mmc0 on Nokia N900 on Linux 5.4.18

mmc0 on Nokia N900 on Linux 5.4.18

[Merlijn Wajer]

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Hi,

When booting Linux 5.4.18 with omap2plus_defconfig, I no longer get a
/dev/mmcblk0 device - the one corresponding to my microSD card, where
u-boot also loads the kernel from.

This also likely seems to be a regression, but I haven't tried to hunt
it down yet.

Kernel log attached, below.

Cheers,
Merlijn


[    0.000000] Booting Linux on physical CPU 0x0
[    0.000000] Linux version 5.4.18 (merlijn@kgpe-d16) (gcc version
7.3.0 (Gentoo Hardened 7.3.0-r3 p1.4)) #5 SMP Fri Feb 7 17:43:53 CET 2020
[    0.000000] CPU: ARMv7 Processor [411fc083] revision 3 (ARMv7),
cr=10c5387d
[    0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT nonaliasing
instruction cache
[    0.000000] OF: fdt: Machine model: Nokia N900
[    0.000000] Malformed early option 'earlycon'
[    0.000000] Memory policy: Data cache writeback
[    0.000000] cma: Reserved 16 MiB at 0x8e800000
[    0.000000] On node 0 totalpages: 65024
[    0.000000]   Normal zone: 572 pages used for memmap
[    0.000000]   Normal zone: 0 pages reserved
[    0.000000]   Normal zone: 65024 pages, LIFO batch:15
[    0.000000] CPU: All CPU(s) started in SVC mode.
[    0.000000] OMAP3430/3530 ES3.1 (l2cache iva sgx neon isp)
[    0.000000] percpu: Embedded 19 pages/cpu s48780 r8192 d20852 u77824
[    0.000000] pcpu-alloc: s48780 r8192 d20852 u77824 alloc=19*4096
[    0.000000] pcpu-alloc: [0] 0
[    0.000000] Built 1 zonelists, mobility grouping on.  Total pages: 64452
[    0.000000] Kernel command line: console=tty0 console=ttyS2,115200
debug earlycon ro rootwait rootfstype=ext4 root=/dev/mmcblk0p2 init=/bin/sh
[    0.000000] Dentry cache hash table entries: 32768 (order: 5, 131072
bytes, linear)
[    0.000000] Inode-cache hash table entries: 16384 (order: 4, 65536
bytes, linear)
[    0.000000] mem auto-init: stack:off, heap alloc:off, heap free:off
[    0.000000] Memory: 228556K/260096K available (7168K kernel code,
713K rwdata, 2076K rodata, 1024K init, 258K bss, 15156K reserved, 16384K
cma-reserved, 0K highmem)
[    0.000000] rcu: Hierarchical RCU implementation.
[    0.000000] rcu:     RCU event tracing is enabled.
[    0.000000] rcu:     RCU restricting CPUs from NR_CPUS=2 to nr_cpu_ids=1.
[    0.000000] rcu: RCU calculated value of scheduler-enlistment delay
is 10 jiffies.
[    0.000000] rcu: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=1
[    0.000000] NR_IRQS: 16, nr_irqs: 16, preallocated irqs: 16
[    0.000000] IRQ: Found an INTC at 0x(ptrval) (revision 4.0) with 96
interrupts
[    0.000000] random: get_random_bytes called from
start_kernel+0x2b0/0x4e0 with crng_init=0
[    0.000000] Clocking rate (Crystal/Core/MPU): 19.2/332/500 MHz
[    0.000000] OMAP clockevent source: timer1 at 32768 Hz
[    0.000000] clocksource: 32k_counter: mask: 0xffffffff max_cycles:
0xffffffff, max_idle_ns: 58327039986419 ns
[    0.000000] sched_clock: 32 bits at 32kHz, resolution 30517ns, wraps
every 65535999984741ns
[    0.000030] OMAP clocksource: 32k_counter at 32768 Hz
[    0.001770] Console: colour dummy device 80x30
[    0.002624] printk: console [tty0] enabled
[    0.002716] Calibrating delay loop... 496.43 BogoMIPS (lpj=2482176)
[    0.047424] pid_max: default: 32768 minimum: 301
[    0.047790] LSM: Security Framework initializing
[    0.048034] Mount-cache hash table entries: 1024 (order: 0, 4096
bytes, linear)
[    0.048126] Mountpoint-cache hash table entries: 1024 (order: 0, 4096
bytes, linear)
[    0.050384] CPU: Testing write buffer coherency: ok
[    0.050567] CPU0: Spectre v2: using BPIALL workaround
[    0.051361] CPU0: thread -1, cpu 0, socket -1, mpidr 0
[    0.053344] Setting up static identity map for 0x80100000 - 0x80100078
[    0.053802] rcu: Hierarchical SRCU implementation.
[    0.054809] smp: Bringing up secondary CPUs ...
[    0.054870] smp: Brought up 1 node, 1 CPU
[    0.054901] SMP: Total of 1 processors activated (496.43 BogoMIPS).
[    0.054931] CPU: All CPU(s) started in SVC mode.
[    0.056121] devtmpfs: initialized
[    0.101867] VFP support v0.3: implementor 41 architecture 3 part 30
variant c rev 1
[    0.102600] clocksource: jiffies: mask: 0xffffffff max_cycles:
0xffffffff, max_idle_ns: 19112604462750000 ns
[    0.102691] futex hash table entries: 256 (order: 2, 16384 bytes, linear)
[    0.105102] pinctrl core: initialized pinctrl subsystem
[    0.108276] NET: Registered protocol family 16
[    0.114807] DMA: preallocated 256 KiB pool for atomic coherent
allocations
[    0.155059] omap_hwmod: mcbsp2_sidetone using broken dt data from mcbsp
[    0.156311] omap_hwmod: mcbsp3_sidetone using broken dt data from mcbsp
[    0.219299] audit: initializing netlink subsys (disabled)
[    0.221618] cpuidle: using governor menu
[    0.222442] Reprogramming SDRC clock to 332000000 Hz
[    0.231689] audit: type=2000 audit(0.220:1): state=initialized
audit_enabled=0 res=1
[    0.232086] gpio gpiochip0: (gpio-0-31): added GPIO chardev (254:0)
[    0.232330] gpiochip_setup_dev: registered GPIOs 0 to 31 on device:
gpiochip0 (gpio-0-31)
[    0.232452] OMAP GPIO hardware version 2.5
[    0.234222] gpio gpiochip1: (gpio-32-63): added GPIO chardev (254:1)
[    0.234497] gpiochip_setup_dev: registered GPIOs 32 to 63 on device:
gpiochip1 (gpio-32-63)
[    0.236236] gpio gpiochip2: (gpio-64-95): added GPIO chardev (254:2)
[    0.236480] gpiochip_setup_dev: registered GPIOs 64 to 95 on device:
gpiochip2 (gpio-64-95)
[    0.238403] gpio gpiochip3: (gpio-96-127): added GPIO chardev (254:3)
[    0.238647] gpiochip_setup_dev: registered GPIOs 96 to 127 on device:
gpiochip3 (gpio-96-127)
[    0.240417] gpio gpiochip4: (gpio-128-159): added GPIO chardev (254:4)
[    0.240661] gpiochip_setup_dev: registered GPIOs 128 to 159 on
device: gpiochip4 (gpio-128-159)
[    0.242401] gpio gpiochip5: (gpio-160-191): added GPIO chardev (254:5)
[    0.242645] gpiochip_setup_dev: registered GPIOs 160 to 191 on
device: gpiochip5 (gpio-160-191)
[    0.268585] RX-51: Enabling ARM errata 430973 workaround
[    0.270782] hw-breakpoint: debug architecture 0x4 unsupported.
[    0.273437] Reserving DMA channels 0 and 1 for HS ROM code
[    0.273498] OMAP DMA hardware revision 4.0
[    0.331756] omap-dma-engine 48056000.dma-controller: OMAP DMA engine
driver
[    0.337768] iommu: Default domain type: Translated
[    0.340576] omap-iommu 480bd400.mmu: 480bd400.mmu registered
[    0.341461] platform 480bc000.isp: Adding to iommu group 0
[    0.345245] vgaarb: loaded
[    0.346405] SCSI subsystem initialized
[    0.347534] libata version 3.00 loaded.
[    0.348907] pps_core: LinuxPPS API ver. 1 registered
[    0.348937] pps_core: Software ver. 5.3.6 - Copyright 2005-2007
Rodolfo Giometti <giometti@linux.it>
[    0.349060] PTP clock support registered
[    0.351226] clocksource: Switched to clocksource 32k_counter
[    1.465576] VFS: Disk quotas dquot_6.6.0
[    1.465850] VFS: Dquot-cache hash table entries: 1024 (order 0, 4096
bytes)
[    1.490692] thermal_sys: Registered thermal governor 'fair_share'
[    1.490692] thermal_sys: Registered thermal governor 'step_wise'
[    1.490783] thermal_sys: Registered thermal governor 'user_space'
[    1.492431] NET: Registered protocol family 2
[    1.494049] tcp_listen_portaddr_hash hash table entries: 512 (order:
0, 6144 bytes, linear)
[    1.494171] TCP established hash table entries: 2048 (order: 1, 8192
bytes, linear)
[    1.494293] TCP bind hash table entries: 2048 (order: 2, 16384 bytes,
linear)
[    1.494384] TCP: Hash tables configured (established 2048 bind 2048)
[    1.494659] UDP hash table entries: 256 (order: 1, 8192 bytes, linear)
[    1.494720] UDP-Lite hash table entries: 256 (order: 1, 8192 bytes,
linear)
[    1.495147] NET: Registered protocol family 1
[    1.496826] RPC: Registered named UNIX socket transport module.
[    1.496887] RPC: Registered udp transport module.
[    1.496948] RPC: Registered tcp transport module.
[    1.496978] RPC: Registered tcp NFSv4.1 backchannel transport module.
[    1.497009] PCI: CLS 0 bytes, default 64
[    1.502349] hw perfevents: enabled with armv7_cortex_a8 PMU driver, 5
counters available
[    1.506225] Initialise system trusted keyrings
[    1.506896] workingset: timestamp_bits=14 max_order=16 bucket_order=2
[    1.509490] NFS: Registering the id_resolver key type
[    1.509613] Key type id_resolver registered
[    1.509643] Key type id_legacy registered
[    1.509765] jffs2: version 2.2. (NAND) (SUMMARY)  © 2001-2006 Red
Hat, Inc.
[    1.510559] Key type asymmetric registered
[    1.510620] Asymmetric key parser 'x509' registered
[    1.510681] io scheduler mq-deadline registered
[    1.510742] io scheduler kyber registered
[    1.513214] ti-sysc 480cb024.target-module: sysc_flags 00000100 !=
00000110
[    1.514892] ti-sysc 480c9024.target-module: sysc_flags 00000100 !=
00000110
[    1.519622] pinctrl-single 48002030.pinmux: 284 pins, size 568
[    1.520507] pinctrl-single 48002a00.pinmux: 46 pins, size 92
[    1.521697] pinctrl-single 480025d8.pinmux: 18 pins, size 36
[    1.529388] Serial: 8250/16550 driver, 6 ports, IRQ sharing enabled
[    1.536651] 4806c000.serial: ttyS1 at MMIO 0x4806c000 (irq = 89,
base_baud = 3000000) is a 8250
[    1.537200] serial serial0: tty port ttyS1 registered
[    1.539031] 49020000.serial: ttyS2 at MMIO 0x49020000 (irq = 90,
base_baud = 3000000) is a 8250
[    2.342681] printk: console [ttyS2] enabled
[    2.376953] brd: module loaded
[    2.402435] loop: module loaded
[    2.408569] mtdoops: mtd device (mtddev=name/number) must be supplied
[    2.425079] mdio_bus fixed-0: GPIO lookup for consumer reset
[    2.430847] mdio_bus fixed-0: using lookup tables for GPIO lookup
[    2.437164] mdio_bus fixed-0: No GPIO consumer reset found
[    2.442810] libphy: Fixed MDIO Bus: probed
[    2.450592] i2c /dev entries driver
[    2.457183] sdhci: Secure Digital Host Controller Interface driver
[    2.463562] sdhci: Copyright(c) Pierre Ossman
[    2.469024] omap_hsmmc 4809c000.mmc: GPIO lookup for consumer cd
[    2.475219] omap_hsmmc 4809c000.mmc: using device tree for GPIO lookup
[    2.481964] of_get_named_gpiod_flags: parsed 'cd-gpios' property of
node '/ocp@68000000/mmc@4809c000[0]' - status (0)
[    2.492858] gpio gpiochip5: Persistence not supported for GPIO 0
[    2.498962] omap_gpio 49058000.gpio: Could not set line 0 debounce to
200000 microseconds (-22)
[    2.507843] omap_hsmmc 4809c000.mmc: Got CD GPIO
[    2.512573] omap_hsmmc 4809c000.mmc: GPIO lookup for consumer wp
[    2.518646] omap_hsmmc 4809c000.mmc: using device tree for GPIO lookup
[    2.525329] of_get_named_gpiod_flags: can't parse 'wp-gpios' property
of node '/ocp@68000000/mmc@4809c000[0]'
[    2.535430] of_get_named_gpiod_flags: can't parse 'wp-gpio' property
of node '/ocp@68000000/mmc@4809c000[0]'
[    2.545410] omap_hsmmc 4809c000.mmc: using lookup tables for GPIO lookup
[    2.552246] omap_hsmmc 4809c000.mmc: No GPIO consumer wp found
[    2.560211] omap_hsmmc 480b4000.mmc: GPIO lookup for consumer wp
[    2.566406] random: fast init done
[    2.569885] omap_hsmmc 480b4000.mmc: using device tree for GPIO lookup
[    2.576599] of_get_named_gpiod_flags: can't parse 'wp-gpios' property
of node '/ocp@68000000/mmc@480b4000[0]'
[    2.586700] of_get_named_gpiod_flags: can't parse 'wp-gpio' property
of node '/ocp@68000000/mmc@480b4000[0]'
[    2.596679] omap_hsmmc 480b4000.mmc: using lookup tables for GPIO lookup
[    2.603515] omap_hsmmc 480b4000.mmc: No GPIO consumer wp found
[    2.611206] sdhci-pltfm: SDHCI platform and OF driver helper
[    2.617736] ledtrig-cpu: registered to indicate activity on CPUs
[    2.628387] oprofile: using arm/armv7
[    2.632812] Initializing XFRM netlink socket
[    2.637542] NET: Registered protocol family 10
[    2.644622] Segment Routing with IPv6
[    2.648529] sit: IPv6, IPv4 and MPLS over IPv4 tunneling driver
[    2.656219] NET: Registered protocol family 17
[    2.660797] NET: Registered protocol family 15
[    2.665588] Key type dns_resolver registered
[    2.670288] ThumbEE CPU extension supported.
[    2.674713] Registering SWP/SWPB emulation handler
[    2.683349] SmartReflex Class3 initialized
[    2.688537] Loading compiled-in X.509 certificates
[    2.762573] omap-gpmc 6e000000.gpmc: GPMC revision 5.0
[    2.767852] gpmc_mem_init: disabling cs 0 mapped at 0x0-0x1000000
[    2.774230] gpiochip_find_base: found new base at 508
[    2.780029] gpio gpiochip6: (omap-gpmc): added GPIO chardev (254:6)
[    2.786743] gpiochip_setup_dev: registered GPIOs 508 to 511 on
device: gpiochip6 (omap-gpmc)
[    2.796813] omap2-onenand 1000000.onenand: GPIO lookup for consumer int
[    2.803619] omap2-onenand 1000000.onenand: using device tree for GPIO
lookup
[    2.810791] of_get_named_gpiod_flags: can't parse 'int-gpios'
property of node '/ocp@68000000/gpmc@6e000000/onenand@0,0[0]'
[    2.822143] of_get_named_gpiod_flags: can't parse 'int-gpio' property
of node '/ocp@68000000/gpmc@6e000000/onenand@0,0[0]'
[    2.833343] omap2-onenand 1000000.onenand: using lookup tables for
GPIO lookup
[    2.840667] omap2-onenand 1000000.onenand: No GPIO consumer int found
[    2.847259] omap2-onenand 1000000.onenand: initializing on CS0
(0x01000000), va (ptrval), DMA mode
[    2.856384] OneNAND Manufacturer: Unknown (0xa0)
[    2.863067] smc91x 2000000.ethernet: GPIO lookup for consumer power
[    2.869445] smc91x 2000000.ethernet: using device tree for GPIO lookup
[    2.876220] of_get_named_gpiod_flags: parsed 'power-gpios' property
of node '/ocp@68000000/gpmc@6e000000/ethernet@gpmc[0]' - status (0)
[    2.888702] gpio gpiochip2: Persistence not supported for GPIO 22
[    2.895721] smc91x 2000000.ethernet: GPIO lookup for consumer reset
[    2.902130] smc91x 2000000.ethernet: using device tree for GPIO lookup
[    2.908813] of_get_named_gpiod_flags: parsed 'reset-gpios' property
of node '/ocp@68000000/gpmc@6e000000/ethernet@gpmc[0]' - status (0)
[    2.921264] gpio gpiochip5: Persistence not supported for GPIO 4
[    2.929260] smc91x: not found (-19).
[    2.938476] Skipping twl internal clock init and using bootloader
value (unknown osc rate)
[    2.953124] twl 1-0048: PIH (irq 23) chaining IRQs 146..154
[    2.958984] twl 1-0048: power (irq 151) chaining IRQs 154..161
[    3.002105] V28_A: Bringing 2600000uV into 2800000-2800000uV
[    3.029388] twl4030_gpio twl4030-gpio: gpio (irq 146) chaining IRQs
162..179
[    3.037200] gpiochip_find_base: found new base at 490
[    3.046600] gpio gpiochip7: (twl4030): added GPIO chardev (254:7)
[    3.053070] gpiochip_setup_dev: registered GPIOs 490 to 507 on
device: gpiochip7 (twl4030)
[    3.118835] omap_i2c 48070000.i2c: bus 1 rev3.3 at 2200 kHz
[    3.129852] omap_i2c 48072000.i2c: bus 2 rev3.3 at 100 kHz
[    3.138824] omap_i2c 48060000.i2c: bus 3 rev3.3 at 400 kHz
[    3.145629] omap_hsmmc 4809c000.mmc: GPIO lookup for consumer cd
[    3.151824] omap_hsmmc 4809c000.mmc: using device tree for GPIO lookup
[    3.158508] of_get_named_gpiod_flags: parsed 'cd-gpios' property of
node '/ocp@68000000/mmc@4809c000[0]' - status (0)
[    3.169433] gpio gpiochip5: Persistence not supported for GPIO 0
[    3.175598] omap_gpio 49058000.gpio: Could not set line 0 debounce to
200000 microseconds (-22)
[    3.184448] omap_hsmmc 4809c000.mmc: Got CD GPIO
[    3.189147] omap_hsmmc 4809c000.mmc: GPIO lookup for consumer wp
[    3.195281] omap_hsmmc 4809c000.mmc: using device tree for GPIO lookup
[    3.201965] of_get_named_gpiod_flags: can't parse 'wp-gpios' property
of node '/ocp@68000000/mmc@4809c000[0]'
[    3.212036] of_get_named_gpiod_flags: can't parse 'wp-gpio' property
of node '/ocp@68000000/mmc@4809c000[0]'
[    3.222045] omap_hsmmc 4809c000.mmc: using lookup tables for GPIO lookup
[    3.228820] omap_hsmmc 4809c000.mmc: No GPIO consumer wp found
[    3.266418] omap_hsmmc 480b4000.mmc: GPIO lookup for consumer wp
[    3.272674] omap_hsmmc 480b4000.mmc: using device tree for GPIO lookup
[    3.279327] of_get_named_gpiod_flags: can't parse 'wp-gpios' property
of node '/ocp@68000000/mmc@480b4000[0]'
[    3.289459] of_get_named_gpiod_flags: can't parse 'wp-gpio' property
of node '/ocp@68000000/mmc@480b4000[0]'
[    3.299438] omap_hsmmc 480b4000.mmc: using lookup tables for GPIO lookup
[    3.306274] omap_hsmmc 480b4000.mmc: No GPIO consumer wp found
[    3.346343] hctosys: unable to open rtc device (rtc0)
[    3.352630] smartreflex 480cb000.smartreflex: omap_sr_probe:
SmartReflex driver initialized
[    3.361938] smartreflex 480c9000.smartreflex: omap_sr_probe:
SmartReflex driver initialized
[    3.375061] Waiting for root device /dev/mmcblk0p2...
[    3.740325] mmc1: switch to bus width 8 failed
[    3.745452] mmc1: switch to bus width 4 failed
[    3.749999] mmc1: new high speed MMC card at address 0001
[    3.757476] mmcblk1: mmc1:0001 MMC32G 29.8 GiB
[    3.763092] mmcblk1boot0: mmc1:0001 MMC32G partition 1 512 KiB
[    3.769836] mmcblk1boot1: mmc1:0001 MMC32G partition 2 512 KiB
[    3.779998]  mmcblk1: p1 p2 p3



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Re: mmc0 on Nokia N900 on Linux 5.4.18

[Pavel Machek]

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Hi!

> When booting Linux 5.4.18 with omap2plus_defconfig, I no longer get a
> /dev/mmcblk0 device - the one corresponding to my microSD card, where
> u-boot also loads the kernel from.
> 
> This also likely seems to be a regression, but I haven't tried to hunt
> it down yet.
> 
> Kernel log attached, below.

Do you have back cover attached? That's common trap...

Best regards,
								Pavel
								

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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Re: mmc0 on Nokia N900 on Linux 5.4.18

[Merlijn Wajer]

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Hi,

On 08/02/2020 20:04, Pavel Machek wrote:
> Hi!
> 
>> When booting Linux 5.4.18 with omap2plus_defconfig, I no longer get a
>> /dev/mmcblk0 device - the one corresponding to my microSD card, where
>> u-boot also loads the kernel from.
>>
>> This also likely seems to be a regression, but I haven't tried to hunt
>> it down yet.
>>
>> Kernel log attached, below.
> 
> Do you have back cover attached? That's common trap...

Right.

No, I did not, since I have the serial pins connected to my PC, and the
whole device is mounted on a piece of hardware for that. I thought that
we fixed the problem where we require the cover to be on...

Cheers,
Merlijn


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N900: Remove mmc1 "safety feature"? (was: Re: mmc0 on Nokia N900 on Linux 5.4.18)

[Merlijn Wajer]

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Hi,

On 08/02/2020 20:18, Merlijn Wajer wrote:
> Hi,
> 
> On 08/02/2020 20:04, Pavel Machek wrote:
>> Hi!
>>
>>> When booting Linux 5.4.18 with omap2plus_defconfig, I no longer get a
>>> /dev/mmcblk0 device - the one corresponding to my microSD card, where
>>> u-boot also loads the kernel from.
>>>
>>> This also likely seems to be a regression, but I haven't tried to hunt
>>> it down yet.
>>>
>>> Kernel log attached, below.
>>
>> Do you have back cover attached? That's common trap...
> 
> Right.
> 
> No, I did not, since I have the serial pins connected to my PC, and the
> whole device is mounted on a piece of hardware for that. I thought that
> we fixed the problem where we require the cover to be on...

Indeed, this was the problem.

Is there really a reason to have this in the DTS? I have a hard time
imagining a use case for not showing SD card to users or developers
simply because the casing is open. If anything, this sounds like it
should be a userspace thing.

That said, any opposition to a patch to invert the logic - have users or
developers specifically enable some code to *not* show the MMC card when
the cover is open? Or perhaps just outright remove the check in the
kernel? How about something like the patch below (which we currently ship)?

Cheers,
Merlijn


From 9ce9bb2557208bb347909823d4710c9f93f65bf0 Mon Sep 17 00:00:00 2001
From: Arthur Demchenkov <spinal.by@gmail.com>
Date: Mon, 25 Mar 2019 01:44:23 +0300
Subject: [PATCH] ARM: dts: n900: ignore mmc1 card detect gpio

Allow the device to boot from external MMC with back cover removed.

See https://github.com/maemo-leste/bugtracker/issues/225
---
 arch/arm/boot/dts/omap3-n900.dts | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/arch/arm/boot/dts/omap3-n900.dts
b/arch/arm/boot/dts/omap3-n900.dts
index 7028a7cb2849e..03481302704de 100644
--- a/arch/arm/boot/dts/omap3-n900.dts
+++ b/arch/arm/boot/dts/omap3-n900.dts
@@ -805,10 +805,6 @@
 	pinctrl-0 = <&mmc1_pins>;
 	vmmc-supply = <&vmmc1>;
 	bus-width = <4>;
-	/* For debugging, it is often good idea to remove this GPIO.
-	   It means you can remove back cover (to reboot by removing
-	   battery) and still use the MMC card. */
-	cd-gpios = <&gpio6 0 GPIO_ACTIVE_LOW>; /* 160 */
 };

 /* most boards use vaux3, only some old versions use vmmc2 instead */


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Re: N900: Remove mmc1 "safety feature"? (was: Re: mmc0 on Nokia N900 on Linux 5.4.18)

[Pavel Machek]

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Hi!

> >>> When booting Linux 5.4.18 with omap2plus_defconfig, I no longer get a
> >>> /dev/mmcblk0 device - the one corresponding to my microSD card, where
> >>> u-boot also loads the kernel from.
> >>>
> >>> This also likely seems to be a regression, but I haven't tried to hunt
> >>> it down yet.
> >>>
> >>> Kernel log attached, below.
> >>
> >> Do you have back cover attached? That's common trap...
> > 
> > Right.
> > 
> > No, I did not, since I have the serial pins connected to my PC, and the
> > whole device is mounted on a piece of hardware for that. I thought that
> > we fixed the problem where we require the cover to be on...
> 
> Indeed, this was the problem.
> 
> Is there really a reason to have this in the DTS? I have a hard time
> imagining a use case for not showing SD card to users or developers
> simply because the casing is open. If anything, this sounds like it
> should be a userspace thing.

It is very bad for debugging, agreed.

It makes sense for regular usage: when user removes back cover, system
unmounts the u-SD card, so that it is ready for user to remove
it. Note that we do _not_ have "remove the card safely" button in the
UI; back cover serves that purpose.

That said... for Leste just keep the patch. And maybe apply that one
to shutdown system when battery is low :-).

Best regards,
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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Re: N900: Remove mmc1 "safety feature"? (was: Re: mmc0 on Nokia N900 on Linux 5.4.18)

[Merlijn Wajer]

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Hi,

On 08/02/2020 23:06, Pavel Machek wrote:

> 
> It is very bad for debugging, agreed.
> 
> It makes sense for regular usage: when user removes back cover, system
> unmounts the u-SD card, so that it is ready for user to remove
> it. Note that we do _not_ have "remove the card safely" button in the
> UI; back cover serves that purpose.
> 
> That said... for Leste just keep the patch. And maybe apply that one
> to shutdown system when battery is low :-).

So how does this currently happen, the unmounting? Does the mmc1 card
just disappear from /dev/ without any safe unmount? I don't understand
how the current setup can work from a userspace point of view.

Userspace could react on kernel events that tell it the cover is open,
but I assume the kernel doesn't just decide to nuke the node from /dev/,
so in that case the current DTS setup still doesn't make sense, right?

What am I missing? Could you describe how this would work in a 'real
life' scenario?

Cheers,
Merlijn


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Re: N900: Remove mmc1 "safety feature"? (was: Re: mmc0 on Nokia N900 on Linux 5.4.18)

[Arthur D.]

I suppose the real life scenario would be:

0. The OS runs on eMMC.
1. The user opens his phone back cover and inserts MicroSD card.
2. Kernel doesn't try to access the card until the cover is closed.

It seems wise to me: we don't want to damage user's data or hardware.
Accessing data on unstable medium can't be considered safe.
While the cover is open and user just inserted the microsd card everything
can happen - the phone can be dropped, may be unstable contact to microsd
while the user interacting it, etc.

It seems to be inconvenient for us, while we run OS mostly from microsd.
But removing such behaviour from the kernel completely doesn't seem to
be a good idea generally. Vanilla kernel shouldn't be dedicated for
debugging purposes or edge cases (like running only from external MMC).
Running from embedded MMC should be common for most users in perspective.

If I remember correctly, if the microsd is already mounted and the back
cover is open, nothing bad happens. It continues to work. You can unmount
the card and remove it safely. But you are not going to see the new card
insertion detected until you close the cover.

I'm not sure about the last paragraph. Please correct me if I'm wrong about
how it actually works.


>> It is very bad for debugging, agreed.
>>
>> It makes sense for regular usage: when user removes back cover, system
>> unmounts the u-SD card, so that it is ready for user to remove
>> it. Note that we do _not_ have "remove the card safely" button in the
>> UI; back cover serves that purpose.
>>
>> That said... for Leste just keep the patch. And maybe apply that one
>> to shutdown system when battery is low :-).
>
> So how does this currently happen, the unmounting? Does the mmc1 card
> just disappear from /dev/ without any safe unmount? I don't understand
> how the current setup can work from a userspace point of view.
>
> Userspace could react on kernel events that tell it the cover is open,
> but I assume the kernel doesn't just decide to nuke the node from /dev/,
> so in that case the current DTS setup still doesn't make sense, right?
>
> What am I missing? Could you describe how this would work in a 'real
> life' scenario?

Re: N900: Remove mmc1 "safety feature"? (was: Re: mmc0 on Nokia N900 on Linux 5.4.18)

[Merlijn Wajer]

[-- Attachment #1.1: Type: text/plain, Size: 2351 bytes --]

Hi,

On 09/02/2020 04:48, Arthur D. wrote:
> I suppose the real life scenario would be:
> 
> 0. The OS runs on eMMC.
> 1. The user opens his phone back cover and inserts MicroSD card.
> 2. Kernel doesn't try to access the card until the cover is closed.

This kinda makes sense - but assume the card is already in there, and
the user wants to swap them? Then it doesn't help.


> It seems wise to me: we don't want to damage user's data or hardware.
> Accessing data on unstable medium can't be considered safe.
> While the cover is open and user just inserted the microsd card everything
> can happen - the phone can be dropped, may be unstable contact to microsd
> while the user interacting it, etc.

Maybe I am just used to the microsd port being exposed, but I have no
other ARM device that doesn't have the microsd slot easily exposed. Many
phones, cables, development boards, and they all just allow me to insert
a microSD card, and it'll work. Clearly the manufacturers didn't have a
similar worry there.

> It seems to be inconvenient for us, while we run OS mostly from microsd.
> But removing such behaviour from the kernel completely doesn't seem to
> be a good idea generally. Vanilla kernel shouldn't be dedicated for
> debugging purposes or edge cases (like running only from external MMC).
> Running from embedded MMC should be common for most users in perspective.
> 
> If I remember correctly, if the microsd is already mounted and the back
> cover is open, nothing bad happens. It continues to work. You can unmount
> the card and remove it safely. But you are not going to see the new card
> insertion detected until you close the cover.

I think the last paragraph might actually be key, because when you said
that, my initial reaction was: "aha! that makes some sense".

Still not sure if it warrants the hassle it currently is. And as it
stands, we also disable this feature in Maemo Leste, so we clearly
decided we don't want it either. ;-)

> I'm not sure about the last paragraph. Please correct me if I'm wrong about
> how it actually works.

OK.

If we don't want to remove this, can we at least somehow have a runtime
warning? I spent quite some time searching my dmesg, trying to figure
out why I couldn't even see the mmc interface that I needed.

Cheers,
Merlijn


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Re: N900: Remove mmc1 "safety feature"? (was: Re: mmc0 on Nokia N900 on Linux 5.4.18)

[Aaro Koskinen]

Hi,

On Sun, Feb 09, 2020 at 06:48:47AM +0300, Arthur D. wrote:
> I suppose the real life scenario would be:
> 
> 0. The OS runs on eMMC.
> 1. The user opens his phone back cover and inserts MicroSD card.
> 2. Kernel doesn't try to access the card until the cover is closed.
> 
> It seems wise to me: we don't want to damage user's data or hardware.
> Accessing data on unstable medium can't be considered safe.
> While the cover is open and user just inserted the microsd card everything
> can happen - the phone can be dropped, may be unstable contact to microsd
> while the user interacting it, etc.

If the cover is open, you should also avoid writing to flash or eMMC,
as the battery may get removed easily, and the end result can be bad.

A.

Re: N900: Remove mmc1 "safety feature"? (was: Re: mmc0 on Nokia N900 on Linux 5.4.18)

[Aaro Koskinen]

Hi,

On Sat, Feb 08, 2020 at 11:19:21PM +0100, Merlijn Wajer wrote:
> On 08/02/2020 23:06, Pavel Machek wrote:
> > It is very bad for debugging, agreed.
> > 
> > It makes sense for regular usage: when user removes back cover, system
> > unmounts the u-SD card, so that it is ready for user to remove
> > it. Note that we do _not_ have "remove the card safely" button in the
> > UI; back cover serves that purpose.
> > 
> > That said... for Leste just keep the patch. And maybe apply that one
> > to shutdown system when battery is low :-).
> 
> So how does this currently happen, the unmounting? Does the mmc1 card
> just disappear from /dev/ without any safe unmount? I don't understand
> how the current setup can work from a userspace point of view.
> 
> Userspace could react on kernel events that tell it the cover is open,
> but I assume the kernel doesn't just decide to nuke the node from /dev/,
> so in that case the current DTS setup still doesn't make sense, right?
> 
> What am I missing? Could you describe how this would work in a 'real
> life' scenario?

I don't think it can work with the current mainline kernel.

I recall the original Nokia kernel used the GPIO for "cover switch"
instead of card detect, and it was visible in sysfs, and this allowed
userspace to react on cover removal.. In the mainline kernel we have
this for older Nokia devices (770, N8x0), but not for N900. Still it
wouldn't help much for "safe unmount" as the unmount can take quite a
while, and user may remove the card too early.

A.

Re: N900: Remove mmc1 "safety feature"? (was: Re: mmc0 on Nokia N900 on Linux 5.4.18)

[Merlijn Wajer]

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Hi,

On 10/02/2020 20:27, Aaro Koskinen wrote:

>>
>> So how does this currently happen, the unmounting? Does the mmc1 card
>> just disappear from /dev/ without any safe unmount? I don't understand
>> how the current setup can work from a userspace point of view.
>>
>> Userspace could react on kernel events that tell it the cover is open,
>> but I assume the kernel doesn't just decide to nuke the node from /dev/,
>> so in that case the current DTS setup still doesn't make sense, right?
>>
>> What am I missing? Could you describe how this would work in a 'real
>> life' scenario?
> 
> I don't think it can work with the current mainline kernel.
> 
> I recall the original Nokia kernel used the GPIO for "cover switch"
> instead of card detect, and it was visible in sysfs, and this allowed
> userspace to react on cover removal.. In the mainline kernel we have
> this for older Nokia devices (770, N8x0), but not for N900. Still it
> wouldn't help much for "safe unmount" as the unmount can take quite a
> while, and user may remove the card too early.

Shall I send in a patch removing this check from the device tree, then?

Cheers,
Merlijn


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Re: N900: Remove mmc1 "safety feature"? (was: Re: mmc0 on Nokia N900 on Linux 5.4.18)

[Sebastian Reichel]

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Hi,

On Wed, Feb 12, 2020 at 02:02:53PM +0100, Merlijn Wajer wrote:
> On 10/02/2020 20:27, Aaro Koskinen wrote:
> >> So how does this currently happen, the unmounting? Does the mmc1 card
> >> just disappear from /dev/ without any safe unmount? I don't understand
> >> how the current setup can work from a userspace point of view.
> >>
> >> Userspace could react on kernel events that tell it the cover is open,
> >> but I assume the kernel doesn't just decide to nuke the node from /dev/,
> >> so in that case the current DTS setup still doesn't make sense, right?
> >>
> >> What am I missing? Could you describe how this would work in a 'real
> >> life' scenario?
> > 
> > I don't think it can work with the current mainline kernel.
> > 
> > I recall the original Nokia kernel used the GPIO for "cover switch"
> > instead of card detect, and it was visible in sysfs, and this allowed
> > userspace to react on cover removal.. In the mainline kernel we have
> > this for older Nokia devices (770, N8x0), but not for N900. Still it
> > wouldn't help much for "safe unmount" as the unmount can take quite a
> > while, and user may remove the card too early.
> 
> Shall I send in a patch removing this check from the device tree, then?

I agree it's mostly annoying and suggest to convert the GPIO
into a gpio-key using a newly defined

SW_MACHINE_COVER /* set = cover closed */

Similar to the camera lens cover. It means userspace has a chance to
show a warning, but system works generally. I think it's ok to
assume that people running mainline on their N900 nowadays know what
could happen when they hot-remove SD cards.

-- Sebastian

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Re: N900: Remove mmc1 "safety feature"?

[Ivaylo Dimitrov]

Hi,

On 14.02.20 г. 3:39 ч., Sebastian Reichel wrote:
> Hi,
> 
> On Wed, Feb 12, 2020 at 02:02:53PM +0100, Merlijn Wajer wrote:
>> On 10/02/2020 20:27, Aaro Koskinen wrote:
>>>> So how does this currently happen, the unmounting? Does the mmc1 card
>>>> just disappear from /dev/ without any safe unmount? I don't understand
>>>> how the current setup can work from a userspace point of view.
>>>>
>>>> Userspace could react on kernel events that tell it the cover is open,
>>>> but I assume the kernel doesn't just decide to nuke the node from /dev/,
>>>> so in that case the current DTS setup still doesn't make sense, right?
>>>>
>>>> What am I missing? Could you describe how this would work in a 'real
>>>> life' scenario?
>>>
>>> I don't think it can work with the current mainline kernel.
>>>
>>> I recall the original Nokia kernel used the GPIO for "cover switch"
>>> instead of card detect, and it was visible in sysfs, and this allowed
>>> userspace to react on cover removal.. In the mainline kernel we have
>>> this for older Nokia devices (770, N8x0), but not for N900. Still it
>>> wouldn't help much for "safe unmount" as the unmount can take quite a
>>> while, and user may remove the card too early.
>>
>> Shall I send in a patch removing this check from the device tree, then?
> 
> I agree it's mostly annoying and suggest to convert the GPIO
> into a gpio-key using a newly defined
> 
> SW_MACHINE_COVER /* set = cover closed */
> 
> Similar to the camera lens cover. It means userspace has a chance to
> show a warning, but system works generally. I think it's ok to
> assume that people running mainline on their N900 nowadays know what
> could happen when they hot-remove SD cards.
> 

That sounds way better to me than just removing the check.

Regards,
Ivo

Re: N900: Remove mmc1 "safety feature"?

[Tony Lindgren]

* Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com> [200214 05:52]:
> Hi,
> 
> On 14.02.20 г. 3:39 ч., Sebastian Reichel wrote:
> > Hi,
> > 
> > On Wed, Feb 12, 2020 at 02:02:53PM +0100, Merlijn Wajer wrote:
> > > On 10/02/2020 20:27, Aaro Koskinen wrote:
> > > > > So how does this currently happen, the unmounting? Does the mmc1 card
> > > > > just disappear from /dev/ without any safe unmount? I don't understand
> > > > > how the current setup can work from a userspace point of view.
> > > > > 
> > > > > Userspace could react on kernel events that tell it the cover is open,
> > > > > but I assume the kernel doesn't just decide to nuke the node from /dev/,
> > > > > so in that case the current DTS setup still doesn't make sense, right?
> > > > > 
> > > > > What am I missing? Could you describe how this would work in a 'real
> > > > > life' scenario?
> > > > 
> > > > I don't think it can work with the current mainline kernel.
> > > > 
> > > > I recall the original Nokia kernel used the GPIO for "cover switch"
> > > > instead of card detect, and it was visible in sysfs, and this allowed
> > > > userspace to react on cover removal.. In the mainline kernel we have
> > > > this for older Nokia devices (770, N8x0), but not for N900. Still it
> > > > wouldn't help much for "safe unmount" as the unmount can take quite a
> > > > while, and user may remove the card too early.
> > > 
> > > Shall I send in a patch removing this check from the device tree, then?
> > 
> > I agree it's mostly annoying and suggest to convert the GPIO
> > into a gpio-key using a newly defined
> > 
> > SW_MACHINE_COVER /* set = cover closed */
> > 
> > Similar to the camera lens cover. It means userspace has a chance to
> > show a warning, but system works generally. I think it's ok to
> > assume that people running mainline on their N900 nowadays know what
> > could happen when they hot-remove SD cards.
> > 
> 
> That sounds way better to me than just removing the check.

Sounds good to me too. The MMC card is there and usable when cover is
off, so the cover GPIO is not the same as MMC detect GPIO.

Regards,

Tony

Re: N900: Remove mmc1 "safety feature"? (was: Re: mmc0 on Nokia N900 on Linux 5.4.18)

[Merlijn Wajer]

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Hi,

On 14/02/2020 02:39, Sebastian Reichel wrote:
> Hi,
> 
>> Shall I send in a patch removing this check from the device tree, then?
> 
> I agree it's mostly annoying and suggest to convert the GPIO
> into a gpio-key using a newly defined
> 
> SW_MACHINE_COVER /* set = cover closed */
> 
> Similar to the camera lens cover. It means userspace has a chance to
> show a warning, but system works generally. I think it's ok to
> assume that people running mainline on their N900 nowadays know what
> could happen when they hot-remove SD cards.

OK, I will make a patch. Thanks!

Cheers,
Merlijn



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