[PATCH V2 09/10] i3c: mipi-i3c-hci-pci: Add support for Multi-Bus Instances
Frank Li
Frank.li at nxp.com
Thu Dec 11 08:44:28 PST 2025
On Thu, Dec 11, 2025 at 03:48:08PM +0200, Adrian Hunter wrote:
> A MIPI I3C Host Controller with the Multi-Bus Instance capability supports
> multiple I3C Buses (up to 15).
with single hardware function (e.g. PCIe B/D/F).
...
> 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).
Each I3C bus have indepedent HCI register space and I3C Bus controller logic.
>
> Create an MFD cell 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>
> ---
>
>
> Changes in V2:
> Conversion to MFD split into separate patch
> Simplify ID allocation / free
> Correct use of __free()
> Also define instance 0 in driver_data
>
>
> .../master/mipi-i3c-hci/mipi-i3c-hci-pci.c | 63 +++++++++++++++----
> 1 file changed, 50 insertions(+), 13 deletions(-)
>
> 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 68088967942b..de1f71763786 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
> @@ -19,10 +19,17 @@
> #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 {
> struct pci_dev *pci;
> void __iomem *base;
> - int dev_id;
> + int dev_id[INST_MAX];
> + int dev_id_cnt;
> const struct mipi_i3c_hci_pci_info *info;
> void *private;
> };
> @@ -30,6 +37,8 @@ struct mipi_i3c_hci_pci {
> struct mipi_i3c_hci_pci_info {
> int (*init)(struct mipi_i3c_hci_pci *hci);
> void (*exit)(struct mipi_i3c_hci_pci *hci);
> + u32 instance_offset[INST_MAX];
> + int instance_count;
> };
>
> static DEFINE_IDA(mipi_i3c_hci_pci_ida);
> @@ -177,53 +186,81 @@ static void intel_i3c_exit(struct mipi_i3c_hci_pci *hci)
> static const struct mipi_i3c_hci_pci_info intel_info = {
> .init = intel_i3c_init,
> .exit = intel_i3c_exit,
> + .instance_offset = {0},
> + .instance_count = 1,
just one instance? suppose at least 2, otherwise, not need this patch.
> };
>
> +static void mipi_i3c_hci_pci_free_ids(struct mipi_i3c_hci_pci *hci)
> +{
> + for (int i = 0; i < hci->dev_id_cnt; i++)
> + ida_free(&mipi_i3c_hci_pci_ida, hci->dev_id[i]);
> +}
> +
> +static int mipi_i3c_hci_pci_alloc_ids(struct mipi_i3c_hci_pci *hci, int nr)
> +{
> + for (int i = 0; i < nr; i++) {
> + hci->dev_id[i] = ida_alloc(&mipi_i3c_hci_pci_ida, GFP_KERNEL);
> + if (hci->dev_id[i] < 0)
> + goto err_free_ids;
> + hci->dev_id_cnt = i + 1;
> + }
> +
> + return 0;
> +
> +err_free_ids:
> + mipi_i3c_hci_pci_free_ids(hci);
> + return -ENOMEM;
You have to handle ida error, actually, it makes not big difference with
mfd and add multi platform devices.
> +}
> +
> 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,
> +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)
> {
> - data->pdata.base_regs = hci->base;
> + data->pdata.base_regs = hci->base + hci->info->instance_offset[idx];
>
> data->res = DEFINE_RES_IRQ(0);
>
> cell->name = "mipi-i3c-hci";
> - cell->id = hci->dev_id;
> + cell->id = hci->dev_id[idx];
> cell->platform_data = &data->pdata;
> cell->pdata_size = sizeof(data->pdata);
> cell->num_resources = 1;
> cell->resources = &data->res;
> }
>
> +#define mipi_i3c_hci_pci_alloc(x) kcalloc(hci->info->instance_count, sizeof(*(x)), GFP_KERNEL)
> +
It is not good to hide hci in macro.
mipi_i3c_hci_pci_alloc(hci, x); or
mipi_i3c_hci_pci_alloc(nr, x)
> static int mipi_i3c_hci_pci_add_instances(struct mipi_i3c_hci_pci *hci)
> {
> - struct mipi_i3c_hci_pci_cell_data *data __free(kfree) = kzalloc(sizeof(*data), GFP_KERNEL);
> - struct mfd_cell *cells __free(kfree) = kzalloc(sizeof(*cells), GFP_KERNEL);
> + struct mipi_i3c_hci_pci_cell_data *data __free(kfree) = mipi_i3c_hci_pci_alloc(data);
> + struct mfd_cell *cells __free(kfree) = mipi_i3c_hci_pci_alloc(cells);
> int irq = pci_irq_vector(hci->pci, 0);
> + int nr = hci->info->instance_count;
> int ret;
>
> if (!cells || !data)
> return -ENOMEM;
>
> - hci->dev_id = ida_alloc(&mipi_i3c_hci_pci_ida, GFP_KERNEL);
> - if (hci->dev_id < 0)
> - return hci->dev_id;
> + ret = mipi_i3c_hci_pci_alloc_ids(hci, nr);
> + if (ret)
> + return ret;
>
> - mipi_i3c_hci_pci_setup_cell(hci, data, cells);
> + for (int i = 0; i < nr; i++)
> + mipi_i3c_hci_pci_setup_cell(hci, i, data + i, cells + i);
>
> - ret = mfd_add_devices(&hci->pci->dev, 0, cells, 1, NULL, irq, NULL);
> + ret = mfd_add_devices(&hci->pci->dev, 0, cells, nr, NULL, irq, NULL);
> if (ret)
> goto err_free_ids;
>
> return 0;
>
> err_free_ids:
> - ida_free(&mipi_i3c_hci_pci_ida, hci->dev_id);
> + mipi_i3c_hci_pci_free_ids(hci);
> return ret;
> }
>
> @@ -281,7 +318,7 @@ static void mipi_i3c_hci_pci_remove(struct pci_dev *pci)
> hci->info->exit(hci);
>
> mfd_remove_devices(&pci->dev);
> - ida_free(&mipi_i3c_hci_pci_ida, hci->dev_id);
> + 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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