Re: [PATCH V3 08/11] i3c: mipi-i3c-hci-pci: Pass base regs as platform data to i3c core device

Frank Li
2025-12-16T17:12:31Z

On Tue, Dec 16, 2025 at 06:56:39PM +0200, Adrian Hunter wrote:
> Use the parent's MMIO mapping for multi-bus instances to avoid overlapping
> regions. These instances share the same MMIO address space, but the ranges
> are not guaranteed to be contiguous. By passing base_regs from the parent
> mapping, child devices can access their registers without creating
> conflicting mappings.
>
> Prepare for multi-bus instance support by passing base_regs to child
> devices.
>
> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
> ---

Reviewed-by: Frank Li <Frank.Li@nxp.com>

>
>
> Changes in V3:
>
> Enhance commit message
>
> Changes in V2:
> New patch split from "i3c: mipi-i3c-hci-pci: Add support for
> Multi-Bus Instances"
>
>
> .../master/mipi-i3c-hci/mipi-i3c-hci-pci.c | 39 ++++++++++---------
> 1 file changed, 20 insertions(+), 19 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 3b319fbf18ce..ca562a5634e8 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
> @@ -14,12 +14,14 @@
> #include <linux/kernel.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>
>
> struct mipi_i3c_hci_pci {
> struct pci_dev *pci;
> struct platform_device *pdev;
> + void __iomem *base;
> const struct mipi_i3c_hci_pci_info *info;
> void *private;
> };
> @@ -32,7 +34,6 @@ struct mipi_i3c_hci_pci_info {
> };
>
> #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 +144,12 @@ 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;
>
> - if (!host || !priv)
> + if (!host)
> return -ENOMEM;
>
> dma_set_mask_and_coherent(&hci->pci->dev, DMA_BIT_MASK(64));
> @@ -196,8 +190,9 @@ static const struct mipi_i3c_hci_pci_info intel_2_info = {
> static int mipi_i3c_hci_pci_probe(struct pci_dev *pci,
> const struct pci_device_id *id)
> {
> + struct mipi_i3c_hci_platform_data pdata = {};
> struct mipi_i3c_hci_pci *hci;
> - struct resource res[2];
> + struct resource res;
> int ret;
>
> hci = devm_kzalloc(&pci->dev, sizeof(*hci), GFP_KERNEL);
> @@ -212,19 +207,19 @@ static int mipi_i3c_hci_pci_probe(struct pci_dev *pci,
>
> pci_set_master(pci);
>
> + hci->base = pcim_iomap_region(pci, 0, pci_name(pci));
> + if (IS_ERR(hci->base))
> + return PTR_ERR(hci->base);
> +
> ret = pci_alloc_irq_vectors(pci, 1, 1, PCI_IRQ_ALL_TYPES);
> if (ret < 0)
> return ret;
>
> 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_vector(hci->pci, 0);
> - res[1].end = res[1].start;
> + res.flags = IORESOURCE_IRQ;
> + res.start = pci_irq_vector(hci->pci, 0);
> + res.end = res.start;
>
> hci->info = (const struct mipi_i3c_hci_pci_info *)id->driver_data;
>
> @@ -235,7 +230,13 @@ static int mipi_i3c_hci_pci_probe(struct pci_dev *pci,
> hci->pdev->dev.parent = &pci->dev;
> device_set_node(&hci->pdev->dev, dev_fwnode(&pci->dev));
>
> - ret = platform_device_add_resources(hci->pdev, res, ARRAY_SIZE(res));
> + ret = platform_device_add_resources(hci->pdev, &res, 1);
> + if (ret)
> + goto err;
> +
> + pdata.base_regs = hci->base;
> +
> + ret = platform_device_add_data(hci->pdev, &pdata, sizeof(pdata));
> if (ret)
> goto err;
>
> --
> 2.51.0
>
>
> --
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