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. > > 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); I am not sure why you need to change any of this. Currently we use the host->index, when creating the blockpartion name (dev.init_name). This is done for both rpmb and regular partitions. Isn't that sufficient? > 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); I think you can drop this function, just call of_alias_get_id() from where it's needed. > + > +static void __init mmc_of_reserve_idx(void) > +{ > + int max; > + > + max = of_alias_get_highest_id("mmc"); Is calling of_alias_get_highest_id("mmc") costly from an execution point of view? If not, we might as well call it directly from mmc_alloc_host() each time a host is allocated instead, to simplify the code a bit. > + if (max < 0) > + return; > + > + mmc_max_reserved_idx = max; > + > + pr_debug("MMC: reserving %d slots for OF aliases\n", > + mmc_max_reserved_idx + 1); If this function is needed at all (see comments above), then please drop this debug print. > +} > + > 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 > Kind regards Uffe
