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Message-ID: <20200401201707.GG267644@minitux>
Date: Wed, 1 Apr 2020 13:17:07 -0700
From: Bjorn Andersson <bjorn.andersson@...aro.org>
To: Rishabh Bhatnagar <rishabhb@...eaurora.org>
Cc: linux-kernel@...r.kernel.org, linux-remoteproc@...r.kernel.org,
psodagud@...eaurora.org, tsoni@...eaurora.org,
sidgup@...eaurora.org
Subject: Re: [PATCH 1/2] remoteproc: qcom: Add bus scaling capability during
bootup
On Fri 27 Mar 17:59 PDT 2020, Rishabh Bhatnagar wrote:
> During bootup since remote processors cannot request for
> additional bus bandwidth from the interconect framework,
> platform driver should provide the proxy resources. This
> is useful for scenarios where the Q6 tries to access the DDR
> memory in the initial stages of bootup. For e.g. during
> bootup or after recovery modem Q6 tries to zero out the bss
> section in the DDR. Since this is a big chunk of memory if
> don't bump up the bandwidth we might encounter timeout issues.
> This patch makes a proxy vote for maximizing the bus bandwidth
> during bootup and removes it once processor is up.
>
> Signed-off-by: Rishabh Bhatnagar <rishabhb@...eaurora.org>
> ---
> drivers/remoteproc/qcom_q6v5_pas.c | 43 +++++++++++++++++++++++++++++++++++++-
> 1 file changed, 42 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/remoteproc/qcom_q6v5_pas.c b/drivers/remoteproc/qcom_q6v5_pas.c
> index edf9d0e..8f5db8d 100644
> --- a/drivers/remoteproc/qcom_q6v5_pas.c
> +++ b/drivers/remoteproc/qcom_q6v5_pas.c
> @@ -20,6 +20,7 @@
> #include <linux/qcom_scm.h>
> #include <linux/regulator/consumer.h>
> #include <linux/remoteproc.h>
> +#include <linux/interconnect.h>
These are sorted alphabetically, please maintain this.
> #include <linux/soc/qcom/mdt_loader.h>
> #include <linux/soc/qcom/smem.h>
> #include <linux/soc/qcom/smem_state.h>
> @@ -28,6 +29,9 @@
> #include "qcom_q6v5.h"
> #include "remoteproc_internal.h"
>
> +#define PIL_TZ_AVG_BW 0
> +#define PIL_TZ_PEAK_BW UINT_MAX
Please just inline these in do_bus_scaling().
> +
> struct adsp_data {
> int crash_reason_smem;
> const char *firmware_name;
> @@ -62,6 +66,7 @@ struct qcom_adsp {
> int proxy_pd_count;
>
> int pas_id;
> + struct icc_path *bus_client;
Please rename this proxy_path
> int crash_reason_smem;
> bool has_aggre2_clk;
>
> @@ -124,6 +129,25 @@ static int adsp_load(struct rproc *rproc, const struct firmware *fw)
>
> }
>
> +static int do_bus_scaling(struct qcom_adsp *adsp, bool enable)
adsp_bus_vote()
> +{
> + int rc;
This driver uses "int ret".
> + u32 avg_bw = enable ? PIL_TZ_AVG_BW : 0;
No need to carry a variable for 0 or 0, jut pass 0 in the function call
directly.
> + u32 peak_bw = enable ? PIL_TZ_PEAK_BW : 0;
> +
> + if (adsp->bus_client) {
No need for this check, icc_set_bw(NULL, ..) is a nop.
> + rc = icc_set_bw(adsp->bus_client, avg_bw, peak_bw);
> + if (rc) {
> + dev_err(adsp->dev, "bandwidth request failed(rc:%d)\n",
"failed to request bandwidth: %d\n"
> + rc);
> + return rc;
> + }
> + } else
> + dev_info(adsp->dev, "Bus scaling not setup for %s\n",
No need to print this.
> + adsp->rproc->name);
> + return 0;
> +}
> +
> static int adsp_start(struct rproc *rproc)
> {
> struct qcom_adsp *adsp = (struct qcom_adsp *)rproc->priv;
> @@ -131,9 +155,13 @@ static int adsp_start(struct rproc *rproc)
>
> qcom_q6v5_prepare(&adsp->q6v5);
>
> + ret = do_bus_scaling(adsp, true);
> + if (ret)
> + goto disable_irqs;
> +
> ret = adsp_pds_enable(adsp, adsp->active_pds, adsp->active_pd_count);
> if (ret < 0)
> - goto disable_irqs;
> + goto unscale_bus;
>
> ret = adsp_pds_enable(adsp, adsp->proxy_pds, adsp->proxy_pd_count);
> if (ret < 0)
> @@ -183,6 +211,8 @@ static int adsp_start(struct rproc *rproc)
> adsp_pds_disable(adsp, adsp->proxy_pds, adsp->proxy_pd_count);
> disable_active_pds:
> adsp_pds_disable(adsp, adsp->active_pds, adsp->active_pd_count);
> +unscale_bus:
> + do_bus_scaling(adsp, false);
> disable_irqs:
> qcom_q6v5_unprepare(&adsp->q6v5);
>
> @@ -198,6 +228,7 @@ static void qcom_pas_handover(struct qcom_q6v5 *q6v5)
> clk_disable_unprepare(adsp->aggre2_clk);
> clk_disable_unprepare(adsp->xo);
> adsp_pds_disable(adsp, adsp->proxy_pds, adsp->proxy_pd_count);
> + do_bus_scaling(adsp, false);
> }
>
> static int adsp_stop(struct rproc *rproc)
> @@ -280,6 +311,14 @@ static int adsp_init_regulator(struct qcom_adsp *adsp)
> return PTR_ERR_OR_ZERO(adsp->px_supply);
> }
>
> +static void adsp_init_bus_scaling(struct qcom_adsp *adsp)
> +{
> + adsp->bus_client = of_icc_get(adsp->dev, NULL);
> + if (!adsp->bus_client)
!adsp->bus_client means there's no interconnects property in the DT
node, you still need to test for errors with IS_ERR().
And in particular you're not guaranteed that the provider has probed, so
you need to propagate EPROBE_DEFER.
> + dev_warn(adsp->dev, "%s: unable to get bus client \n",
> + __func__);
This is a dev_err() for the case of IS_ERR().
And please drop the __func__, it doesn't add any value.
> +}
> +
> static int adsp_pds_attach(struct device *dev, struct device **devs,
> char **pd_names)
> {
> @@ -410,6 +449,8 @@ static int adsp_probe(struct platform_device *pdev)
> if (ret)
> goto free_rproc;
>
> + adsp_init_bus_scaling(adsp);
> +
As stated above, you need to propagate actual errors here (i.e. not the
case where of_icc_get() returned NULL, but when it returned IS_ERR())
Regards,
bjorn
> ret = adsp_pds_attach(&pdev->dev, adsp->active_pds,
> desc->active_pd_names);
> if (ret < 0)
> --
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
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