On Fri, 2020-08-21 at 13:39 +0200, Ulf Hansson wrote: > On Thu, 20 Aug 2020 at 09:59, Matthias Schiffer > <matthias.schiffer@xxxxxxxxxxxxxxx> wrote: > > > > As with GPIO, UART and others, allow specifying the device index > > via the > > aliases node in the device tree. > > > > On embedded devices, there is often a combination of removable > > (e.g. > > SD card) and non-removable MMC devices (e.g. eMMC). > > Therefore the index might change depending on > > > > * host of removable device > > * removable card present or not > > > > This makes it difficult to hardcode the root device, if it is on > > the > > non-removable device. E.g. if SD card is present eMMC will be > > mmcblk1, > > if SD card is not present at boot, eMMC will be mmcblk0. > > Can you please add some information why Part-UUID/labels don't work > well to solve this problem on some embedded systems? > > I think that deserves to be in the changelog, after all the long > discussions we had in the history around this. Makes sense. I'll wait for your review before I send a v3 with an updated description. Matthias > > I will continue to review the code in a separate email, in a while. > > Kind regards > Uffe > > > > > All indices defined in the aliases node will be reserved for use by > > the > > respective MMC device, moving the indices of devices that don't > > have an > > alias up into the non-reserved range. If the aliases node is not > > found, > > the driver will act as before. > > > > This is a rebased and slightly cleaned up version of > > https://www.spinics.net/lists/linux-mmc/msg26588.html . > > > > Based-on-patch-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> > > Link: https://lkml.org/lkml/2020/8/5/194 > > Signed-off-by: Matthias Schiffer <matthias.schiffer@xxxxxxxxxxxxxxx > > > > > --- > > > > v2: fix missing symbols for modular mmcblock > > > > drivers/mmc/core/block.c | 13 +++++++++++-- > > drivers/mmc/core/core.c | 40 > > ++++++++++++++++++++++++++++++++++++++++ > > drivers/mmc/core/core.h | 3 +++ > > drivers/mmc/core/host.c | 15 +++++++++++++-- > > 4 files changed, 67 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c > > index 7896952de1ac..4620afaf0e50 100644 > > --- a/drivers/mmc/core/block.c > > +++ b/drivers/mmc/core/block.c > > @@ -38,6 +38,7 @@ > > #include <linux/pm_runtime.h> > > #include <linux/idr.h> > > #include <linux/debugfs.h> > > +#include <linux/of.h> > > > > #include <linux/mmc/ioctl.h> > > #include <linux/mmc/card.h> > > @@ -2260,9 +2261,17 @@ static struct mmc_blk_data > > *mmc_blk_alloc_req(struct mmc_card *card, > > int area_type) > > { > > struct mmc_blk_data *md; > > - int devidx, ret; > > + int rsvidx, devidx = -1, ret; > > + > > + rsvidx = mmc_get_reserved_index(card->host); > > + if (rsvidx >= 0) > > + devidx = ida_simple_get(&mmc_blk_ida, rsvidx, > > rsvidx + 1, > > + GFP_KERNEL); > > + if (devidx < 0) > > + devidx = ida_simple_get(&mmc_blk_ida, > > + mmc_first_nonreserved_index > > (), > > + max_devices, GFP_KERNEL); > > > > > > > - devidx = ida_simple_get(&mmc_blk_ida, 0, max_devices, > > GFP_KERNEL); > > if (devidx < 0) { > > /* > > * We get -ENOSPC because there are no more any > > available > > diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c > > index 8ccae6452b9c..5bce281a5faa 100644 > > --- a/drivers/mmc/core/core.c > > +++ b/drivers/mmc/core/core.c > > @@ -2419,10 +2419,50 @@ void mmc_unregister_pm_notifier(struct > > mmc_host *host) > > } > > #endif > > > > +static int mmc_max_reserved_idx = -1; > > + > > +/** > > + * mmc_first_nonreserved_index() - get the first index that is not > > reserved > > + */ > > +int mmc_first_nonreserved_index(void) > > +{ > > + return mmc_max_reserved_idx + 1; > > +} > > +EXPORT_SYMBOL(mmc_first_nonreserved_index); > > + > > +/** > > + * mmc_get_reserved_index() - get the index reserved for this MMC > > host > > + * > > + * Returns: > > + * The index reserved for this host on success, > > + * negative error if no index is reserved for this host > > + */ > > +int mmc_get_reserved_index(struct mmc_host *host) > > +{ > > + return of_alias_get_id(host->parent->of_node, "mmc"); > > +} > > +EXPORT_SYMBOL(mmc_get_reserved_index); > > + > > +static void __init mmc_of_reserve_idx(void) > > +{ > > + int max; > > + > > + max = of_alias_get_highest_id("mmc"); > > + if (max < 0) > > + return; > > + > > + mmc_max_reserved_idx = max; > > + > > + pr_debug("MMC: reserving %d slots for OF aliases\n", > > + mmc_max_reserved_idx + 1); > > +} > > + > > static int __init mmc_init(void) > > { > > int ret; > > > > + mmc_of_reserve_idx(); > > + > > ret = mmc_register_bus(); > > if (ret) > > return ret; > > diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h > > index 575ac0257af2..6aef6cf4e90f 100644 > > --- a/drivers/mmc/core/core.h > > +++ b/drivers/mmc/core/core.h > > @@ -79,6 +79,9 @@ int mmc_attach_mmc(struct mmc_host *host); > > int mmc_attach_sd(struct mmc_host *host); > > int mmc_attach_sdio(struct mmc_host *host); > > > > +int mmc_first_nonreserved_index(void); > > +int mmc_get_reserved_index(struct mmc_host *host); > > + > > /* Module parameters */ > > extern bool use_spi_crc; > > > > diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c > > index ce43f7573d80..386e15afde83 100644 > > --- a/drivers/mmc/core/host.c > > +++ b/drivers/mmc/core/host.c > > @@ -387,6 +387,7 @@ struct mmc_host *mmc_alloc_host(int extra, > > struct device *dev) > > { > > int err; > > struct mmc_host *host; > > + int alias_id, min_idx, max_idx; > > > > host = kzalloc(sizeof(struct mmc_host) + extra, > > GFP_KERNEL); > > if (!host) > > @@ -395,7 +396,18 @@ struct mmc_host *mmc_alloc_host(int extra, > > struct device *dev) > > /* scanning will be enabled when we're ready */ > > host->rescan_disable = 1; > > > > - err = ida_simple_get(&mmc_host_ida, 0, 0, GFP_KERNEL); > > + host->parent = dev; > > + > > + alias_id = mmc_get_reserved_index(host); > > + if (alias_id >= 0) { > > + min_idx = alias_id; > > + max_idx = alias_id + 1; > > + } else { > > + min_idx = mmc_first_nonreserved_index(); > > + max_idx = 0; > > + } > > + > > + err = ida_simple_get(&mmc_host_ida, min_idx, max_idx, > > GFP_KERNEL); > > if (err < 0) { > > kfree(host); > > return NULL; > > @@ -406,7 +418,6 @@ struct mmc_host *mmc_alloc_host(int extra, > > struct device *dev) > > dev_set_name(&host->class_dev, "mmc%d", host->index); > > host->ws = wakeup_source_register(NULL, dev_name(&host- > > >class_dev)); > > > > - host->parent = dev; > > host->class_dev.parent = dev; > > host->class_dev.class = &mmc_host_class; > > device_initialize(&host->class_dev); > > -- > > 2.17.1 > >
