[PATCH v8 7/8] blkmap: add an attribute to preserve the mem mapping
Sughosh Ganu
sughosh.ganu at linaro.org
Thu Mar 13 08:37:47 CET 2025
On Thu, 13 Mar 2025 at 02:30, Heinrich Schuchardt
<heinrich.schuchardt at canonical.com> wrote:
>
> On 12.03.25 09:54, Sughosh Ganu wrote:
> > Some blkmap memory mapped devices might have to be relevant even after
> > U-Boot passes control to the next image as part of the platform
> > boot. An example of such a mapping would be an OS installer ISO image,
> > information for which has to be provided to the OS kernel. Use the
> > 'preserve' attribute for such mappings. The code for adding a pmem
> > node to the device-tree then checks if this attribute is set, and adds
> > a node only for mappings which have this attribute.
> >
> > Signed-off-by: Sughosh Ganu <sughosh.ganu at linaro.org>
> > Reviewed-by: Tobias Waldekranz <tobias at waldekranz.com>
> > Reviewed-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>
> > ---
> > Changes since V7:
> > * Fix repeated word in the commit message
> >
> > cmd/blkmap.c | 9 +++++++--
> > drivers/block/blkmap.c | 12 ++++++++----
> > drivers/block/blkmap_helper.c | 2 +-
> > include/blkmap.h | 4 +++-
> > 4 files changed, 19 insertions(+), 8 deletions(-)
> >
> > diff --git a/cmd/blkmap.c b/cmd/blkmap.c
> > index 164f80f1387..86a123b1cd3 100644
> > --- a/cmd/blkmap.c
> > +++ b/cmd/blkmap.c
> > @@ -62,13 +62,18 @@ static int do_blkmap_map_mem(struct map_ctx *ctx, int argc, char *const argv[])
> > {
> > phys_addr_t addr;
> > int err;
> > + bool preserve = false;
> >
> > if (argc < 2)
> > return CMD_RET_USAGE;
> >
> > addr = hextoul(argv[1], NULL);
> >
> > - err = blkmap_map_pmem(ctx->dev, ctx->blknr, ctx->blkcnt, addr);
> > + if (argc == 3 && !strcmp(argv[2], "preserve"))
> > + preserve = true;
> > +
> > + err = blkmap_map_pmem(ctx->dev, ctx->blknr, ctx->blkcnt, addr,
> > + preserve);
> > if (err) {
> > printf("Unable to map %#llx at block 0x" LBAF ": %d\n",
> > (unsigned long long)addr, ctx->blknr, err);
> > @@ -221,7 +226,7 @@ U_BOOT_CMD_WITH_SUBCMDS(
> > "blkmap create <label> - create device\n"
> > "blkmap destroy <label> - destroy device\n"
> > "blkmap map <label> <blk#> <cnt> linear <interface> <dev> <blk#> - device mapping\n"
> > - "blkmap map <label> <blk#> <cnt> mem <addr> - memory mapping\n",
> > + "blkmap map <label> <blk#> <cnt> mem <addr> [preserve] - memory mapping\n",
> > U_BOOT_SUBCMD_MKENT(info, 2, 1, do_blkmap_common),
> > U_BOOT_SUBCMD_MKENT(part, 2, 1, do_blkmap_common),
> > U_BOOT_SUBCMD_MKENT(dev, 4, 1, do_blkmap_common),
> > diff --git a/drivers/block/blkmap.c b/drivers/block/blkmap.c
> > index 453510cca62..eefed615998 100644
> > --- a/drivers/block/blkmap.c
> > +++ b/drivers/block/blkmap.c
> > @@ -19,6 +19,7 @@ struct blkmap;
> > /* Attributes of blkmap slice */
> > #define BLKMAP_SLICE_LINEAR BIT(0)
> > #define BLKMAP_SLICE_MEM BIT(1)
>
> Documentation is missing here.
Yeah you mentioned this in the earlier commit where this was added. I
will add the documentation for this.
-sughosh
>
> Cf.
> https://docs.kernel.org/doc-guide/kernel-doc.html#object-like-macro-documentation
>
> > +#define BLKMAP_SLICE_PRESERVE BIT(2)
> >
> > /**
> > * struct blkmap_slice - Region mapped to a blkmap
> > @@ -241,7 +242,7 @@ static void blkmap_mem_destroy(struct blkmap *bm, struct blkmap_slice *bms)
> > }
> >
> > int __blkmap_map_mem(struct udevice *dev, lbaint_t blknr, lbaint_t blkcnt,
> > - void *addr, bool remapped)
> > + void *addr, bool remapped, bool preserve)
> > {
> > struct blkmap *bm = dev_get_plat(dev);
> > struct blkmap_mem *bmm;
> > @@ -266,6 +267,9 @@ int __blkmap_map_mem(struct udevice *dev, lbaint_t blknr, lbaint_t blkcnt,
> > .remapped = remapped,
> > };
> >
> > + if (preserve)
> > + bmm->slice.attr |= BLKMAP_SLICE_PRESERVE;
> > +
> > err = blkmap_slice_add(bm, &bmm->slice);
> > if (err)
> > free(bmm);
> > @@ -276,11 +280,11 @@ int __blkmap_map_mem(struct udevice *dev, lbaint_t blknr, lbaint_t blkcnt,
> > int blkmap_map_mem(struct udevice *dev, lbaint_t blknr, lbaint_t blkcnt,
> > void *addr)
> > {
> > - return __blkmap_map_mem(dev, blknr, blkcnt, addr, false);
> > + return __blkmap_map_mem(dev, blknr, blkcnt, addr, false, false);
> > }
> >
> > int blkmap_map_pmem(struct udevice *dev, lbaint_t blknr, lbaint_t blkcnt,
> > - phys_addr_t paddr)
> > + phys_addr_t paddr, bool preserve)
> > {
> > struct blkmap *bm = dev_get_plat(dev);
> > struct blk_desc *bd = dev_get_uclass_plat(bm->blk);
> > @@ -291,7 +295,7 @@ int blkmap_map_pmem(struct udevice *dev, lbaint_t blknr, lbaint_t blkcnt,
> > if (!addr)
> > return -ENOMEM;
> >
> > - err = __blkmap_map_mem(dev, blknr, blkcnt, addr, true);
> > + err = __blkmap_map_mem(dev, blknr, blkcnt, addr, true, preserve);
> > if (err)
> > unmap_sysmem(addr);
> >
> > diff --git a/drivers/block/blkmap_helper.c b/drivers/block/blkmap_helper.c
> > index bfba14110d2..2f1bc28ee5d 100644
> > --- a/drivers/block/blkmap_helper.c
> > +++ b/drivers/block/blkmap_helper.c
> > @@ -28,7 +28,7 @@ int blkmap_create_ramdisk(const char *label, ulong image_addr, ulong image_size,
> > bm = dev_get_plat(bm_dev);
> > desc = dev_get_uclass_plat(bm->blk);
> > blknum = image_size >> desc->log2blksz;
> > - ret = blkmap_map_pmem(bm_dev, 0, blknum, image_addr);
> > + ret = blkmap_map_pmem(bm_dev, 0, blknum, image_addr, true);
> > if (ret) {
> > log_err("Unable to map %#llx at block %d : %d\n",
> > (unsigned long long)image_addr, 0, ret);
> > diff --git a/include/blkmap.h b/include/blkmap.h
> > index d53095437fa..754d8671b01 100644
> > --- a/include/blkmap.h
> > +++ b/include/blkmap.h
> > @@ -60,10 +60,12 @@ int blkmap_map_mem(struct udevice *dev, lbaint_t blknr, lbaint_t blkcnt,
> > * @blknr: Start block number of the mapping
> > * @blkcnt: Number of blocks to map
> > * @paddr: The target physical memory address of the mapping
> > + * @preserve: Mapping intended to be preserved for subsequent stages,
> > + * like the OS (e.g. ISO installer)
> > * Returns: 0 on success, negative error code on failure
> > */
> > int blkmap_map_pmem(struct udevice *dev, lbaint_t blknr, lbaint_t blkcnt,
> > - phys_addr_t paddr);
> > + phys_addr_t paddr, bool preserve);
> >
> > /**
> > * blkmap_from_label() - Find blkmap from label
>
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