Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted

Pull I3C updates from Alexandre Belloni:
 "A new driver this cycle, for the AMD AXI I3C controller.

  There are also new features such as IBI wakeup support, SETAASA device
  discovery and ACPI support for the the DAA methods, meaning we can now
  communicate with the SPD devices on DDR5 modules.

  New driver:
   - AMD AXI I3C master controller

  Subsystem:
   - I3C Common Command Code (CCC) handling improvements, especially
     around GET CCCs
   - SETAASA device discovery support
   - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as
     well as I2C devices on I3C bus
   - IBI-based wakeup support

  Drivers:
   - dw: SETAASA support
   - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C
     controller support, PIO queue management support for HCI v1.2
   - renesas: improve suspend to RAM support, add runtime PM support"

* tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits)
  i3c: dw: reduce do_daa time if there's no client
  i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller
  i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2
  i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode
  i3c: dw: rename "pclk" to "apb" to match dt-binding
  i3c: dw: make struct dw_i3c_cmd smaller
  i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding
  i3c: renesas: Don't register devices when ENTDAA times out
  i3c: master: dw-i3c-master: fix OD timing for first broadcast
  i3c: mipi-i3c-hci: Advertise IBI wakeup capability
  i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev()
  i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI
  i3c: master: Reject IBI requests from non-IBI-capable devices
  i3c: master: Add helper to query bus wakeup requirements
  i3c: master: Report wakeup events for IBIs
  i3c: master: Support IBI-based wakeup capability
  i3c: master: Fix potential UAF in i3c_device_match()
  i3c: master: Fix potential UAF in i3c_device_uevent()
  i3c: Make dev->desc locking assumptions explicit
  i3c: master: Fix use-after-free of master->this
  ...

1 files changed, 199 insertions, 0 deletions

diff --git a/lib/sg_split.c b/lib/sg_split.c
new file mode 100644
index 000000000..24e8f5e48
--- /dev/null
+++ b/lib/sg_split.c
@@ -0,0 +1,199 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2015 Robert Jarzmik <robert.jarzmik@free.fr>
+ *
+ * Scatterlist splitting helpers.
+ */
+
+#include <linux/scatterlist.h>
+#include <linux/slab.h>
+
+struct sg_splitter {
+	struct scatterlist *in_sg0;
+	int nents;
+	off_t skip_sg0;
+	unsigned int length_last_sg;
+
+	struct scatterlist *out_sg;
+};
+
+static int sg_calculate_split(struct scatterlist *in, int nents, int nb_splits,
+			      off_t skip, const size_t *sizes,
+			      struct sg_splitter *splitters, bool mapped)
+{
+	int i;
+	unsigned int sglen;
+	size_t size = sizes[0], len;
+	struct sg_splitter *curr = splitters;
+	struct scatterlist *sg;
+
+	for (i = 0; i < nb_splits; i++) {
+		splitters[i].in_sg0 = NULL;
+		splitters[i].nents = 0;
+	}
+
+	for_each_sg(in, sg, nents, i) {
+		sglen = mapped ? sg_dma_len(sg) : sg->length;
+		if (skip > sglen) {
+			skip -= sglen;
+			continue;
+		}
+
+		len = min_t(size_t, size, sglen - skip);
+		if (!curr->in_sg0) {
+			curr->in_sg0 = sg;
+			curr->skip_sg0 = skip;
+		}
+		size -= len;
+		curr->nents++;
+		curr->length_last_sg = len;
+
+		while (!size && (skip + len < sglen) && (--nb_splits > 0)) {
+			curr++;
+			size = *(++sizes);
+			skip += len;
+			len = min_t(size_t, size, sglen - skip);
+
+			curr->in_sg0 = sg;
+			curr->skip_sg0 = skip;
+			curr->nents = 1;
+			curr->length_last_sg = len;
+			size -= len;
+		}
+		skip = 0;
+
+		if (!size && --nb_splits > 0) {
+			curr++;
+			size = *(++sizes);
+		}
+
+		if (!nb_splits)
+			break;
+	}
+
+	return (size || !splitters[0].in_sg0) ? -EINVAL : 0;
+}
+
+static void sg_split_phys(struct sg_splitter *splitters, const int nb_splits)
+{
+	int i, j;
+	struct scatterlist *in_sg, *out_sg;
+	struct sg_splitter *split;
+
+	for (i = 0, split = splitters; i < nb_splits; i++, split++) {
+		in_sg = split->in_sg0;
+		out_sg = split->out_sg;
+		for (j = 0; j < split->nents; j++, out_sg++) {
+			*out_sg = *in_sg;
+			if (!j) {
+				out_sg->offset += split->skip_sg0;
+				out_sg->length -= split->skip_sg0;
+			}
+			sg_dma_address(out_sg) = 0;
+			sg_dma_len(out_sg) = 0;
+			in_sg = sg_next(in_sg);
+		}
+		out_sg[-1].length = split->length_last_sg;
+		sg_mark_end(out_sg - 1);
+	}
+}
+
+static void sg_split_mapped(struct sg_splitter *splitters, const int nb_splits)
+{
+	int i, j;
+	struct scatterlist *in_sg, *out_sg;
+	struct sg_splitter *split;
+
+	for (i = 0, split = splitters; i < nb_splits; i++, split++) {
+		in_sg = split->in_sg0;
+		out_sg = split->out_sg;
+		for (j = 0; j < split->nents; j++, out_sg++) {
+			sg_dma_address(out_sg) = sg_dma_address(in_sg);
+			sg_dma_len(out_sg) = sg_dma_len(in_sg);
+			if (!j) {
+				sg_dma_address(out_sg) += split->skip_sg0;
+				sg_dma_len(out_sg) -= split->skip_sg0;
+			}
+			in_sg = sg_next(in_sg);
+		}
+		sg_dma_len(--out_sg) = split->length_last_sg;
+	}
+}
+
+/**
+ * sg_split - split a scatterlist into several scatterlists
+ * @in: the input sg list
+ * @in_mapped_nents: the result of a dma_map_sg(in, ...), or 0 if not mapped.
+ * @skip: the number of bytes to skip in the input sg list
+ * @nb_splits: the number of desired sg outputs
+ * @split_sizes: the respective size of each output sg list in bytes
+ * @out: an array where to store the allocated output sg lists
+ * @out_mapped_nents: the resulting sg lists mapped number of sg entries. Might
+ *                    be NULL if sglist not already mapped (in_mapped_nents = 0)
+ * @gfp_mask: the allocation flag
+ *
+ * This function splits the input sg list into nb_splits sg lists, which are
+ * allocated and stored into out.
+ * The @in is split into :
+ *  - @out[0], which covers bytes [@skip .. @skip + @split_sizes[0] - 1] of @in
+ *  - @out[1], which covers bytes [@skip + split_sizes[0] ..
+ *                                 @skip + @split_sizes[0] + @split_sizes[1] -1]
+ * etc ...
+ * It will be the caller's duty to kfree() out array members.
+ *
+ * Returns 0 upon success, or error code
+ */
+int sg_split(struct scatterlist *in, const int in_mapped_nents,
+	     const off_t skip, const int nb_splits,
+	     const size_t *split_sizes,
+	     struct scatterlist **out, int *out_mapped_nents,
+	     gfp_t gfp_mask)
+{
+	int i, ret;
+	struct sg_splitter *splitters;
+
+	splitters = kzalloc_objs(*splitters, nb_splits, gfp_mask);
+	if (!splitters)
+		return -ENOMEM;
+
+	ret = sg_calculate_split(in, sg_nents(in), nb_splits, skip, split_sizes,
+			   splitters, false);
+	if (ret < 0)
+		goto err;
+
+	ret = -ENOMEM;
+	for (i = 0; i < nb_splits; i++) {
+		splitters[i].out_sg = kmalloc_objs(struct scatterlist,
+						   splitters[i].nents, gfp_mask);
+		if (!splitters[i].out_sg)
+			goto err;
+	}
+
+	/*
+	 * The order of these 3 calls is important and should be kept.
+	 */
+	sg_split_phys(splitters, nb_splits);
+	if (in_mapped_nents) {
+		ret = sg_calculate_split(in, in_mapped_nents, nb_splits, skip,
+					 split_sizes, splitters, true);
+		if (ret < 0)
+			goto err;
+		sg_split_mapped(splitters, nb_splits);
+	}
+
+	for (i = 0; i < nb_splits; i++) {
+		out[i] = splitters[i].out_sg;
+		if (out_mapped_nents)
+			out_mapped_nents[i] = splitters[i].nents;
+	}
+
+	kfree(splitters);
+	return 0;
+
+err:
+	for (i = 0; i < nb_splits; i++)
+		kfree(splitters[i].out_sg);
+	kfree(splitters);
+	return ret;
+}
+EXPORT_SYMBOL(sg_split);