i3c: mipi-i3c-hci: Use physical device pointer with DMA API

DMA transfer faults on Intel hardware when the IOMMU is enabled and
driver initialization will fail when attempting to do the first transfer:

	DMAR: DRHD: handling fault status reg 2
	DMAR: [DMA Read NO_PASID] Request device [00:11.0] fault addr 0x676e3000 [fault reason 0x71] SM: Present bit in first-level paging entry is clear
 	i3c mipi-i3c-hci.0: ring 0: Transfer Aborted
	mipi-i3c-hci mipi-i3c-hci.0: probe with driver mipi-i3c-hci failed with error -62

Reason for this is that the IOMMU setup is done for the physical devices
only and not for the virtual I3C Controller device object.

Therefore use the pointer to a physical device object with the DMA API.

Due to a data corruption observation when the device DMA is IOMMU
mapped, a properly sized receive bounce buffer is required if transfer
length is not a multiple of DWORDs.

Reported-by:
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20250822105630.2820009-4-jarkko.nikula@linux.intel.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

diff --git a/drivers/i3c/master/mipi-i3c-hci/dma.c b/drivers/i3c/master/mipi-i3c-hci/dma.c
index 351851859f02fe0146ced574ec4c63c8accd7d44..09688ada4912bfecbca5e0a8587675825a7e6da7 100644 (file)
--- a/drivers/i3c/master/mipi-i3c-hci/dma.c
+++ b/drivers/i3c/master/mipi-i3c-hci/dma.c
@@ -14,6 +14,7 @@
 #include <linux/errno.h>
 #include <linux/i3c/master.h>
 #include <linux/io.h>
+#include <linux/pci.h>
 
 #include "hci.h"
 #include "cmd.h"
@@ -138,6 +139,7 @@ struct hci_rh_data {
 };
 
 struct hci_rings_data {
+       struct device *sysdev;
        unsigned int total;
        struct hci_rh_data headers[] __counted_by(total);
 };
@@ -165,20 +167,20 @@ static void hci_dma_cleanup(struct i3c_hci *hci)
                rh_reg_write(IBI_SETUP, 0);
 
                if (rh->xfer)
-                       dma_free_coherent(&hci->master.dev,
+                       dma_free_coherent(rings->sysdev,
                                          rh->xfer_struct_sz * rh->xfer_entries,
                                          rh->xfer, rh->xfer_dma);
                if (rh->resp)
-                       dma_free_coherent(&hci->master.dev,
+                       dma_free_coherent(rings->sysdev,
                                          rh->resp_struct_sz * rh->xfer_entries,
                                          rh->resp, rh->resp_dma);
                kfree(rh->src_xfers);
                if (rh->ibi_status)
-                       dma_free_coherent(&hci->master.dev,
+                       dma_free_coherent(rings->sysdev,
                                          rh->ibi_status_sz * rh->ibi_status_entries,
                                          rh->ibi_status, rh->ibi_status_dma);
                if (rh->ibi_data_dma)
-                       dma_unmap_single(&hci->master.dev, rh->ibi_data_dma,
+                       dma_unmap_single(rings->sysdev, rh->ibi_data_dma,
                                         rh->ibi_chunk_sz * rh->ibi_chunks_total,
                                         DMA_FROM_DEVICE);
                kfree(rh->ibi_data);
@@ -194,11 +196,23 @@ static int hci_dma_init(struct i3c_hci *hci)
 {
        struct hci_rings_data *rings;
        struct hci_rh_data *rh;
+       struct device *sysdev;
        u32 regval;
        unsigned int i, nr_rings, xfers_sz, resps_sz;
        unsigned int ibi_status_ring_sz, ibi_data_ring_sz;
        int ret;
 
+       /*
+        * Set pointer to a physical device that does DMA and has IOMMU setup
+        * done for it in case of enabled IOMMU and use it with the DMA API.
+        * Here such device is either
+        * "mipi-i3c-hci" platform device (OF/ACPI enumeration) parent or
+        * grandparent (PCI enumeration).
+        */
+       sysdev = hci->master.dev.parent;
+       if (sysdev->parent && dev_is_pci(sysdev->parent))
+               sysdev = sysdev->parent;
+
        regval = rhs_reg_read(CONTROL);
        nr_rings = FIELD_GET(MAX_HEADER_COUNT_CAP, regval);
        dev_info(&hci->master.dev, "%d DMA rings available\n", nr_rings);
@@ -213,6 +227,7 @@ static int hci_dma_init(struct i3c_hci *hci)
                return -ENOMEM;
        hci->io_data = rings;
        rings->total = nr_rings;
+       rings->sysdev = sysdev;
 
        regval = FIELD_PREP(MAX_HEADER_COUNT, rings->total);
        rhs_reg_write(CONTROL, regval);
@@ -239,9 +254,9 @@ static int hci_dma_init(struct i3c_hci *hci)
                xfers_sz = rh->xfer_struct_sz * rh->xfer_entries;
                resps_sz = rh->resp_struct_sz * rh->xfer_entries;
 
-               rh->xfer = dma_alloc_coherent(&hci->master.dev, xfers_sz,
+               rh->xfer = dma_alloc_coherent(rings->sysdev, xfers_sz,
                                              &rh->xfer_dma, GFP_KERNEL);
-               rh->resp = dma_alloc_coherent(&hci->master.dev, resps_sz,
+               rh->resp = dma_alloc_coherent(rings->sysdev, resps_sz,
                                              &rh->resp_dma, GFP_KERNEL);
                rh->src_xfers =
                        kmalloc_array(rh->xfer_entries, sizeof(*rh->src_xfers),
@@ -295,16 +310,16 @@ static int hci_dma_init(struct i3c_hci *hci)
                ibi_data_ring_sz = rh->ibi_chunk_sz * rh->ibi_chunks_total;
 
                rh->ibi_status =
-                       dma_alloc_coherent(&hci->master.dev, ibi_status_ring_sz,
+                       dma_alloc_coherent(rings->sysdev, ibi_status_ring_sz,
                                           &rh->ibi_status_dma, GFP_KERNEL);
                rh->ibi_data = kmalloc(ibi_data_ring_sz, GFP_KERNEL);
                ret = -ENOMEM;
                if (!rh->ibi_status || !rh->ibi_data)
                        goto err_out;
                rh->ibi_data_dma =
-                       dma_map_single(&hci->master.dev, rh->ibi_data,
+                       dma_map_single(rings->sysdev, rh->ibi_data,
                                       ibi_data_ring_sz, DMA_FROM_DEVICE);
-               if (dma_mapping_error(&hci->master.dev, rh->ibi_data_dma)) {
+               if (dma_mapping_error(rings->sysdev, rh->ibi_data_dma)) {
                        rh->ibi_data_dma = 0;
                        ret = -ENOMEM;
                        goto err_out;
@@ -372,6 +387,7 @@ static int hci_dma_queue_xfer(struct i3c_hci *hci,
                u32 *ring_data = rh->xfer + rh->xfer_struct_sz * enqueue_ptr;
                enum dma_data_direction dir = xfer->rnw ? DMA_FROM_DEVICE :
                                                          DMA_TO_DEVICE;
+               bool need_bounce;
 
                /* store cmd descriptor */
                *ring_data++ = xfer->cmd_desc[0];
@@ -390,10 +406,13 @@ static int hci_dma_queue_xfer(struct i3c_hci *hci,
 
                /* 2nd and 3rd words of Data Buffer Descriptor Structure */
                if (xfer->data) {
-                       xfer->dma = i3c_master_dma_map_single(&hci->master.dev,
+                       need_bounce = device_iommu_mapped(rings->sysdev) &&
+                                     xfer->rnw &&
+                                     xfer->data_len != ALIGN(xfer->data_len, 4);
+                       xfer->dma = i3c_master_dma_map_single(rings->sysdev,
                                                              xfer->data,
                                                              xfer->data_len,
-                                                             false,
+                                                             need_bounce,
                                                              dir);
                        if (!xfer->dma) {
                                hci_dma_unmap_xfer(hci, xfer_list, i);
@@ -581,6 +600,7 @@ static void hci_dma_recycle_ibi_slot(struct i3c_hci *hci,
 
 static void hci_dma_process_ibi(struct i3c_hci *hci, struct hci_rh_data *rh)
 {
+       struct hci_rings_data *rings = hci->io_data;
        struct i3c_dev_desc *dev;
        struct i3c_hci_dev_data *dev_data;
        struct hci_dma_dev_ibi_data *dev_ibi;
@@ -691,7 +711,7 @@ static void hci_dma_process_ibi(struct i3c_hci *hci, struct hci_rh_data *rh)
                        * rh->ibi_chunk_sz;
        if (first_part > ibi_size)
                first_part = ibi_size;
-       dma_sync_single_for_cpu(&hci->master.dev, ring_ibi_data_dma,
+       dma_sync_single_for_cpu(rings->sysdev, ring_ibi_data_dma,
                                first_part, DMA_FROM_DEVICE);
        memcpy(slot->data, ring_ibi_data, first_part);
 
@@ -700,7 +720,7 @@ static void hci_dma_process_ibi(struct i3c_hci *hci, struct hci_rh_data *rh)
                /* we wrap back to the start and copy remaining data */
                ring_ibi_data = rh->ibi_data;
                ring_ibi_data_dma = rh->ibi_data_dma;
-               dma_sync_single_for_cpu(&hci->master.dev, ring_ibi_data_dma,
+               dma_sync_single_for_cpu(rings->sysdev, ring_ibi_data_dma,
                                        ibi_size - first_part, DMA_FROM_DEVICE);
                memcpy(slot->data + first_part, ring_ibi_data,
                       ibi_size - first_part);