Messages in this thread | | | Subject | Re: [PATCH] mmc: omap_hsmmc: fix initialization order of mmc block devices | From | Heiko Schocher <> | Date | Tue, 13 Oct 2015 09:44:19 +0200 |
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Hello Lokesh,
Am 13.10.2015 um 08:46 schrieb Lokesh Vutla: > +Nishanth, > > On Tuesday 13 October 2015 10:59 AM, Heiko Schocher wrote: >> On embedded devices, often there is a combination of >> removable mmc devices (e.g. MMC/SD cards) and hard >> wired ones (e.g. eMMC). Depending on the hardware >> configuration, the 'mmcblkN' node might change if >> the removable device is available or not at boot time. >> >> E.g. if the removable device is attached at boot time, >> it might become mmxblk0. And the hard wired one mmcblk1. >> But if the removable device isn't there at boot time, >> the hard wired one will become mmcblk0. This makes it >> somehow difficult to hard code the root device to the >> non-removable device and boot fast. > > Why not use "root=PARTUUID=${uuid}" option instead of relying on mmcblk no? > U-Boot can easily detect your partuuid. Refer to [1] on how TI platforms > does this in u-boot.
Good tip ... I do not know, if it is possible to update U-Boot on this boards...
Current U-Boot says: U-Boot 2013.01.01_heads/master-gc7900a0 (2015-05-06 - 20:37:15)
I2C: ready DRAM: 512 MiB [...] U-Boot# mmc rescan U-Boot# mmc part
Partition Map for MMC device 0 -- Partition Type: DOS
Part Start Sector Num Sectors UUID Type 1 63 144522 000ce343-01 0e Boot 2 144585 659861 000ce343-02 83 U-Boot# part uuid mmc 0:2 uuid Unknown command 'part' - try 'help' U-Boot#
So, if this patch has no chance for mainline, please let me know it, thanks!
bye, Heiko > > [1] > http://git.denx.de/?p=u-boot.git;a=commitdiff;h=437bc42e7ff930dc4d4bd47199d2e823cf84bf4c;hp=85d17be374678ec37fd1e55db994a942e400dc80 > > Thanks and regards, > Lokesh >> >> Signed-off-by: Heiko Schocher <hs@denx.de> >> --- >> Dirk Behme tried to bring this in, last mail I found: >> http://lists.infradead.org/pipermail/linux-arm-kernel/2012-July/111022.html >> where Dirk worked in Arnds suggestion to use the >> "/aliases" device node" >> >> I adapt this to the omap_hsmmc driver. >> >> Is there another solution for this problem? >> Or why was this patch not accepted to mainline? >> >> drivers/mmc/card/block.c | 6 ++++-- >> drivers/mmc/host/omap_hsmmc.c | 6 ++++++ >> include/linux/mmc/host.h | 3 +++ >> 3 files changed, 13 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c >> index c742cfd..62250d8 100644 >> --- a/drivers/mmc/card/block.c >> +++ b/drivers/mmc/card/block.c >> @@ -2106,7 +2106,8 @@ static struct mmc_blk_data *mmc_blk_alloc_req(struct mmc_card *card, >> struct mmc_blk_data *md; >> int devidx, ret; >> >> - devidx = find_first_zero_bit(dev_use, max_devices); >> + devidx = find_next_zero_bit(dev_use, max_devices, >> + card->host->devidx); >> if (devidx >= max_devices) >> return ERR_PTR(-ENOSPC); >> __set_bit(devidx, dev_use); >> @@ -2124,7 +2125,8 @@ static struct mmc_blk_data *mmc_blk_alloc_req(struct mmc_card *card, >> * index anymore so we keep track of a name index. >> */ >> if (!subname) { >> - md->name_idx = find_first_zero_bit(name_use, max_devices); >> + md->name_idx = find_next_zero_bit(name_use, max_devices, >> + card->host->devidx); >> __set_bit(md->name_idx, name_use); >> } else >> md->name_idx = ((struct mmc_blk_data *) >> diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c >> index 7fb0753..0b45b48 100644 >> --- a/drivers/mmc/host/omap_hsmmc.c >> +++ b/drivers/mmc/host/omap_hsmmc.c >> @@ -2059,6 +2059,12 @@ static int omap_hsmmc_probe(struct platform_device *pdev) >> host->pbias_enabled = 0; >> host->vqmmc_enabled = 0; >> >> + if (pdev->dev.of_node) { >> + ret = of_alias_get_id(pdev->dev.of_node, "mmcblk"); >> + if (ret >= 0) >> + host->mmc->devidx = ret; >> + } >> + >> ret = omap_hsmmc_gpio_init(mmc, host, pdata); >> if (ret) >> goto err_gpio; >> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h >> index 83b81fd..4f071681 100644 >> --- a/include/linux/mmc/host.h >> +++ b/include/linux/mmc/host.h >> @@ -382,6 +382,9 @@ struct mmc_host { >> int dsr_req; /* DSR value is valid */ >> u32 dsr; /* optional driver stage (DSR) value */ >> >> + /* preferred mmc block device index (mmcblkX) */ >> + unsigned int devidx; >> + >> unsigned long private[0] ____cacheline_aligned; >> }; >> >> >
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