Messages in this thread | | | Subject | Re: [RFC v1 2/3] drivers: nvmem: Add driver for QTI qfprom-efuse support | From | "Ravi Kumar Bokka (Temp)" <> | Date | Mon, 18 May 2020 16:09:40 +0530 |
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Hi Srinivas, Thanks for your feedback. Please find my inline-comments.
On 5/15/2020 4:39 PM, Srinivas Kandagatla wrote: > > > On 14/05/2020 13:26, Ravi Kumar Bokka (Temp) wrote: >> Hi Srinivas, >> Thanks for your feedback by giving review comments. Please find my >> inline comments. >> >> >> Regards, >> Ravi Kumar.B >> >> On 5/13/2020 6:50 PM, Srinivas Kandagatla wrote: >>> >>> >>> On 12/05/2020 19:17, Ravi Kumar Bokka wrote: >>>> This patch adds new driver for QTI qfprom-efuse controller. This >>>> driver can >>>> access the raw qfprom regions for fuse blowing. >>> >>> QTI? >> >> guidance I have received from internal Legal/LOST team is that the >> QCOM prefix needs to be changed to QTI everywhere it is used >> > > I dont mind this in comments or patch subject line but the valid vendor > prefix for Qualcomm is "qcom". >
I will maintain Qualcomm Technologies Inc(QTI) in the patch description and change Kconfig as suggested.
> >>> >>>> >>>> The current existed qfprom driver is only supports for cpufreq, >>>> thermal sensors >>>> drivers by read out calibration data, speed bins..etc which is stored >>>> by qfprom efuses. >>> >>> Can you explain bit more about this QFPROM instance, Is this QFPROM >>> part of secure controller address space? >>> Is this closely tied to SoC or Secure controller version? >>> >>> Any reason why this can not be integrated into qfprom driver with >>> specific compatible. >>> >> >> QFPROM driver communicates with sec_controller address space however >> scope and functionalities of this driver is different and not limited >> as existing qfprom fuse Read-Only driver for specific “fuse buckets’ >> like cpufreq, thermal sensors etc. QFPROM fuse write driver in this >> patch requires specific sequence to write/blow fuses unlike other >> driver. Scope/functionalities are different and this is separate driver. >> > > This is another variant of qfprom, so please add this support in the > existing qfprom driver, you could deal with the differences using > specific compatible within the driver. > > Doug already covered most of the comments, consider them as mandatory > requirements for upstreaming! > > --srini >
Based on the compatible, do i need to separate probe function for qfprom-efuse and maintain separate nvmem object to register nvmem framework. Is this what you are suggesting to implementing this in to one existing driver? Do I need to maintain separate efuse dt node?
Could you please suggest me to proceed further.
> >>>> >>>> Signed-off-by: Ravi Kumar Bokka <rbokka@codeaurora.org> >>>> --- >>>> drivers/nvmem/Kconfig | 10 + >>>> drivers/nvmem/Makefile | 2 + >>>> drivers/nvmem/qfprom-efuse.c | 476 >>>> +++++++++++++++++++++++++++++++++++++++++++ >>>> 3 files changed, 488 insertions(+) >>>> create mode 100644 drivers/nvmem/qfprom-efuse.c >>>> >>> ... >>> >>>> diff --git a/drivers/nvmem/qfprom-efuse.c >>>> b/drivers/nvmem/qfprom-efuse.c >>>> new file mode 100644 >>>> index 0000000..2e3c275 >>>> --- /dev/null >>>> +++ b/drivers/nvmem/qfprom-efuse.c >>>> @@ -0,0 +1,476 @@ >>>> +// SPDX-License-Identifier: GPL-2.0-only >>>> +/* >>>> + * Copyright (c) 2020, The Linux Foundation. All rights reserved. >>>> + */ >>>> + >>>> +#include <linux/clk.h> >>>> +#include <linux/device.h> >>>> +#include <linux/io.h> >>>> +#include <linux/iopoll.h> >>>> +#include <linux/kernel.h> >>>> +#include <linux/module.h> >>>> +#include <linux/mod_devicetable.h> >>>> +#include <linux/nvmem-provider.h> >>>> +#include <linux/of_device.h> >>>> +#include <linux/platform_device.h> >>>> +#include <linux/regulator/consumer.h> >>>> + >>>> +#define QFPROM_BLOW_STATUS_BUSY 0x1 >>>> +#define QFPROM_BLOW_STATUS_READY 0x0 >>>> + >>>> +/* Blow timer clock frequency in Mhz for 10nm LPe technology */ >>>> +#define QFPROM_BLOW_TIMER_OFFSET 0x03c >>>> +#define QFPROM_BLOW_TIMER_RESET_VALUE 0x0 >>>> + >>>> +/* Amount of time required to hold charge to blow fuse in >>>> micro-seconds */ >>>> +#define QFPROM_FUSE_BLOW_POLL_PERIOD 100 >>>> +#define QFPROM_BLOW_STATUS_OFFSET 0x048 >>>> + >>>> +#define QFPROM_ACCEL_OFFSET 0x044 >>>> + >>>> +/** >>>> + * struct qfprom_efuse_platform_data - structure holding qfprom-efuse >>>> + * platform data >>>> + * >>>> + * @name: qfprom-efuse compatible name >>> >>> ?? >> >> Thanks for your feedback. I will address this change >> >>>> + * @fuse_blow_time_in_us: Should contain the wait time when doing >>>> the fuse blow >>>> + * @accel_value: Should contain qfprom accel value >>>> + * @accel_reset_value: The reset value of qfprom accel value >>>> + * @qfprom_blow_timer_value: The timer value of qfprom when doing >>>> efuse blow >>>> + * @qfprom_blow_reset_freq: The frequency required to set when fuse >>>> blowing >>>> + * is done >>>> + * @qfprom_blow_set_freq: The frequency required to set when we >>>> start the >>>> + * fuse blowing >>>> + * @qfprom_max_vol: max voltage required to set fuse blow >>>> + * @qfprom_min_vol: min voltage required to set fuse blow >>> >>> How specific are these values per SoC? >>> >> >> This voltage level may change based on SoC and/or fuse-hardware >> technology, it would change for SoC with different technology, hence >> we have kept it in SOC specific settings. >> >>> >>>> + */ >>>> +struct qfprom_efuse_platform_data { >>>> + const char *name; >>>> + u8 fuse_blow_time_in_us; >>>> + u32 accel_value; >>>> + u32 accel_reset_value; >>>> + u32 qfprom_blow_timer_value; >>>> + u32 qfprom_blow_reset_freq; >>>> + u32 qfprom_blow_set_freq; >>>> + u32 qfprom_max_vol; >>>> + u32 qfprom_min_vol; >>>> +}; >>>> + >>>> +/** >>>> + * struct qfprom_efuse_priv - structure holding qfprom-efuse >>>> attributes >>>> + * >>>> + * @qfpbase: iomapped memory space for qfprom base >>>> + * @qfpraw: iomapped memory space for qfprom raw fuse region >>>> + * @qfpmap: iomapped memory space for qfprom fuse blow timer >>>> + >>>> + * @dev: qfprom device structure >>>> + * @secclk: clock supply >>>> + * @vcc: regulator supply >>>> + >>>> + * @qfpraw_start: qfprom raw fuse start region >>>> + * @qfpraw_end: qfprom raw fuse end region >>>> + * @qfprom_efuse_platform_data: qfprom platform data >>>> + */ >>>> +struct qfprom_efuse_priv { >>>> + void __iomem *qfpbase; >>>> + void __iomem *qfpraw; >>>> + void __iomem *qfpmap; >>> >>> Why are these memory regions split? Can't you just have complete >>> qfprom area and add fixed offset for qfpraw within the driver? >>> >> >> Thanks for your feedback. I will address this change. >> I have separated this memory regions because to identify raw fuse >> regions separately and compare these raw fuse regions from the user >> given input. >> >>>> + struct device *dev; >>>> + struct clk *secclk; >>>> + struct regulator *vcc; >>>> + resource_size_t qfpraw_start; >>>> + resource_size_t qfpraw_end; >>> Why do we need to check this range? as long as we set the >>> nvmem_config with correct range then you should not need this check. >>> >> >> There is no harm in this explicit check in QFPROM-fuse driver and >> based on internal review with our security team, this check is >> important to avoid dependency on other upper layer. >> >> >>> >>>> + struct qfprom_efuse_platform_data efuse; >>> A pointer here should be good enough? >>>> +}; >>>> + >>> >> >> Thanks for your feedback. I will address this change >> >>> ... >>> >>>> +/* >>>> + * sets the value of the blow timer, accel register and the clock >>>> + * and voltage settings >>>> + */ >>>> +static int qfprom_enable_fuse_blowing(const struct >>>> qfprom_efuse_priv *priv) >>>> +{ >>>> + int ret; >>>> + >>>> + ret = qfprom_disable_fuse_blowing(priv); >>>> + if (ret) { >>>> + dev_err(priv->dev, "qfprom_disable_fuse_blowing()\n"); >>>> + return ret; >>>> + } >>> >>> Why do we need to qfprom_disable_fuse_blowing() for every call to >>> enable it? >>> >>> Or are we missing some error handling in the caller? >>> >> >> We must disable/vote-off this QFPROM fuse power rail after blowing >> fuse, it is the safe and right approach as per hardware programming >> guide for fuse blowing process. Caller here is user space, can’t >> control fuse-power-rail or can’t be relied to follow the required >> process. There could also be unnecessary risk of leaving the >> vote/power-rail configured at specific level after blowing the fuse. >> As per hardware requirement, right after fuse blowing, we need to >> disable power rail. >> >>>> + >>>> + writel(priv->efuse.qfprom_blow_timer_value, priv->qfpmap + >>>> + QFPROM_BLOW_TIMER_OFFSET); >>>> + writel(priv->efuse.accel_value, priv->qfpmap + >>>> QFPROM_ACCEL_OFFSET); >>>> + >>>> + ret = qfprom_set_clock_settings(priv); >>>> + if (ret) { >>>> + dev_err(priv->dev, "qpfrom_set_clock_settings()\n"); >>>> + return ret; >>>> + } >>>> + >>>> + ret = qfprom_set_voltage_settings(priv, >>>> priv->efuse.qfprom_min_vol, >>>> + priv->efuse.qfprom_max_vol); >>>> + if (ret) { >>>> + dev_err(priv->dev, "qfprom_set_voltage_settings()\n"); >>>> + return ret; >>>> + } >>>> + >>>> + return 0; >>>> +} >>>> + >>> >>> << >>>> +/* >>>> + * verifying to make sure address being written or read is from qfprom >>>> + * raw address range >>>> + */ >>>> +bool addr_in_qfprom_range(const struct qfprom_efuse_priv *priv, u32 >>>> reg, >>>> + size_t bytes) >>>> +{ >>>> + if (((reg + bytes) > reg) && (reg >= priv->qfpraw_start) && >>>> + ((reg + bytes) <= priv->qfpraw_end)) { >>>> + return 1; >>>> + } >>>> + >>>> + return 0; >>>> +} >>> >> >>> Above function is totally redundant, nvmem core already has checks >>> for this. >>> >> >> There is no harm in this explicit check in QFPROM-fuse driver and >> based on internal review with our security team, this check is >> important to avoid dependency on other upper layer. >> >>> >>> >>>> + >>>> +/* >>>> + * API for reading from raw qfprom region >>>> + */ >>>> +static int qfprom_efuse_reg_read(void *context, unsigned int reg, >>>> void *_val, >>>> + size_t bytes) >>>> +{ >>>> + struct qfprom_efuse_priv *priv = context; >>>> + u32 *value = _val; >>>> + u32 align_check; >>>> + int i = 0, words = bytes / 4; >>>> + >>>> + dev_info(priv->dev, >>>> + "reading raw qfprom region offset: 0x%08x of size: %zd\n", >>>> + reg, bytes); >>> >>> In general there is lot of debug info across the code, do you really >>> need all this? Consider removing these! >>> >> >> Thanks for your feedback. I will address this change. >> >>>> + >>>> + if (bytes % 4 != 0x00) { >>>> + dev_err(priv->dev, >>>> + "Bytes: %zd to read should be word align\n", >>>> + bytes); >>>> + return -EINVAL; >>>> + } >>> >>> This word align check is also redundant once you set nvmem_config >>> with correct word_size. >>> >> >> I understand that there may be different approach to handle this. We >> have used this approach and tested this driver thoroughly. Unless >> there is technical limitation, changing this word_size would end up >> requiring re-writing write/read APIs and going through testing again, >> there is not much difference in either approach, we would like to keep >> this approach unless there is technical concern. >> >>> >>>> + >>>> + if (!addr_in_qfprom_range(priv, reg, bytes)) { >>>> + dev_err(priv->dev, >>>> + "Invalid qfprom raw region offset 0x%08x & bytes %zd\n", >>>> + reg, bytes); >>>> + return -EINVAL; >>>> + } >>>> + >>>> + align_check = (reg & 0xF); >>>> + >>>> + if (((align_check & ~3) == align_check) && value != NULL) >>>> + while (words--) >>>> + *value++ = readl(priv->qfpbase + reg + (i++ * 4)); >>>> + >>>> + else >>>> + dev_err(priv->dev, >>>> + "Invalid input parameter 0x%08x fuse blow address\n", >>>> + reg); >>>> + >>>> + return 0; >>>> +} >>> ... >>> >>>> + >>>> +static int qfprom_efuse_probe(struct platform_device *pdev) >>>> +{ >>>> + struct device *dev = &pdev->dev; >>>> + struct resource *qfpbase, *qfpraw, *qfpmap; >>>> + struct nvmem_device *nvmem; >>>> + struct nvmem_config *econfig; >>>> + struct qfprom_efuse_priv *priv; >>>> + const struct qfprom_efuse_platform_data *drvdata; >>>> + int ret; >>>> + >>>> + dev_info(&pdev->dev, "[%s]: Invoked\n", __func__); >>>> + >>> >>> too much debug! >>> >> >> Thanks for your feedback. I will address this change. >> >>>> + drvdata = of_device_get_match_data(&pdev->dev); >>>> + if (!drvdata) >>>> + return -EINVAL; >>> Unnecessary check as this driver will not be probed unless there is a >>> compatible match. >>> >> >> Thanks for your feedback. I will address this change. >> >>> >>>> + >>>> + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); >>>> + if (!priv) >>>> + return -ENOMEM; >>>> + >>>> + priv->efuse.fuse_blow_time_in_us = drvdata->fuse_blow_time_in_us; >>>> + priv->efuse.accel_value = drvdata->accel_value; >>>> + priv->efuse.accel_reset_value = drvdata->accel_reset_value; >>>> + priv->efuse.qfprom_blow_timer_value = >>>> drvdata->qfprom_blow_timer_value; >>>> + priv->efuse.qfprom_blow_reset_freq = >>>> drvdata->qfprom_blow_reset_freq; >>>> + priv->efuse.qfprom_blow_set_freq = drvdata->qfprom_blow_set_freq; >>>> + priv->efuse.qfprom_max_vol = drvdata->qfprom_max_vol; >>>> + priv->efuse.qfprom_min_vol = drvdata->qfprom_min_vol; >>>> + priv->dev = dev; >>>> + >>>> + qfpbase = platform_get_resource(pdev, IORESOURCE_MEM, 0); >>>> + >>>> + priv->qfpbase = devm_ioremap_resource(dev, qfpbase); >>>> + if (IS_ERR(priv->qfpbase)) { >>>> + ret = PTR_ERR(priv->qfpbase); >>>> + goto err; >>>> + } >>>> + >>>> + qfpraw = platform_get_resource(pdev, IORESOURCE_MEM, 1); >>>> + >>>> + priv->qfpraw = devm_ioremap_resource(dev, qfpraw); >>>> + if (IS_ERR(priv->qfpraw)) { >>>> + ret = PTR_ERR(priv->qfpraw); >>>> + goto err; >>>> + } >>>> + >>>> + priv->qfpraw_start = qfpraw->start - qfpbase->start; >>>> + priv->qfpraw_end = qfpraw->end - qfpbase->start; >>>> + >>>> + qfpmap = platform_get_resource(pdev, IORESOURCE_MEM, 2); >>>> + >>>> + priv->qfpmap = devm_ioremap_resource(dev, qfpmap); >>>> + if (IS_ERR(priv->qfpmap)) { >>>> + ret = PTR_ERR(priv->qfpmap); >>>> + goto err; >>>> + } >>>> + >>>> + priv->vcc = devm_regulator_get(&pdev->dev, "vcc"); >>> >>> I see no reference to this regulator in dt bindings. >> >> This perameter kept in board specific file i.e., sc7180-idp.dts file >> >>>> + if (IS_ERR(priv->vcc)) { >>>> + ret = PTR_ERR(priv->vcc); >>>> + if (ret == -ENODEV) >>>> + ret = -EPROBE_DEFER; >>> Can you explain what is going on here? >>> >> >> As i took other drivers reference, i have kept this check. >> >>>> + >>>> + goto err; >>>> + } >>>> + >>>> + priv->secclk = devm_clk_get(dev, "secclk"); >>>> + if (IS_ERR(priv->secclk)) { >>>> + ret = PTR_ERR(priv->secclk); >>>> + if (ret != -EPROBE_DEFER) >>>> + dev_err(dev, "secclk error getting : %d\n", ret); >>>> + goto err; >>>> + } >>>> + >>>> + ret = clk_prepare_enable(priv->secclk); >>>> + if (ret) { >>>> + dev_err(dev, "clk_prepare_enable() failed\n"); >>>> + goto err; >>>> + } >>>> + >>>> + econfig = devm_kzalloc(dev, sizeof(*econfig), GFP_KERNEL); >>>> + if (!econfig) >>> Why not disabling the clk here? >>>> + return -ENOMEM; >>> >> >> Thanks for your feedback. I will address this change. >> >>>> + >>>> + econfig->dev = dev; >>>> + econfig->name = "qfprom-efuse"; >>>> + econfig->stride = 1; >>>> + econfig->word_size = 1; >>>> + econfig->reg_read = qfprom_efuse_reg_read; >>>> + econfig->reg_write = qfprom_efuse_reg_write; >>>> + econfig->size = resource_size(qfpraw); >>>> + econfig->priv = priv; >>>> + >>>> + nvmem = devm_nvmem_register(dev, econfig); >>>> + >>>> + return PTR_ERR_OR_ZERO(nvmem); >>> probably you should check the nvmem here before returning to disable >>> the clk properly. >>> >> >> Thanks for your feedback. I will address this change. >> >>>> + >>>> +err: >>>> + clk_disable_unprepare(priv->secclk); >>>> + return ret; >>>> +} >>>> + >>>> +static const struct qfprom_efuse_platform_data >>>> sc7180_qfp_efuse_data = { >>>> + .name = "sc7180-qfprom-efuse", >>> Redundant. >>> >> >> Thanks for your feedback. I will address this change. >> >>>> + .fuse_blow_time_in_us = 10, >>>> + .accel_value = 0xD10, >>>> + .accel_reset_value = 0x800, >>>> + .qfprom_blow_timer_value = 25, >>>> + .qfprom_blow_reset_freq = 19200000, >>>> + .qfprom_blow_set_freq = 4800000, >>>> + .qfprom_max_vol = 1904000, >>>> + .qfprom_min_vol = 1800000, >>>> +}; >>>> + >>>> +static const struct of_device_id qfprom_efuse_of_match[] = { >>>> + { >>>> + .compatible = "qcom,sc7180-qfprom-efuse", >>>> + .data = &sc7180_qfp_efuse_data >>>> + }, >>>> + {/* sentinel */}, >>>> +}; >>>> + >>>> +MODULE_DEVICE_TABLE(of, qfprom_efuse_of_match); >>>> + >>>> +static struct platform_driver qfprom_efuse_driver = { >>>> + .probe = qfprom_efuse_probe, >>>> + .driver = { >>>> + .name = "sc7180-qfprom-efuse", >>>> + .of_match_table = qfprom_efuse_of_match, >>>> + }, >>>> +}; >>>> + >>>> +module_platform_driver(qfprom_efuse_driver); >>>> +MODULE_DESCRIPTION("QTI QFPROM Efuse driver"); >>>> +MODULE_LICENSE("GPL v2"); >>>> >>
Regards, Ravi Kumar.B
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