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

Adrian Hunter
2025-12-16T16:57:09Z

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>
---

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;