lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Message-ID: <4c40fbe4-3492-ec76-e452-3a3ecb0f2433@ti.com> Date: Fri, 11 Aug 2023 10:24:18 -0500 From: Andrew Davis <afd@...com> To: Md Danish Anwar <a0501179@...com>, MD Danish Anwar <danishanwar@...com>, Randy Dunlap <rdunlap@...radead.org>, Roger Quadros <rogerq@...nel.org>, Simon Horman <simon.horman@...igine.com>, Vignesh Raghavendra <vigneshr@...com>, Andrew Lunn <andrew@...n.ch>, Richard Cochran <richardcochran@...il.com>, Conor Dooley <conor+dt@...nel.org>, Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>, Rob Herring <robh+dt@...nel.org>, Paolo Abeni <pabeni@...hat.com>, Jakub Kicinski <kuba@...nel.org>, Eric Dumazet <edumazet@...gle.com>, "David S. Miller" <davem@...emloft.net> CC: <nm@...com>, <srk@...com>, <linux-kernel@...r.kernel.org>, <devicetree@...r.kernel.org>, <netdev@...r.kernel.org>, <linux-omap@...r.kernel.org>, <linux-arm-kernel@...ts.infradead.org> Subject: Re: [PATCH v3 3/5] net: ti: icss-iep: Add IEP driver On 8/10/23 6:50 AM, Md Danish Anwar wrote: > Hi Andrew, > > On 09/08/23 8:30 pm, Andrew Davis wrote: >> On 8/9/23 6:49 AM, MD Danish Anwar wrote: >>> From: Roger Quadros <rogerq@...com> >>> >>> Add a driver for Industrial Ethernet Peripheral (IEP) block of PRUSS to >>> support timestamping of ethernet packets and thus support PTP and PPS >>> for PRU ethernet ports. >>> >>> Signed-off-by: Roger Quadros <rogerq@...com> >>> Signed-off-by: Lokesh Vutla <lokeshvutla@...com> >>> Signed-off-by: Murali Karicheri <m-karicheri2@...com> >>> Signed-off-by: Vignesh Raghavendra <vigneshr@...com> >>> Signed-off-by: MD Danish Anwar <danishanwar@...com> >>> --- >>> drivers/net/ethernet/ti/Kconfig | 12 + >>> drivers/net/ethernet/ti/Makefile | 1 + >>> drivers/net/ethernet/ti/icssg/icss_iep.c | 935 +++++++++++++++++++++++ >>> drivers/net/ethernet/ti/icssg/icss_iep.h | 38 + >>> 4 files changed, 986 insertions(+) >>> create mode 100644 drivers/net/ethernet/ti/icssg/icss_iep.c >>> create mode 100644 drivers/net/ethernet/ti/icssg/icss_iep.h >>> >>> diff --git a/drivers/net/ethernet/ti/Kconfig b/drivers/net/ethernet/ti/Kconfig >>> index 63e510b6860f..88b5b1b47779 100644 >>> --- a/drivers/net/ethernet/ti/Kconfig >>> +++ b/drivers/net/ethernet/ti/Kconfig >>> @@ -186,6 +186,7 @@ config CPMAC >>> config TI_ICSSG_PRUETH >>> tristate "TI Gigabit PRU Ethernet driver" >>> select PHYLIB >>> + select TI_ICSS_IEP >> >> Why not save selecting this until you add its use in the ICSSG_PRUETH driver in >> the next patch. >> > > The next patch is only adding changes to icssg-prueth .c /.h files. This patch > is adding changes to Kconfig and the Makefile. To keep it that way selecting > this is added in this patch. No worries, I will move this to next patch. > >> [...] >> >>> + >>> +static u32 icss_iep_readl(struct icss_iep *iep, int reg) >>> +{ >>> + return readl(iep->base + iep->plat_data->reg_offs[reg]); >>> +} >> >> Do these one line functions really add anything? Actually why >> not use the regmap you have here. > > These one line functions are not really adding anything but they are acting as > a wrapper around readl /writel and providing some sort of encapsulation as > directly calling readl will result in a little complicated code. > > /* WIth One line function */ > ts_lo = icss_iep_readl(iep, ICSS_IEP_COUNT_REG0); > > /* Without one line function */ > ts_lo = readl(iep->base, iep->plat_data->reg_offs[ICSS_IEP_COUNT_REG0]); > > Previously regmap was used in this driver. But in older commit [1] in > 5.10-ti-linux-kernel (Before I picked the driver for upstream) it got changed > to readl / writel stating that regmap_read / write is too slow. IEP is time > sensitive and needs faster read and write, probably because of this they > changed it. > Sounds like you only need direct register access for time sensitive gettime/settime functions, if that is the only place writel()/readl() is needed just drop the helper and use directly in that one spot. >> >> [...] >> >>> +static void icss_iep_enable(struct icss_iep *iep) >>> +{ >>> + regmap_update_bits(iep->map, ICSS_IEP_GLOBAL_CFG_REG, >>> + IEP_GLOBAL_CFG_CNT_ENABLE, >>> + IEP_GLOBAL_CFG_CNT_ENABLE); >> >> Have you looked into regmap_fields? >> > > No I hadn't. But now I looked into regmap_fields, seems to be another way to > update the bits, instead of passing mask and value, regmap_filed_read / write > only takes the value. But for that we will need to create a regmap field. If > you want me to switch to regmap_fields instead of regmap_update_bits I can make > the changes. But I am fine with regmap_update_bits(). > I'm suggesting regmap fields as I have used it several times and it resulted in greatly improved readability. Yes you will need a regmap field table, but that is the best part, it lets you put all your bit definitions in one spot that can match 1:1 with the datasheet, much easier to check for correctness than if the bit usages are all spread out in the driver. I won't insist on you converting this driver to use it today, but I do recommend you at least give it a shot for your own learning. Andrew >> [...] >> >>> + >>> + if (!!(iep->latch_enable & BIT(index)) == !!on) >>> + goto exit; >>> + >> >> There has to be a better way to write this logic.. >> >> [...] >> >>> + >>> +static const struct of_device_id icss_iep_of_match[]; >>> + >> >> Why the forward declaration? > > I will remove this, I don't see any reason for this. > >> >>> +static int icss_iep_probe(struct platform_device *pdev) >>> +{ >>> + struct device *dev = &pdev->dev; >>> + struct icss_iep *iep; >>> + struct clk *iep_clk; >>> + >>> + iep = devm_kzalloc(dev, sizeof(*iep), GFP_KERNEL); >>> + if (!iep) >>> + return -ENOMEM; >>> + >>> + iep->dev = dev; >>> + iep->base = devm_platform_ioremap_resource(pdev, 0); >>> + if (IS_ERR(iep->base)) >>> + return -ENODEV; >>> + >>> + iep_clk = devm_clk_get(dev, NULL); >>> + if (IS_ERR(iep_clk)) >>> + return PTR_ERR(iep_clk); >>> + >>> + iep->refclk_freq = clk_get_rate(iep_clk); >>> + >>> + iep->def_inc = NSEC_PER_SEC / iep->refclk_freq; /* ns per clock tick */ >>> + if (iep->def_inc > IEP_MAX_DEF_INC) { >>> + dev_err(dev, "Failed to set def_inc %d. IEP_clock is too slow to be >>> supported\n", >>> + iep->def_inc); >>> + return -EINVAL; >>> + } >>> + >>> + iep->plat_data = of_device_get_match_data(dev); >> >> Directly using of_*() functions is often wrong, try just device_get_match_data(). >> > > Sure. I will change to device_get_match_data(). > >> [...] >> >>> +static struct platform_driver icss_iep_driver = { >>> + .driver = { >>> + .name = "icss-iep", >>> + .of_match_table = of_match_ptr(icss_iep_of_match), >> >> This driver cannot work without OF, using of_match_ptr() is not needed. >> > > Sure, I will drop of_match_ptr(). > >> Andrew > > > For reading and updating registers, we can have > 1. icss_iep_readl / writel and regmap_update_bits() OR > 2. regmap_read / write and regmap_update_bits() OR > 3. icss_iep_readl / writel and regmap_fields OR > 4. regmap_read / write and regmap_fields > > > Currently we are using 1. Please let me know if you are fine with this and I > can continue using 1. If not, please let me know your recommendation out of this 4. > > [1] > https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/commit/?h=linux-5.10.y&id=f4f45bf71cad5be232536d63a0557d13a7eed162 >
Powered by blists - more mailing lists