| Message ID | 20230901131502.1549809-1-quic_omprsing@quicinc.com |
|---|---|
| State | New |
| Headers | show |
| Series | crypto: qcom-rng: Add hwrng support | expand |
On 9/1/2023 8:16 PM, Bjorn Andersson wrote: > On Fri, Sep 01, 2023 at 06:45:02PM +0530, Om Prakash Singh wrote: >> This is follow patch on top of [1] > > This information does not add value to the git history, if you need to > inform the maintainer that the patch should be applied after some > in-flight dependency then state so after the "---" line below. > > But, this patch strictly conflicts with [1], so the statement won't make > sense if this is merged. > >> to add hwrng support for newer platform with trng capability. > > Please rewrite this so that it's clear that the problem you're trying to > solve with this patch (i.e. the problem description) is that newer > platforms has trng. Describe how this relates to the existing driver > (e.g. same/similar hardware interface). State that you purposefully kept > the crypto interface in place for the new hardware as well (so that it's > clear that this isn't an accident or oversight). > >> >> [1] https://lore.kernel.org/lkml/20230824-topic-sm8550-rng-v2-4-dfcafbb16a3e@linaro.org/ >> >> Signed-off-by: Om Prakash Singh <quic_omprsing@quicinc.com> >> --- >> drivers/crypto/qcom-rng.c | 72 ++++++++++++++++++++++++++++++++++----- >> 1 file changed, 63 insertions(+), 9 deletions(-) >> >> diff --git a/drivers/crypto/qcom-rng.c b/drivers/crypto/qcom-rng.c >> index fb54b8cfc35f..f78ffdcc66ec 100644 >> --- a/drivers/crypto/qcom-rng.c >> +++ b/drivers/crypto/qcom-rng.c >> @@ -13,6 +13,7 @@ >> #include <linux/module.h> >> #include <linux/of.h> >> #include <linux/platform_device.h> >> +#include <linux/hw_random.h> > > Please keep these sorted, alphabetically. > >> >> /* Device specific register offsets */ >> #define PRNG_DATA_OUT 0x0000 >> @@ -32,13 +33,18 @@ struct qcom_rng { >> struct mutex lock; >> void __iomem *base; >> struct clk *clk; >> - unsigned int skip_init; >> + struct qcom_rng_of_data *of_data; >> }; >> >> struct qcom_rng_ctx { >> struct qcom_rng *rng; >> }; >> >> +struct qcom_rng_of_data { >> + bool skip_init; >> + bool hwrng_support; >> +}; >> + >> static struct qcom_rng *qcom_rng_dev; >> >> static int qcom_rng_read(struct qcom_rng *rng, u8 *data, unsigned int max) >> @@ -70,7 +76,7 @@ static int qcom_rng_read(struct qcom_rng *rng, u8 *data, unsigned int max) >> } >> } while (currsize < max); >> >> - return 0; >> + return currsize; >> } >> >> static int qcom_rng_generate(struct crypto_rng *tfm, >> @@ -79,7 +85,8 @@ static int qcom_rng_generate(struct crypto_rng *tfm, >> { >> struct qcom_rng_ctx *ctx = crypto_rng_ctx(tfm); >> struct qcom_rng *rng = ctx->rng; >> - int ret; >> + int ret = -EFAULT; > > This initialization is useless, the very first thing you do with ret is > to overwrite it with the return value of clk_prepare_enable(). > >> + int read_size = 0; > > Similarly, the first use of this variable is an assignment. And "ret" > was a good, short, variable name. > >> >> ret = clk_prepare_enable(rng->clk); >> if (ret) >> @@ -87,11 +94,14 @@ static int qcom_rng_generate(struct crypto_rng *tfm, >> >> mutex_lock(&rng->lock); >> >> - ret = qcom_rng_read(rng, dstn, dlen); >> + read_size = qcom_rng_read(rng, dstn, dlen); >> >> mutex_unlock(&rng->lock); >> clk_disable_unprepare(rng->clk); >> >> + if (read_size == dlen) > > This function used to return < 0 if qcom_rng_read() returned an error, > and 0 in all other cases. > > Now you will pass through negative values, you will return 0 if the loop > in qcom_rng_read() reached "dlen" ("max)", and you will return some > positive number if the break condition in the loop hit. > > In other words, this is wrong. > >> + ret = 0; >> + >> return ret; >> } >> >> @@ -101,6 +111,16 @@ static int qcom_rng_seed(struct crypto_rng *tfm, const u8 *seed, >> return 0; >> } >> >> +static int qcom_hwrng_read(struct hwrng *rng, void *data, size_t max, bool wait) >> +{ >> + int ret; >> + struct qcom_rng *qrng; >> + >> + qrng = (struct qcom_rng *)rng->priv; >> + ret = qcom_rng_read(qrng, data, max); >> + return ret; > > Initialize qrng directly when you define it, drop ret and just return > qcom_rng_read() directly. > >> +} >> + >> static int qcom_rng_enable(struct qcom_rng *rng) >> { >> u32 val; >> @@ -136,7 +156,7 @@ static int qcom_rng_init(struct crypto_tfm *tfm) >> >> ctx->rng = qcom_rng_dev; >> >> - if (!ctx->rng->skip_init) >> + if (!ctx->rng->of_data->skip_init) >> return qcom_rng_enable(ctx->rng); >> >> return 0; >> @@ -157,9 +177,16 @@ static struct rng_alg qcom_rng_alg = { >> } >> }; >> >> +static struct hwrng qcom_hwrng = { >> + .name = "qcom-hwrng", >> + .read = qcom_hwrng_read, >> + .quality = 1024, >> +}; >> + >> static int qcom_rng_probe(struct platform_device *pdev) >> { >> struct qcom_rng *rng; >> + const struct qcom_rng_of_data *data; > > Move this one line up, so we maintain the reverse xmas tree. > >> int ret; >> >> rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL); >> @@ -177,7 +204,8 @@ static int qcom_rng_probe(struct platform_device *pdev) >> if (IS_ERR(rng->clk)) >> return PTR_ERR(rng->clk); >> >> - rng->skip_init = (unsigned long)device_get_match_data(&pdev->dev); >> + data = of_device_get_match_data(&pdev->dev); >> + rng->of_data = (struct qcom_rng_of_data *)data; > > Why didn't you assign rng->of_data directly? > > Also, of_device_get_match_data() returns a void *, so you should have to > explicitly cast this. > >> >> qcom_rng_dev = rng; >> ret = crypto_register_rng(&qcom_rng_alg); >> @@ -185,6 +213,14 @@ static int qcom_rng_probe(struct platform_device *pdev) >> dev_err(&pdev->dev, "Register crypto rng failed: %d\n", ret); >> qcom_rng_dev = NULL; >> } > > Would be nice with a newline here, to get some separation between the > "paragraphs". > >> + if (rng->of_data->hwrng_support) { >> + qcom_hwrng.priv = (unsigned long)qcom_rng_dev; >> + ret = hwrng_register(&qcom_hwrng); >> + if (ret) { >> + dev_err(&pdev->dev, "Register hwrng failed: %d\n", ret); >> + qcom_rng_dev = NULL; > > You're leaving the rng registered with crypto here. Not sure if that > will result in a use after free, or just a NULL pointer dereference - > but it's not good either way. > >> + } >> + } >> >> return ret; >> } >> @@ -193,11 +229,29 @@ static int qcom_rng_remove(struct platform_device *pdev) >> { >> crypto_unregister_rng(&qcom_rng_alg); >> >> + if (qcom_rng_dev->of_data->hwrng_support) >> + hwrng_unregister(&qcom_hwrng); > > Why not use devm_hwrng_register() above instead? Then you wouldn't have > to unregister it here. > >> + >> qcom_rng_dev = NULL; >> >> return 0; >> } >> >> +struct qcom_rng_of_data qcom_prng_of_data = { >> + .skip_init = false, >> + .hwrng_support = false, >> +}; >> + >> +struct qcom_rng_of_data qcom_prng_ee_of_data = { >> + .skip_init = true, >> + .hwrng_support = false, >> +}; >> + >> +struct qcom_rng_of_data qcom_trng_of_data = { >> + .skip_init = true, > > Can you please confirm that it's appropriate to name this "trng" without > the "-ee" suffix. Should all trng instances (v2 and v3) skip > initialization? All trng supported platform needs to skip initialzation. we don't need to have both "trng-ee" and "trng". If "trng-ee" is prefer we shold update it in patch [1] it itself, > >> + .hwrng_support = true, >> +}; >> + >> static const struct acpi_device_id __maybe_unused qcom_rng_acpi_match[] = { >> { .id = "QCOM8160", .driver_data = 1 }, >> {} >> @@ -205,9 +259,9 @@ static const struct acpi_device_id __maybe_unused qcom_rng_acpi_match[] = { >> MODULE_DEVICE_TABLE(acpi, qcom_rng_acpi_match); >> >> static const struct of_device_id __maybe_unused qcom_rng_of_match[] = { >> - { .compatible = "qcom,prng", .data = (void *)0}, >> - { .compatible = "qcom,prng-ee", .data = (void *)1}, >> - { .compatible = "qcom,trng", .data = (void *)1}, >> + { .compatible = "qcom,prng", .data = &qcom_prng_of_data }, >> + { .compatible = "qcom,prng-ee", .data = &qcom_prng_ee_of_data }, >> + { .compatible = "qcom,trng", .data = &qcom_trng_of_data }, > > So, should this be qcom,trng or qcom,trng-ee? > > > Where is your devicetree binding patch? DT binding patch is submitted by Neil [1] I will address all other review comments in next patch version. [1] https://lore.kernel.org/lkml/20230824-topic-sm8550-rng-v2-4-dfcafbb16a3e@linaro.org/ > > Regards, > Bjorn
On 5.09.2023 04:50, Om Prakash Singh wrote: > > > On 9/1/2023 8:16 PM, Bjorn Andersson wrote: >> On Fri, Sep 01, 2023 at 06:45:02PM +0530, Om Prakash Singh wrote: >>> This is follow patch on top of [1] >> >> This information does not add value to the git history, if you need to >> inform the maintainer that the patch should be applied after some >> in-flight dependency then state so after the "---" line below. >> >> But, this patch strictly conflicts with [1], so the statement won't make >> sense if this is merged. >> >>> to add hwrng support for newer platform with trng capability. >> >> Please rewrite this so that it's clear that the problem you're trying to >> solve with this patch (i.e. the problem description) is that newer >> platforms has trng. Describe how this relates to the existing driver >> (e.g. same/similar hardware interface). State that you purposefully kept >> the crypto interface in place for the new hardware as well (so that it's >> clear that this isn't an accident or oversight). >> >>> >>> [1] https://lore.kernel.org/lkml/20230824-topic-sm8550-rng-v2-4-dfcafbb16a3e@linaro.org/ >>> >>> Signed-off-by: Om Prakash Singh <quic_omprsing@quicinc.com> >>> --- [...] >> >> Can you please confirm that it's appropriate to name this "trng" without >> the "-ee" suffix. Should all trng instances (v2 and v3) skip >> initialization? > All trng supported platform needs to skip initialzation. > we don't need to have both "trng-ee" and "trng". > If "trng-ee" is prefer we shold update it in patch [1] it itself, Looking back at ba3ab6371cdd ("crypto: qcom-rng - Add support for prng-ee"), it was solved in a way that we would stray from today - nowadays we'd call it qcom,msm8996-prng or something. The -ee part was only there to discern parts that were initialized by other software. Since you said that all TRNGs need that, I'm also for dropping "-ee". Konrad
diff --git a/drivers/crypto/qcom-rng.c b/drivers/crypto/qcom-rng.c index fb54b8cfc35f..f78ffdcc66ec 100644 --- a/drivers/crypto/qcom-rng.c +++ b/drivers/crypto/qcom-rng.c @@ -13,6 +13,7 @@ #include <linux/module.h> #include <linux/of.h> #include <linux/platform_device.h> +#include <linux/hw_random.h> /* Device specific register offsets */ #define PRNG_DATA_OUT 0x0000 @@ -32,13 +33,18 @@ struct qcom_rng { struct mutex lock; void __iomem *base; struct clk *clk; - unsigned int skip_init; + struct qcom_rng_of_data *of_data; }; struct qcom_rng_ctx { struct qcom_rng *rng; }; +struct qcom_rng_of_data { + bool skip_init; + bool hwrng_support; +}; + static struct qcom_rng *qcom_rng_dev; static int qcom_rng_read(struct qcom_rng *rng, u8 *data, unsigned int max) @@ -70,7 +76,7 @@ static int qcom_rng_read(struct qcom_rng *rng, u8 *data, unsigned int max) } } while (currsize < max); - return 0; + return currsize; } static int qcom_rng_generate(struct crypto_rng *tfm, @@ -79,7 +85,8 @@ static int qcom_rng_generate(struct crypto_rng *tfm, { struct qcom_rng_ctx *ctx = crypto_rng_ctx(tfm); struct qcom_rng *rng = ctx->rng; - int ret; + int ret = -EFAULT; + int read_size = 0; ret = clk_prepare_enable(rng->clk); if (ret) @@ -87,11 +94,14 @@ static int qcom_rng_generate(struct crypto_rng *tfm, mutex_lock(&rng->lock); - ret = qcom_rng_read(rng, dstn, dlen); + read_size = qcom_rng_read(rng, dstn, dlen); mutex_unlock(&rng->lock); clk_disable_unprepare(rng->clk); + if (read_size == dlen) + ret = 0; + return ret; } @@ -101,6 +111,16 @@ static int qcom_rng_seed(struct crypto_rng *tfm, const u8 *seed, return 0; } +static int qcom_hwrng_read(struct hwrng *rng, void *data, size_t max, bool wait) +{ + int ret; + struct qcom_rng *qrng; + + qrng = (struct qcom_rng *)rng->priv; + ret = qcom_rng_read(qrng, data, max); + return ret; +} + static int qcom_rng_enable(struct qcom_rng *rng) { u32 val; @@ -136,7 +156,7 @@ static int qcom_rng_init(struct crypto_tfm *tfm) ctx->rng = qcom_rng_dev; - if (!ctx->rng->skip_init) + if (!ctx->rng->of_data->skip_init) return qcom_rng_enable(ctx->rng); return 0; @@ -157,9 +177,16 @@ static struct rng_alg qcom_rng_alg = { } }; +static struct hwrng qcom_hwrng = { + .name = "qcom-hwrng", + .read = qcom_hwrng_read, + .quality = 1024, +}; + static int qcom_rng_probe(struct platform_device *pdev) { struct qcom_rng *rng; + const struct qcom_rng_of_data *data; int ret; rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL); @@ -177,7 +204,8 @@ static int qcom_rng_probe(struct platform_device *pdev) if (IS_ERR(rng->clk)) return PTR_ERR(rng->clk); - rng->skip_init = (unsigned long)device_get_match_data(&pdev->dev); + data = of_device_get_match_data(&pdev->dev); + rng->of_data = (struct qcom_rng_of_data *)data; qcom_rng_dev = rng; ret = crypto_register_rng(&qcom_rng_alg); @@ -185,6 +213,14 @@ static int qcom_rng_probe(struct platform_device *pdev) dev_err(&pdev->dev, "Register crypto rng failed: %d\n", ret); qcom_rng_dev = NULL; } + if (rng->of_data->hwrng_support) { + qcom_hwrng.priv = (unsigned long)qcom_rng_dev; + ret = hwrng_register(&qcom_hwrng); + if (ret) { + dev_err(&pdev->dev, "Register hwrng failed: %d\n", ret); + qcom_rng_dev = NULL; + } + } return ret; } @@ -193,11 +229,29 @@ static int qcom_rng_remove(struct platform_device *pdev) { crypto_unregister_rng(&qcom_rng_alg); + if (qcom_rng_dev->of_data->hwrng_support) + hwrng_unregister(&qcom_hwrng); + qcom_rng_dev = NULL; return 0; } +struct qcom_rng_of_data qcom_prng_of_data = { + .skip_init = false, + .hwrng_support = false, +}; + +struct qcom_rng_of_data qcom_prng_ee_of_data = { + .skip_init = true, + .hwrng_support = false, +}; + +struct qcom_rng_of_data qcom_trng_of_data = { + .skip_init = true, + .hwrng_support = true, +}; + static const struct acpi_device_id __maybe_unused qcom_rng_acpi_match[] = { { .id = "QCOM8160", .driver_data = 1 }, {} @@ -205,9 +259,9 @@ static const struct acpi_device_id __maybe_unused qcom_rng_acpi_match[] = { MODULE_DEVICE_TABLE(acpi, qcom_rng_acpi_match); static const struct of_device_id __maybe_unused qcom_rng_of_match[] = { - { .compatible = "qcom,prng", .data = (void *)0}, - { .compatible = "qcom,prng-ee", .data = (void *)1}, - { .compatible = "qcom,trng", .data = (void *)1}, + { .compatible = "qcom,prng", .data = &qcom_prng_of_data }, + { .compatible = "qcom,prng-ee", .data = &qcom_prng_ee_of_data }, + { .compatible = "qcom,trng", .data = &qcom_trng_of_data }, {} }; MODULE_DEVICE_TABLE(of, qcom_rng_of_match);
This is follow patch on top of [1] to add hwrng support for newer platform with trng capability. [1] https://lore.kernel.org/lkml/20230824-topic-sm8550-rng-v2-4-dfcafbb16a3e@linaro.org/ Signed-off-by: Om Prakash Singh <quic_omprsing@quicinc.com> --- drivers/crypto/qcom-rng.c | 72 ++++++++++++++++++++++++++++++++++----- 1 file changed, 63 insertions(+), 9 deletions(-)