From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 87179C433B4 for ; Thu, 1 Apr 2021 07:08:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5073D60FE9 for ; Thu, 1 Apr 2021 07:08:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233371AbhDAHHr (ORCPT ); Thu, 1 Apr 2021 03:07:47 -0400 Received: from mail.kernel.org ([198.145.29.99]:48646 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233283AbhDAHHh (ORCPT ); Thu, 1 Apr 2021 03:07:37 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 0A6C26100A; Thu, 1 Apr 2021 07:07:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1617260856; bh=bVl57d/4fiyUdavdBfO/VSp+JHKCZiAnocwkVoIMVDI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=WDKj2DSpEzRN15lhYNujT6MLgz+lAhTPmbYQL/gQ9HvrWDCZsNIaXc10i1iM6kwPu lVIZdIkzxU19G8GuvpGiTlak0W2qU6fO1J5psT96i4Tq6klhfZJHI+M+Iu2r49jo/q Sbkc4PrOV+x6wsh/IUcTHqtGiKesGQEFXsedvxREgu+BtKaTeGw623LU1w/q4lUzhe RqMLJ/OHfxG8i8/HXdYnaIQEC3uvOABTD3hLwfVMh6GgxQa183RVQdIvCnWrWyDrDG UYvuEPuxhYCyEBqoNxdmdYCCX+DdyYC515m+bd9RHtnNKQEoejKG2CQp6IrOlYV+Ju j8tbEDYwYjykA== Date: Thu, 1 Apr 2021 12:37:32 +0530 From: Vinod Koul To: Srinivas Kandagatla Cc: yung-chuan.liao@linux.intel.com, pierre-louis.bossart@linux.intel.com, sanyog.r.kale@intel.com, alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org, robh@kernel.org, devicetree@vger.kernel.org Subject: Re: [PATCH] soundwire: qcom: wait for fifo space to be available before read/write Message-ID: References: <20210331170033.17174-1-srinivas.kandagatla@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210331170033.17174-1-srinivas.kandagatla@linaro.org> Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On 31-03-21, 18:00, Srinivas Kandagatla wrote: > If we write registers very fast we can endup in a situation where some > of the writes will be dropped without any notice. > > So wait for the fifo space to be available before reading/writing the > soundwire registers. > > Signed-off-by: Srinivas Kandagatla > --- > drivers/soundwire/qcom.c | 74 ++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 74 insertions(+) > > diff --git a/drivers/soundwire/qcom.c b/drivers/soundwire/qcom.c > index 6affa3cd4039..9b45717577f2 100644 > --- a/drivers/soundwire/qcom.c > +++ b/drivers/soundwire/qcom.c > @@ -24,6 +24,8 @@ > #define SWRM_COMP_CFG_IRQ_LEVEL_OR_PULSE_MSK BIT(1) > #define SWRM_COMP_CFG_ENABLE_MSK BIT(0) > #define SWRM_COMP_PARAMS 0x100 > +#define SWRM_COMP_PARAMS_WR_FIFO_DEPTH GENMASK(14, 10) > +#define SWRM_COMP_PARAMS_RD_FIFO_DEPTH GENMASK(19, 15) > #define SWRM_COMP_PARAMS_DOUT_PORTS_MASK GENMASK(4, 0) > #define SWRM_COMP_PARAMS_DIN_PORTS_MASK GENMASK(9, 5) > #define SWRM_INTERRUPT_STATUS 0x200 > @@ -51,6 +53,8 @@ > #define SWRM_CMD_FIFO_CMD 0x308 > #define SWRM_CMD_FIFO_FLUSH 0x1 > #define SWRM_CMD_FIFO_STATUS 0x30C > +#define SWRM_RD_CMD_FIFO_CNT_MASK GENMASK(20, 16) > +#define SWRM_WR_CMD_FIFO_CNT_MASK GENMASK(12, 8) > #define SWRM_CMD_FIFO_CFG_ADDR 0x314 > #define SWRM_CONTINUE_EXEC_ON_CMD_IGNORE BIT(31) > #define SWRM_RD_WR_CMD_RETRIES 0x7 > @@ -104,6 +108,7 @@ > #define SWR_BROADCAST_CMD_ID 0x0F > #define SWR_MAX_CMD_ID 14 > #define MAX_FIFO_RD_RETRY 3 > +#define SWR_OVERFLOW_RETRY_COUNT 30 > > struct qcom_swrm_port_config { > u8 si; > @@ -147,6 +152,8 @@ struct qcom_swrm_ctrl { > int (*reg_read)(struct qcom_swrm_ctrl *ctrl, int reg, u32 *val); > int (*reg_write)(struct qcom_swrm_ctrl *ctrl, int reg, int val); > u32 slave_status; > + u32 wr_fifo_depth; > + u32 rd_fifo_depth; > }; > > struct qcom_swrm_data { > @@ -238,6 +245,63 @@ static u32 swrm_get_packed_reg_val(u8 *cmd_id, u8 cmd_data, > return val; > } > > +static int swrm_wait_for_rd_fifo_avail(struct qcom_swrm_ctrl *swrm) > +{ > + u32 fifo_outstanding_cmd, value; > + u8 fifo_retry_count = SWR_OVERFLOW_RETRY_COUNT; > + > + /* Check for fifo underflow during read */ > + swrm->reg_read(swrm, SWRM_CMD_FIFO_STATUS, &value); > + fifo_outstanding_cmd = FIELD_GET(SWRM_RD_CMD_FIFO_CNT_MASK, value); > + > + /* Check number of outstanding commands in fifo before read */ > + if (fifo_outstanding_cmd) > + return 0; > + > + do { > + usleep_range(500, 510); > + swrm->reg_read(swrm, SWRM_CMD_FIFO_STATUS, &value); > + fifo_outstanding_cmd = FIELD_GET(SWRM_RD_CMD_FIFO_CNT_MASK, value); > + if (fifo_outstanding_cmd > 0) > + break; > + } while (fifo_retry_count--); > + > + if (fifo_outstanding_cmd == 0) { > + dev_err_ratelimited(swrm->dev, "%s err read underflow\n", __func__); > + return -ENOMEM; ENOMEM ? that should be EIO, we expected data but didnt get it in read fifo > + } > + > + return 0; > +} > + > +static int swrm_wait_for_wr_fifo_avail(struct qcom_swrm_ctrl *swrm) > +{ > + u32 fifo_outstanding_cmd, value; > + u8 fifo_retry_count = SWR_OVERFLOW_RETRY_COUNT; > + > + /* Check for fifo overflow during write */ > + swrm->reg_read(swrm, SWRM_CMD_FIFO_STATUS, &value); > + fifo_outstanding_cmd = FIELD_GET(SWRM_WR_CMD_FIFO_CNT_MASK, value); > + > + /* Check number of outstanding commands in fifo before write */ > + if (fifo_outstanding_cmd != swrm->wr_fifo_depth) > + return 0; maybe the comment should say, check for space in write fifo? > + > + do { > + usleep_range(500, 510); > + swrm->reg_read(swrm, SWRM_CMD_FIFO_STATUS, &value); > + fifo_outstanding_cmd = FIELD_GET(SWRM_WR_CMD_FIFO_CNT_MASK, value); > + if (fifo_outstanding_cmd < swrm->wr_fifo_depth) > + break; > + } while (fifo_retry_count--); > + > + if (fifo_outstanding_cmd == swrm->wr_fifo_depth) { > + dev_err_ratelimited(swrm->dev, "%s err write overflow\n", __func__); > + return -ENOMEM; EIO or better error code here too -- ~Vinod