October 2014 - kernelnewbies@kernelnewbies.org

ARM: dts: Passing 'irq' property in SPI child node
by BhuvanChandra DharanikotaVenkata Oct. 30, 2014

Oct. 30, 2014

Hi all, Facing some issues while passing the *irq* property in child node of SPI node. I was trying to enable the SPI based mcp2515 can controller, according to the documentation available in the bindings of mcp251x driver, added the required properties of the node. As per the requirement need to pass an irq of a GPIO, used 'interrupt-parent' and 'interrupts' properties in the child node (mcp251x can node). I had a doubt, how exactly the interrupts property was parsed and taken in the mcp251x driver? In driver the *spi->irq* holds the irq number, in non dt kernels we are passing the irq value directly from platform data. How can we pass the *irq* property required by mcp251x driver from the device tree node? http://lxr.free-electrons.com/source/Documentation/devicetree/bindings/net/… http://lxr.free-electrons.com/source/drivers/net/can/mcp251x.c?v=2.6.33 spi dt node: &dspi1 { > status = "okay"; > spi-max-frequency = <25000000>; > > can2: can@1 { > compatible = "microchip,mcp2515"; > reg = <0>; > clocks = <&clk16m>; > interrupt-parent = <&gpio2>; > interrupts = <43 0x8>; > spi-max-frequency = <10000000>; > }; > }; Best Regards, Bhuvanchandara DV

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Query on the ci_udc driver for USB client implementation
by Victor Ascroft Oct. 30, 2014

Oct. 30, 2014

Hello, I am currently implementing USB Host and client support for Freescale Vybrid platform in u-boot. I managed to get the host implementation working. For the host side, usb start calls usb_init(), which in turns call, usb_lowlevel_init(), from there into the ehic_hcd_init() of my implementation. So, setting up the necessary clocks and plls for USB in my implementation and then setting up the usb_ehci, ehci_hccr and echi_hcor structures was all. The flow and setup required i was able to trace. The USB client part is not clear to me. I was thinking i can use the ci_udc driver somehow to implement the client part. How can i use the ci_udc driver to implement client functionality?. From what i could see, the usb_gadget_driver_register() is suppose to be the first call. But, i couldn't trace from where this gets called or the flow and setup is suppose to be. OR Is a separate client driver required and nothing generic can be used akin to how it could be done for host? Sorry if i am asking this question in the wrong place. I couldn't find anyone in the u-boot IRC channel nor find something similar to the kernel-newbies mailing list. Hope i am asking the right questions. Sorry if this mail ends up two times in this list, i mistakenly tried sending it from the mail ID not registered with this mailing list. Thanks & Regards, Sanchayan Maity.

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Query on the ci_udc driver for USB client implementation
by Sanchayan Maity Oct. 30, 2014

Oct. 30, 2014

Hello, I am currently implementing USB Host and client support for Freescale Vybrid platform in u-boot. I managed to get the host implementation working. For the host side, usb start calls usb_init(), which in turns call, usb_lowlevel_init(), from there into the ehic_hcd_init() of my implementation. So, setting up the necessary clocks and plls for USB in my implementation and then setting up the usb_ehci, ehci_hccr and echi_hcor structures was all. The flow and setup required i was able to trace. The USB client part is not clear to me. I was thinking i can use the ci_udc driver somehow to implement the client part. How can i use the ci_udc driver to implement client functionality?. From what i could see, the usb_gadget_driver_register() is suppose to be the first call. But, i couldn't trace from where this gets called or the flow and setup is suppose to be. OR Is a separate client driver required and nothing generic can be used akin to how it could be done for host? Sorry if i am asking this question in the wrong place. I couldn't find anyone in the u-boot IRC channel nor find something similar to the kernel-newbies mailing list. Hope i am asking the right questions. Thanks & Regards, Sanchayan Maity.

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Network subsystem and suggestions
by Jaime Arrocha Oct. 29, 2014

Oct. 29, 2014

Hello all, I would like to ask the reason behind the talk about the FreeBSD being faster that Linux when talking about the network stack. I have visited some blogs which appear biased and they only talk about multi-threading networking. Is it in the quality of interrupt handlers? Also, I came across these books. UNIX Internals: The New Frontiers by Uresh Vahalia UNIX Systems for Modern Architectures by Curt Schimmel Will they be good reads (still relevant?) after reading the Linux books from R.Love and W.Mauerer. Lastly, what about this other book? The Design of the UNIX Operating System by Maurice Bach Is there a more modern book that touch on the same topics? Would a read be worth in the future? I am trying to build a main track of books to read. Thank you.

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回覆: [PATCH] sta;ging: rtl8723au: Fix brace coding style issues reported by checkpatch
by stevecfhsieh＠gmail.com Oct. 29, 2014

Oct. 29, 2014

從我的 HTC 寄出 ----- Reply message ----- 寄件者： "Jeff Kirsher" <jeffrey.t.kirsher(a)intel.com> 收件者： "nick" <xerofoify(a)gmail.com> 副本： "Greg Donald" <gdonald(a)gmail.com>, "Greg Freemyer" <greg.freemyer(a)gmail.com>, "kernelnewbies" <kernelnewbies(a)kernelnewbies.org> 主旨： [PATCH] staging: rtl8723au: Fix brace coding style issues reported by checkpatch 日期：週三, 10 月 29 日, 2014 年 10:04 上午 On Tue, 2014-10-28 at 22:01 -0400, nick wrote: > Greg, > That's fine, I was wondering how long Greg KH takes to get around to picking this up as he is very busy with > other kernel work. > Cheers Nick I am Jeff and I was the one that responded... > > On 14-10-28 09:58 PM, Jeff Kirsher wrote: > > On Tue, 2014-10-28 at 21:49 -0400, nick wrote: > >> Greg, > >> Not picked up of yet. I would appreciate if this gets forwarded for me as this may help it get picked up. > >> Further more this issues I am were causing were not technical but not listening and that's why I decided > >> to state around and learn how to my patches properly. > >> Cheers Nick > >> > > > > I saw you updated you patch Nick, thanks. I feel I can safely put my > > Reviewed-by: on it. Also, if Greg KH (staging maintainer) has not > > picked up in the next day or so, I will submit your patch to the staging > > tree for you. > > > >> > >> On 14-10-28 05:31 PM, Greg Donald wrote: > >>> On Tue, Oct 28, 2014 at 2:52 PM, nick <xerofoify(a)gmail.com> wrote: > >>>> I am trying to improve my code as much as possible now, I really am finally understanding > >>>> how terrible my code was before and I hope never again to make patches that shitty. > >>> > >>> I don't think your recent progress has gone unnoticed. Any word on > >>> your latest patch getting picked up? It looked good to me. > >>> > >>> You remind me of John Locke from Lost. "Don't tell me what I can't do!" :) > >>> > >>> > > > >

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Where to put the source of a DD of a custom hardware.
by Raphael Philipe Oct. 29, 2014

Oct. 29, 2014

Hi, I'm developing a device driver to drive a specific custom hardware, that is implemented in FPGA. Since it is an application specific device driver, where (in witch folder) should I put Its source in my local kernel source tree? Is there any guideline or best practice about it? This device driver is basically a character device, that copies stuff from hardware to kernel space and then from user space. Regards, Raphael

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Struct msghdr
by Grzegorz Dwornicki Oct. 29, 2014

Oct. 29, 2014

Hello I have a question about this structure. It has 2 fields. One is iov_base the pointer of type void. Second is iov_len of type size_t. This is interesting: iov_len has always a value of 8190. How does it impact the iov_base? I mean does iov_base is built from other structures? If soo where I can find them? I can't find the definition of this structure in the kernel sources... The man page for recv variations have it. Thx for all the help Grzegorz.

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Re: The Eudyptula Challenge
by Robert van Gend Oct. 28, 2014

Oct. 28, 2014

Hi I would like to join the challenge

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Some Kernel Questions/Confusions [Pls help]
by Er Krishna Oct. 28, 2014

Oct. 28, 2014

Hi All, Pls help me here by answering following two queries. If my understanding is incorrect in asking the question pls correct me: 1. In case of Paging and discontiguous memory allocation for a particular process, is it possible that all the segments say DS, SS, CS, Heap and all can be in different page frames. I am asking this for a particular segment (I know all the segments can be in different non contiguous pages seperately, but what about one segment in different non contiguous page frames). For example lets say stack segment (or data segment) which is in RAM requires 45 pages and in RAM 45 pages are not contiguous avilable, so can it be reside from page frame no 100-125 and then again in 140-160 ? 2. In case of execution of fast interrupt handler when other interrupts are disable, if device controller generate interrupt then it will not reaches to CPU ? Is it loss of interrupts and not a good condition on system/driver ? Can we ignore it safely for our driver or we must not fall into this scenario ? 3. Inside kernel page fault should not happen, I was trying to understand it w.r.t copy from/to usr api. Say on usr address the particular page is not there and kernel wants to copy it in kernel address space? What will happen if we use memcpy rather than copy from usr, will the kernel crash due to page fault? how copy from usr prevents this? Is the page fault handler code always remains in RAM in case of Linux Kernel ? 4. In case of read/write system call, a normal user program wants to acess some file or more specifically (direct or indirect block of particular inode). This user space process page table which is in RAM doesn't contain valid bit for particular pages which correspond to these blocks. If these blocks are not in page-cache, it will be bring ito RAM by vector i/o with the help of bio-vec data structures. Will this scenario triggers the page fault inside kernel ? Best Regards, Krishna

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[PATCH] staging: rtl8723au: Fix brace coding style issues reported by checkpatch
by Nicholas Krause Oct. 28, 2014

Oct. 28, 2014

Fix the curley braces that do not reside on the same line because this does not follow the kernel coding style and causes checkpatch.pl warnings. Signed-off-by: Nicholas Krause <xerofoify(a)gmail.com> --- drivers/staging/rtl8723au/core/rtw_ap.c | 138 ++++++++++---------------------- 1 file changed, 43 insertions(+), 95 deletions(-) diff --git a/drivers/staging/rtl8723au/core/rtw_ap.c b/drivers/staging/rtl8723au/core/rtw_ap.c index 75ae249..3301a2c 100644 --- a/drivers/staging/rtl8723au/core/rtw_ap.c +++ b/drivers/staging/rtl8723au/core/rtw_ap.c @@ -231,12 +231,10 @@ void expire_timeout_chk23a(struct rtw_adapter *padapter) psta->expire_to--; } - if (psta->expire_to <= 0) - { + if (psta->expire_to <= 0) { struct mlme_ext_priv *pmlmeext = &padapter->mlmeextpriv; - if (padapter->registrypriv.wifi_spec == 1) - { + if (padapter->registrypriv.wifi_spec == 1) { psta->expire_to = pstapriv->expire_to; continue; } @@ -308,15 +306,12 @@ void expire_timeout_chk23a(struct rtw_adapter *padapter) ret = issue_nulldata23a(padapter, psta->hwaddr, 0, 3, 50); psta->keep_alive_trycnt++; - if (ret == _SUCCESS) - { + if (ret == _SUCCESS) { DBG_8723A("asoc check, sta(" MAC_FMT ") is alive\n", MAC_ARG(psta->hwaddr)); psta->expire_to = pstapriv->expire_to; psta->keep_alive_trycnt = 0; continue; - } - else if (psta->keep_alive_trycnt <= 3) - { + } else if (psta->keep_alive_trycnt <= 3) { DBG_8723A("ack check for asoc expire, keep_alive_trycnt =%d\n", psta->keep_alive_trycnt); psta->expire_to = 1; continue; @@ -363,8 +358,7 @@ void add_RATid23a(struct rtw_adapter *padapter, struct sta_info *psta, u8 rssi_l return; /* b/g mode ra_bitmap */ - for (i = 0; i < sizeof(psta->bssrateset); i++) - { + for (i = 0; i < sizeof(psta->bssrateset); i++) { if (psta->bssrateset[i]) tx_ra_bitmap |= rtw_get_bit_value_from_ieee_value23a(psta->bssrateset[i]&0x7f); } @@ -406,8 +400,7 @@ void add_RATid23a(struct rtw_adapter *padapter, struct sta_info *psta, u8 rssi_l raid = networktype_to_raid23a(sta_band); init_rate = get_highest_rate_idx23a(tx_ra_bitmap&0x0fffffff)&0x3f; - if (psta->aid < NUM_STA) - { + if (psta->aid < NUM_STA) { u8 arg = 0; arg = psta->mac_id&0x1f; @@ -436,9 +429,7 @@ void add_RATid23a(struct rtw_adapter *padapter, struct sta_info *psta, u8 rssi_l psta->raid = raid; psta->init_rate = init_rate; - } - else - { + } else { DBG_8723A("station aid %d exceed the max number\n", psta->aid); } } @@ -453,8 +444,7 @@ static void update_bmc_sta(struct rtw_adapter *padapter) struct wlan_bssid_ex *pcur_network = &pmlmepriv->cur_network.network; struct sta_info *psta = rtw_get_bcmc_stainfo23a(padapter); - if (psta) - { + if (psta) { psta->aid = 0;/* default set to 0 */ psta->mac_id = psta->aid + 1; @@ -474,8 +464,7 @@ static void update_bmc_sta(struct rtw_adapter *padapter) psta->bssratelen = supportRateNum; /* b/g mode ra_bitmap */ - for (i = 0; i < supportRateNum; i++) - { + for (i = 0; i < supportRateNum; i++) { if (psta->bssrateset[i]) tx_ra_bitmap |= rtw_get_bit_value_from_ieee_value23a(psta->bssrateset[i]&0x7f); } @@ -522,9 +511,7 @@ static void update_bmc_sta(struct rtw_adapter *padapter) psta->state = _FW_LINKED; spin_unlock_bh(&psta->lock); - } - else - { + } else { DBG_8723A("add_RATid23a_bmc_sta error!\n"); } } @@ -561,8 +548,7 @@ void update_sta_info23a_apmode23a(struct rtw_adapter *padapter, struct sta_info /* ERP */ VCS_update23a(padapter, psta); /* HT related cap */ - if (phtpriv_sta->ht_option) - { + if (phtpriv_sta->ht_option) { /* check if sta supports rx ampdu */ phtpriv_sta->ampdu_enable = phtpriv_ap->ampdu_enable; @@ -580,9 +566,7 @@ void update_sta_info23a_apmode23a(struct rtw_adapter *padapter, struct sta_info psta->qos_option = true; - } - else - { + } else { phtpriv_sta->ampdu_enable = false; phtpriv_sta->sgi = false; @@ -1258,8 +1242,7 @@ void update_beacon23a(struct rtw_adapter *padapter, u8 ie_id, u8 *oui, u8 tx) spin_lock_bh(&pmlmepriv->bcn_update_lock); - switch (ie_id) - { + switch (ie_id) { case 0xFF: /* 8: TimeStamp, 2: Beacon Interval 2:Capability */ update_bcn_fixed_ie(padapter); @@ -1386,8 +1369,7 @@ static int rtw_ht_operation_update(struct rtw_adapter *padapter) void associated_clients_update23a(struct rtw_adapter *padapter, u8 updated) { /* update associated stations cap. */ - if (updated == true) - { + if (updated == true) { struct list_head *phead, *plist, *ptmp; struct sta_info *psta; struct sta_priv *pstapriv = &padapter->stapriv; @@ -1413,34 +1395,27 @@ void bss_cap_update_on_sta_join23a(struct rtw_adapter *padapter, struct sta_info struct mlme_priv *pmlmepriv = &padapter->mlmepriv; struct mlme_ext_priv *pmlmeext = &padapter->mlmeextpriv; - if (!(psta->flags & WLAN_STA_SHORT_PREAMBLE)) - { - if (!psta->no_short_preamble_set) - { + if (!(psta->flags & WLAN_STA_SHORT_PREAMBLE)) { + if (!psta->no_short_preamble_set) { psta->no_short_preamble_set = 1; pmlmepriv->num_sta_no_short_preamble++; if ((pmlmeext->cur_wireless_mode > WIRELESS_11B) && - (pmlmepriv->num_sta_no_short_preamble == 1)) - { + (pmlmepriv->num_sta_no_short_preamble == 1)) { beacon_updated = true; update_beacon23a(padapter, 0xFF, NULL, true); } } - } - else - { - if (psta->no_short_preamble_set) - { + } else { + if (psta->no_short_preamble_set) { psta->no_short_preamble_set = 0; pmlmepriv->num_sta_no_short_preamble--; if ((pmlmeext->cur_wireless_mode > WIRELESS_11B) && - (pmlmepriv->num_sta_no_short_preamble == 0)) - { + (pmlmepriv->num_sta_no_short_preamble == 0)) { beacon_updated = true; update_beacon23a(padapter, 0xFF, NULL, true); } @@ -1448,32 +1423,25 @@ void bss_cap_update_on_sta_join23a(struct rtw_adapter *padapter, struct sta_info } } - if (psta->flags & WLAN_STA_NONERP) - { - if (!psta->nonerp_set) - { + if (psta->flags & WLAN_STA_NONERP) { + if (!psta->nonerp_set) { psta->nonerp_set = 1; pmlmepriv->num_sta_non_erp++; - if (pmlmepriv->num_sta_non_erp == 1) - { + if (pmlmepriv->num_sta_non_erp == 1) { beacon_updated = true; update_beacon23a(padapter, WLAN_EID_ERP_INFO, NULL, true); } } - } - else - { - if (psta->nonerp_set) - { + } else { + if (psta->nonerp_set) { psta->nonerp_set = 0; pmlmepriv->num_sta_non_erp--; - if (pmlmepriv->num_sta_non_erp == 0) - { + if (pmlmepriv->num_sta_non_erp == 0) { beacon_updated = true; update_beacon23a(padapter, WLAN_EID_ERP_INFO, NULL, true); } @@ -1481,42 +1449,34 @@ void bss_cap_update_on_sta_join23a(struct rtw_adapter *padapter, struct sta_info } - if (!(psta->capability & WLAN_CAPABILITY_SHORT_SLOT_TIME)) - { - if (!psta->no_short_slot_time_set) - { + if (!(psta->capability & WLAN_CAPABILITY_SHORT_SLOT_TIME)) { + if (!psta->no_short_slot_time_set) { psta->no_short_slot_time_set = 1; pmlmepriv->num_sta_no_short_slot_time++; if ((pmlmeext->cur_wireless_mode > WIRELESS_11B) && - (pmlmepriv->num_sta_no_short_slot_time == 1)) - { + (pmlmepriv->num_sta_no_short_slot_time == 1)) { beacon_updated = true; update_beacon23a(padapter, 0xFF, NULL, true); } } - } - else - { - if (psta->no_short_slot_time_set) - { + } else { + if (psta->no_short_slot_time_set) { psta->no_short_slot_time_set = 0; pmlmepriv->num_sta_no_short_slot_time--; if ((pmlmeext->cur_wireless_mode > WIRELESS_11B) && - (pmlmepriv->num_sta_no_short_slot_time == 0)) - { + (pmlmepriv->num_sta_no_short_slot_time == 0)) { beacon_updated = true; update_beacon23a(padapter, 0xFF, NULL, true); } } } - if (psta->flags & WLAN_STA_HT) - { + if (psta->flags & WLAN_STA_HT) { u16 ht_capab = le16_to_cpu(psta->htpriv.ht_cap.cap_info); DBG_8723A("HT: STA " MAC_FMT " HT Capabilities " @@ -1549,9 +1509,7 @@ void bss_cap_update_on_sta_join23a(struct rtw_adapter *padapter, struct sta_info pmlmepriv->num_sta_ht_20mhz); } - } - else - { + } else { if (!psta->no_ht_set) { psta->no_ht_set = 1; pmlmepriv->num_sta_no_ht++; @@ -1564,8 +1522,7 @@ void bss_cap_update_on_sta_join23a(struct rtw_adapter *padapter, struct sta_info } } - if (rtw_ht_operation_update(padapter) > 0) - { + if (rtw_ht_operation_update(padapter) > 0) { update_beacon23a(padapter, WLAN_EID_HT_CAPABILITY, NULL, false); update_beacon23a(padapter, WLAN_EID_HT_OPERATION, NULL, true); } @@ -1589,8 +1546,7 @@ u8 bss_cap_update_on_sta_leave23a(struct rtw_adapter *padapter, struct sta_info psta->no_short_preamble_set = 0; pmlmepriv->num_sta_no_short_preamble--; if (pmlmeext->cur_wireless_mode > WIRELESS_11B - && pmlmepriv->num_sta_no_short_preamble == 0) - { + && pmlmepriv->num_sta_no_short_preamble == 0) { beacon_updated = true; update_beacon23a(padapter, 0xFF, NULL, true); } @@ -1599,8 +1555,7 @@ u8 bss_cap_update_on_sta_leave23a(struct rtw_adapter *padapter, struct sta_info if (psta->nonerp_set) { psta->nonerp_set = 0; pmlmepriv->num_sta_non_erp--; - if (pmlmepriv->num_sta_non_erp == 0) - { + if (pmlmepriv->num_sta_non_erp == 0) { beacon_updated = true; update_beacon23a(padapter, WLAN_EID_ERP_INFO, NULL, true); @@ -1611,8 +1566,7 @@ u8 bss_cap_update_on_sta_leave23a(struct rtw_adapter *padapter, struct sta_info psta->no_short_slot_time_set = 0; pmlmepriv->num_sta_no_short_slot_time--; if (pmlmeext->cur_wireless_mode > WIRELESS_11B - && pmlmepriv->num_sta_no_short_slot_time == 0) - { + && pmlmepriv->num_sta_no_short_slot_time == 0) { beacon_updated = true; update_beacon23a(padapter, 0xFF, NULL, true); } @@ -1633,8 +1587,7 @@ u8 bss_cap_update_on_sta_leave23a(struct rtw_adapter *padapter, struct sta_info pmlmepriv->num_sta_ht_20mhz--; } - if (rtw_ht_operation_update(padapter) > 0) - { + if (rtw_ht_operation_update(padapter) > 0) { update_beacon23a(padapter, WLAN_EID_HT_CAPABILITY, NULL, false); update_beacon23a(padapter, WLAN_EID_HT_OPERATION, NULL, true); } @@ -1654,8 +1607,7 @@ u8 ap_free_sta23a(struct rtw_adapter *padapter, struct sta_info *psta, bool acti if (!psta) return beacon_updated; - if (active == true) - { + if (active == true) { /* tear down Rx AMPDU */ send_delba23a(padapter, 0, psta->hwaddr);/* recipient */ @@ -1783,13 +1735,10 @@ void sta_info_update23a(struct rtw_adapter *padapter, struct sta_info *psta) psta->qos_option = 0; /* update 802.11n ht cap. */ - if (WLAN_STA_HT&flags) - { + if (WLAN_STA_HT&flags) { psta->htpriv.ht_option = true; psta->qos_option = 1; - } - else - { + } else { psta->htpriv.ht_option = false; } @@ -1802,8 +1751,7 @@ void sta_info_update23a(struct rtw_adapter *padapter, struct sta_info *psta) /* called >= TSR LEVEL for USB or SDIO Interface*/ void ap_sta_info_defer_update23a(struct rtw_adapter *padapter, struct sta_info *psta) { - if (psta->state & _FW_LINKED) - { + if (psta->state & _FW_LINKED) { /* add ratid */ add_RATid23a(padapter, psta, 0);/* DM_RATR_STA_INIT */ } -- 1.9.1

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