[PATCH V2 09/10] i3c: mipi-i3c-hci-pci: Add support for Multi-Bus Instances
Frank Li
Frank.li at nxp.com
Fri Dec 12 09:46:28 PST 2025
On Fri, Dec 12, 2025 at 04:08:24PM +0200, Adrian Hunter wrote:
> On 11/12/2025 18:44, Frank Li wrote:
> > 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.
>
> Adding multiple instances is in a separate patch
Okay, commit message should mention it.
>
> >
> >> };
> >>
> >> +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.
>
> The ids have to be defined in any case.
>
> MFD still handles:
> Setting the firmware node
> Deleting devices if 1 fails to create
> Removing all devices i.e. mfd_remove_devices()
Actaully, why need remove previous failure device. assume support 15 device.
7 success. failure at 8 instance.
I think it'd better keep 7 already success devices. So 1-7 can work.
8-15 can't work.
It should be better than total 15 instances doesn't.
Frank
>
> >
> >> +}
> >> +
> >> 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
> >>
> >>
> >> --
> >> linux-i3c mailing list
> >> linux-i3c at lists.infradead.org
> >> http://lists.infradead.org/mailman/listinfo/linux-i3c
>
>
> --
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