Kconfig b/drivers/i3c/master/Kconfig
> index 82cf330778d5..2609f2b18e0a 100644
> --- a/drivers/i3c/master/Kconfig
> +++ b/drivers/i3c/master/Kconfig
> @@ -69,6 +69,7 @@ config MIPI_I3C_HCI_PCI
> tristate "MIPI I3C Host Controller Interface PCI support"
> depends on MIPI_I3C_HCI
> depends on PCI
> + select MFD_CORE
> help
> Support for MIPI I3C Host Controller Interface compatible hardware
> on the PCI bus.
> diff --git a/drivers/i3c/master/mipi-i3c-hci/mipi-i3c-hci-pci.c b/drivers/i3c/master/mipi-i3c-hci/mipi-i3c-hci-pci.c
> index ccaec5d3d248..145f9adadf75 100644
> --- a/drivers/i3c/master/mipi-i3c-hci/mipi-i3c-hci-pci.c
> +++ b/drivers/i3c/master/mipi-i3c-hci/mipi-i3c-hci-pci.c
> @@ -12,27 +12,43 @@
> #include <linux/idr.h>
> #include <linux/iopoll.h>
> #include <linux/kernel.h>
> +#include <linux/mfd/core.h>
> #include <linux/module.h>
> #include <linux/pci.h>
> +#include <linux/platform_data/mipi-i3c-hci.h>
> #include <linux/platform_device.h>
> #include <linux/pm_qos.h>
>
> +/*
> + * There can up to 15 instances, but implementations have at most 2 at this
> + * time.
> + */
> +#define INST_MAX 2
> +
> +struct mipi_i3c_hci_pci_instance {
> + int dev_id;
> + u32 offset;
> +};
> +
> struct mipi_i3c_hci_pci {
> struct pci_dev *pci;
> - struct platform_device *pdev;
> + void __iomem *base;
> const struct mipi_i3c_hci_pci_info *info;
> + struct mipi_i3c_hci_pci_instance instances[INST_MAX];
> void *private;
> };
>
> struct mipi_i3c_hci_pci_info {
> + struct mipi_i3c_hci_platform_data pdata;
> int (*init)(struct mipi_i3c_hci_pci *hci);
> void (*exit)(struct mipi_i3c_hci_pci *hci);
> + u32 instance_offset[INST_MAX - 1]; /* Excludes instance at offset 0 */
what difference with mipi_i3c_hci_pci_instance: offset?
> + int instance_count;
> };
>
> static DEFINE_IDA(mipi_i3c_hci_pci_ida);
>
> #define INTEL_PRIV_OFFSET 0x2b0
> -#define INTEL_PRIV_SIZE 0x28
> #define INTEL_RESETS 0x04
> #define INTEL_RESETS_RESET BIT(0)
> #define INTEL_RESETS_RESET_DONE BIT(1)
> @@ -143,19 +159,12 @@ static void intel_reset(void __iomem *priv)
> writel(INTEL_RESETS_RESET, priv + INTEL_RESETS);
> }
>
> -static void __iomem *intel_priv(struct pci_dev *pci)
> -{
> - resource_size_t base = pci_resource_start(pci, 0);
> -
> - return devm_ioremap(&pci->dev, base + INTEL_PRIV_OFFSET, INTEL_PRIV_SIZE);
> -}
> -
> static int intel_i3c_init(struct mipi_i3c_hci_pci *hci)
> {
> struct intel_host *host = devm_kzalloc(&hci->pci->dev, sizeof(*host), GFP_KERNEL);
> - void __iomem *priv = intel_priv(hci->pci);
> + void __iomem *priv = hci->base + INTEL_PRIV_OFFSET;
Does need lock if mult instance to access this MMIO space? Especial enable
disable irq, which generally use read modify write pattern.
>
> - if (!host || !priv)
> + if (!host)
> return -ENOMEM;
>
> dma_set_mask_and_coherent(&hci->pci->dev, DMA_BIT_MASK(64));
> @@ -187,12 +196,106 @@ static const struct mipi_i3c_hci_pci_info intel_info = {
> static const struct mipi_i3c_hci_pci_info dflt_info = {
> };
>
> +static void mipi_i3c_hci_pci_init_ids(struct mipi_i3c_hci_pci *hci)
> +{
> + /* 0 is a valid id, so set unallocated ids to -1 */
> + for (int i = 0; i < INST_MAX; i++)
> + hci->instances[i].dev_id = -1;
> +}
> +
> +static void mipi_i3c_hci_pci_free_ids(struct mipi_i3c_hci_pci *hci)
> +{
> + /* ida_free() ignores negative ids */
> + for (int i = 0; i < INST_MAX; i++)
> + ida_free(&mipi_i3c_hci_pci_ida, hci->instances[i].dev_id);
> +
> + mipi_i3c_hci_pci_init_ids(hci);
> +}
> +
> +static int mipi_i3c_hci_pci_alloc_ids(struct mipi_i3c_hci_pci *hci, int nr)
> +{
> + int dev_id;
> +
> + mipi_i3c_hci_pci_init_ids(hci);
> +
> + for (int i = 0; i < nr; i++) {
> + dev_id = ida_alloc(&mipi_i3c_hci_pci_ida, GFP_KERNEL);
> + if (dev_id < 0)
> + goto err_free_ids;
> + hci->instances[i].dev_id = dev_id;
> + }
> +
> + return 0;
> +
> +err_free_ids:
> + mipi_i3c_hci_pci_free_ids(hci);
> + return -ENOMEM;
> +}
Feel like above logic have some complex, add nr in mipi_i3c_hci_pci.
INST_MAX can be 15.
mipi_i3c_hci_pci_free_ids(hci)
{
for (int i = 0; i < hci->nr; i++)
ida_free(&mipi_i3c_hci_pci_ida, hci->instances[i].dev_id);
}
mipi_i3c_hci_pci_alloc_ids(hci, nr)
{
for (int i = 0; i < nr; i++) {
dev_id = ida_alloc(&mipi_i3c_hci_pci_ida, GFP_KERNEL);
if (dev_id) < 0)
goto err_free_ids;
hci->nr = i;
}
return 0;
err_free_ids:
mipi_i3c_hci_pci_free_ids(hci)
return --ENOMEM;
}
> +
> +struct mipi_i3c_hci_pci_cell_data {
> + struct mipi_i3c_hci_platform_data pdata;
> + struct resource res;
> +};
> +
> +static void mipi_i3c_hci_pci_setup_cell(struct mipi_i3c_hci_pci *hci, int idx,
> + struct mipi_i3c_hci_pci_cell_data *data,
> + struct mfd_cell *cell)
> +{
> + u32 offset = idx ? hci->info->instance_offset[idx - 1] : 0;
When idx is 1, copy from instance_offset[0] ?
when idx is 0, offset is 0, so hci->instances[0].offset = offset;
so hci->instances[0].offset is 0.
then hci->instances[1].offset will be 0?
> +
> + hci->instances[idx].offset = offset;
> +
> + data->pdata = hci->info->pdata;
> + data->pdata.base_regs = hci->base + offset;
> +
> + data->res = DEFINE_RES_IRQ(0);
> +
> + cell->name = "mipi-i3c-hci";
> + cell->id = hci->instances[idx].dev_id;
> + cell->platform_data = &data->pdata;
> + cell->pdata_size = sizeof(data->pdata);
> + cell->num_resources = 1;
> + cell->resources = &data->res;
> +}
> +
> +static int mipi_i3c_hci_pci_add_instances(struct mipi_i3c_hci_pci *hci)
> +{
> + int instance_count = hci->info->instance_count + 1; /* Include instance at offset 0 */
> + struct mipi_i3c_hci_pci_cell_data *data __free(kfree);
now prefer assign value when declear, see cleanup.h
struct mipi_i3c_hci_pci_cell_data *data __free(kfree) =
kcalloc(instance_count, sizeof(*data), GFP_KERNEL);
> + struct mfd_cell *cells __free(kfree);
> + int irq;
> + int ret;
> +
> + cells = kcalloc(instance_count, sizeof(*cells), GFP_KERNEL);
> + data = kcalloc(instance_count, sizeof(*data), GFP_KERNEL);
> + if (!cells || !data)
> + return -ENOMEM;
> +
> + ret = mipi_i3c_hci_pci_alloc_ids(hci, instance_count);
> + if (ret)
> + return ret;
> +
> + for (int i = 0; i < instance_count; i++)
> + mipi_i3c_hci_pci_setup_cell(hci, i, data + i, cells + i);
> +
> + irq = pci_irq_vector(hci->pci, 0);
> +
> + ret = mfd_add_devices(&hci->pci->dev, 0, cells, instance_count, NULL, irq, NULL);
> + if (ret)
> + goto err_free_ids;
> +
> + return 0;
> +
> +err_free_ids:
> + mipi_i3c_hci_pci_free_ids(hci);
> + return ret;
> +}
> +
> static int mipi_i3c_hci_pci_probe(struct pci_dev *pci,
> const struct pci_device_id *id)
> {
> struct mipi_i3c_hci_pci *hci;
> - struct resource res[2];
> - int dev_id, ret;
> + int ret;
>
> hci = devm_kzalloc(&pci->dev, sizeof(*hci), GFP_KERNEL);
> if (!hci)
> @@ -204,68 +307,45 @@ static int mipi_i3c_hci_pci_probe(struct pci_dev *pci,
> if (ret)
> return ret;
>
> - pci_set_master(pci);
> -
> - memset(&res, 0, sizeof(res));
> -
> - res[0].flags = IORESOURCE_MEM;
> - res[0].start = pci_resource_start(pci, 0);
> - res[0].end = pci_resource_end(pci, 0);
> -
> - res[1].flags = IORESOURCE_IRQ;
> - res[1].start = pci->irq;
> - res[1].end = pci->irq;
> + ret = pci_alloc_irq_vectors(pci, 1, 1, PCI_IRQ_ALL_TYPES);
> + if (ret < 0)
> + return ret;
>
> - dev_id = ida_alloc(&mipi_i3c_hci_pci_ida, GFP_KERNEL);
> - if (dev_id < 0)
> - return dev_id;
> + pci_set_master(pci);
>
> - hci->pdev = platform_device_alloc("mipi-i3c-hci", dev_id);
> - if (!hci->pdev)
> - return -ENOMEM;
> + hci->base = pcim_iomap_region(pci, 0, pci_name(pci));
> + if (IS_ERR(hci->base))
> + return PTR_ERR(hci->base);
>
> - hci->pdev->dev.parent = &pci->dev;
> - device_set_node(&hci->pdev->dev, dev_fwnode(&pci->dev));
> + hci->info = (const struct mipi_i3c_hci_pci_info *)id->driver_data ?: &dflt_info;
>
> - ret = platform_device_add_resources(hci->pdev, res, ARRAY_SIZE(res));
> + ret = hci->info->init ? hci->info->init(hci) : 0;
> if (ret)
> - goto err;
> + return ret;
>
> - hci->info = (const struct mipi_i3c_hci_pci_info *)id->driver_data ?: &dflt_info;
> - if (hci->info->init) {
> - ret = hci->info->init(hci);
> - if (ret)
> - goto err;
> - }
> + pci_set_drvdata(pci, hci);
>
> - ret = platform_device_add(hci->pdev);
> + ret = mipi_i3c_hci_pci_add_instances(hci);
> if (ret)
> goto err_exit;
>
> - pci_set_drvdata(pci, hci);
> -
Is it simple if
for (int i = 0; i < nr; i++)
platform_device_register_data(hci->pdev, data, ..., i);
Generally, mfd is used for difference kind devices. Do you know any exiting
code use for create multi instance?
Frank
> return 0;
>
> err_exit:
> if (hci->info->exit)
> hci->info->exit(hci);
> -err:
> - platform_device_put(hci->pdev);
> - ida_free(&mipi_i3c_hci_pci_ida, dev_id);
> return ret;
> }
>
> static void mipi_i3c_hci_pci_remove(struct pci_dev *pci)
> {
> struct mipi_i3c_hci_pci *hci = pci_get_drvdata(pci);
> - struct platform_device *pdev = hci->pdev;
> - int dev_id = pdev->id;
>
> if (hci->info->exit)
> hci->info->exit(hci);
>
> - platform_device_unregister(pdev);
> - ida_free(&mipi_i3c_hci_pci_ida, dev_id);
> + mfd_remove_devices(&pci->dev);
> + mipi_i3c_hci_pci_free_ids(hci);
> }
>
> static const struct pci_device_id mipi_i3c_hci_pci_devices[] = {
> --
> 2.51.0
>
>
> --
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