From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f169.google.com (mail-pf1-f169.google.com [209.85.210.169]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 27DF63128BE for ; Sun, 26 Apr 2026 09:18:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.169 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777195081; cv=none; b=LUFcA0rbKaLu8qGsL4dw9+UqxLAIOqLh2tjL2LEIJGdneZJHTn1hl3L77hAkNZKL6T7ZL/OIFNjkltkcB7es1pyIZ9rMqAzOgxS22FdLAULsn44gFx+wZnWgPzF9AUJk8lsqyfWb/+MAPumJ1HcB/uSNIlUW8oKxWIW3n7oET/E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777195081; c=relaxed/simple; bh=oEBXgj2AK10Nj+bseAhxv0IPtj/BYxJP8djzcBoJ6+Q=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=L31vIvP8OXrdUDVP38ZB4Ja8SRkS5t6qz+LBElJ7Zl0SpYOwzdRqvJlzJHaiHm1m+8FdcS3v581K/cnWVcCtkCMm2/f2tXOkru6Sa0ohD1H0PqtHmpPK7xfCJOcPnHtn2l+6JbD0qDmBwWs8jx1aZtM3tO4/U7Tyc/sz5G85DxY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=ohtXgHFR; arc=none smtp.client-ip=209.85.210.169 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="ohtXgHFR" Received: by mail-pf1-f169.google.com with SMTP id d2e1a72fcca58-82f8bf96b46so4442755b3a.2 for ; Sun, 26 Apr 2026 02:18:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1777195079; x=1777799879; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=n/+x1NdsI6gqAesdJtZv8kaE6DjjhQ2mtExUzBuE6l8=; b=ohtXgHFRbwpPksGJUW53C5wgbJxpbAJCAnSWoKIB1YSEVkC7FQ6p4wGvx6bJ7T4IDJ m/NJGD0dMPNvdBpfzYkIYVOmzQrTnhceXY2CQRlJvw9Bpv4XrnWXHdpOEc/QgZBhE1Nt pSsw/EDUFOVAHZsDwyHYYrBg1V36LKZrfCkHzmZZ0tAXEberb2dmX6XsnzRWaubriICH 9b8sAPYygMBx2SiWwSmBfwvKZjrig11ePnfFKNMrh6AmPLSXBurf6dNnr6ujHb1OZfLt evaNsApf4Sk6vi26WFEXvOe+y6j/59FwAtJQFsd08+jcZb3FogEV4ylXoXqdZwfzlPLZ uKzQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1777195079; x=1777799879; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=n/+x1NdsI6gqAesdJtZv8kaE6DjjhQ2mtExUzBuE6l8=; b=W1kf2D1ENPsprxdrhbOvZ30R1hlhVI5c2evVR3AJlKYGaRuTsHMhmtV5l2H5aAub52 EilMbYzNsw524gLsFKDmEd5BWNQ7UusoQDYFVAPjvSEOXp96OhH9iQzK+8JpUWxjuUrG 1P7UWd+AC+TUc10mqgtWGxZGvcTB672tafvI9/VxMqaMOxBGVzD6Y9S5L4O+ZPRzjsc9 T3sxS4/WWZI05QqRnrSDm0as/49FqRMMC+YQUEQALFyTEQWs4TXCBc04qzm1KT4TyxZl fINJ3FPxdzcmNGWFIVhZbOUdo6FFLe87htgUAFdJjk25Xx03uGrJyZLeoD0ClYFq7bBT vJvw== X-Forwarded-Encrypted: i=1; AFNElJ87QmqLTWu2nOXAv6tQ0uJaiF4ecJVu9HscfGhvrZ6/cWEDQ86CnLhnNEpn9EpN0NTN/al+ibCglrA=@vger.kernel.org X-Gm-Message-State: AOJu0Yz6/ghjAto3D/uvByM1XDJKNWpaqm8y5pv0rAOCnP8KR2fIAIr9 0pE0pR+om5GqZlTJrA0l6H9Jsv8axEzYlFTXNtgT44Az4+mO05LjcKBk X-Gm-Gg: AeBDievSAe5q04JaPdYbOOjYOPagvc39QEm0TSszOuUcu8s1pSiQnsqO4PPLDjySZoq TWWhPDbzxYzuZjO5C06A9zWFDU/Surd3PsGgF1K91AmyZIuRQ/faelLJKsvzyoRrLzqIDIYxtNa VRvZ4eq1hMD7C16it/gfXqJwzj4My4SdNssEbK+T87cczVdBm3+wRfa/u8CYcaSpLLNikthBb8x JYobSdaOVbaPX29DymvZaaIP9M7gk/E2bE8JMELyhBjomEVje0s8NhmOvzKhqlz+a/0nMDJCyrQ 9C29V6KiIBE34sG/kmZJVgXd1Yh515V4BOB8KxqTA2mkEDmho3hjnDGmknypTJbTpiMMv1taUuW jWd057abUnsSQXb2zhBbBC8lquLJcqq0zSqBuyqqN0arknkKf9ayco6EEHpQKxyIKxb8zkb7tNX f/BVxxOdaCwRZ5gsacRLlY5KZ/Dq/Ori+wHXK6YjAECHlvrUmjmbgP8U0UuyU= X-Received: by 2002:a05:6a00:3492:b0:82f:1d38:f68d with SMTP id d2e1a72fcca58-82f8c8df5e1mr44757491b3a.34.1777195079480; Sun, 26 Apr 2026 02:17:59 -0700 (PDT) Received: from hu-ckantibh-hyd.qualcomm.com ([202.46.23.25]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-82f8e982fd3sm36145226b3a.10.2026.04.26.02.17.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 26 Apr 2026 02:17:59 -0700 (PDT) From: Sanjay Chitroda X-Google-Original-From: Sanjay Chitroda To: jic23@kernel.org Cc: dlechner@baylibre.com, nuno.sa@analog.com, andy@kernel.org, sanjayembeddedse@gmail.com, mingo@kernel.org, christophe.jaillet@wanadoo.fr, nabijaczleweli@nabijaczleweli.xyz, kees@kernel.org, kyungmin.park@samsung.com, k.wrona@samsung.com, linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v7 9/9] iio: ssp_sensors: reuse embedded RX buffer for SPI transfers Date: Sun, 26 Apr 2026 14:47:10 +0530 Message-Id: <20260426091710.3722035-10-sanjayembedded@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260426091710.3722035-1-sanjayembedded@gmail.com> References: <20260426091710.3722035-1-sanjayembedded@gmail.com> Precedence: bulk X-Mailing-List: linux-iio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Sanjay Chitroda Avoid allocating a temporary DMA buffer in the interrupt context when handling hub-to-AP and AP-to-hub SPI write messages. Replace the dynamically allocated RX buffer with a fixed-size, preallocated buffer embedded in the driver structure and reused for all SPI receive operations. This removes memory allocation from the IRQ path, simplifies lifetime management. Signed-off-by: Sanjay Chitroda --- Changes in v6: - Replace dynamically allocated RX buffer with embedded fixed-size buffer - Fix struct layout to satisfy DMA alignment constraints comment from David - v5 change: https://lore.kernel.org/all/20260406080852.2727453-6-sanjayembedded@gmail.com/ Changes in v5: - Rebase change on top of latest v5 patch series. Changes in v4: - Use preallocated buffer and stash a buffer that gets reused each time instead of a fresh allocation. - v3 change: https://lore.kernel.org/all/20260315125509.857195-3-sanjayembedded@gmail.com/ Changes in v3: - prepare series to have all respective cleanup API support for the ssp_sensors following input from Andy Shevchenko - v2 change: https://lore.kernel.org/all/20260311174151.3441429-1-sanjayembedded@gmail.com/ Changes in v2: - split series to individual patch - address review comment from Andy Shevchenko - v1 change: https://lore.kernel.org/all/20260310200513.2162018-3-sanjayembedded@gmail.com/ --- drivers/iio/common/ssp_sensors/ssp.h | 3 +++ drivers/iio/common/ssp_sensors/ssp_spi.c | 20 ++------------------ 2 files changed, 5 insertions(+), 18 deletions(-) diff --git a/drivers/iio/common/ssp_sensors/ssp.h b/drivers/iio/common/ssp_sensors/ssp.h index f649cdecc277..8295bb7062a3 100644 --- a/drivers/iio/common/ssp_sensors/ssp.h +++ b/drivers/iio/common/ssp_sensors/ssp.h @@ -174,6 +174,7 @@ struct ssp_sensorhub_info { * @pending_list: pending list for messages queued to be sent/read * @sensor_devs: registered IIO devices table * @enable_refcount: enable reference count for wdt (watchdog timer) + * @rx_buf: buffer to receive SPI data * @header_buffer: cache aligned buffer for packet header */ struct ssp_data { @@ -221,6 +222,8 @@ struct ssp_data { struct iio_dev *sensor_devs[SSP_SENSOR_MAX]; atomic_t enable_refcount; + u8 rx_buf[SSP_DATA_PACKET_SIZE]; + __le16 header_buffer[SSP_HEADER_BUFFER_SIZE / sizeof(__le16)] __aligned(IIO_DMA_MINALIGN); }; diff --git a/drivers/iio/common/ssp_sensors/ssp_spi.c b/drivers/iio/common/ssp_sensors/ssp_spi.c index 870214551f0b..e41da88bf96d 100644 --- a/drivers/iio/common/ssp_sensors/ssp_spi.c +++ b/drivers/iio/common/ssp_sensors/ssp_spi.c @@ -339,7 +339,7 @@ static int ssp_parse_dataframe(struct ssp_data *data, char *dataframe, int len) /* threaded irq */ int ssp_irq_msg(struct ssp_data *data) { - char *buffer; + char *buffer = data->rx_buf; u8 msg_type; int ret; u16 length, msg_options; @@ -383,19 +383,12 @@ int ssp_irq_msg(struct ssp_data *data) * but the slave should not send such ones - it is to * check but let's handle this */ - buffer = kmalloc(length, GFP_KERNEL | GFP_DMA); - if (!buffer) { - ret = -ENOMEM; - goto _unlock; - } /* got dead packet so it is always an error */ ret = spi_read(data->spi, buffer, length); if (ret >= 0) ret = -EPROTO; - kfree(buffer); - dev_err(SSP_DEV, "No match error %x\n", msg_options); @@ -428,22 +421,13 @@ int ssp_irq_msg(struct ssp_data *data) mutex_unlock(&data->pending_lock); break; case SSP_HUB2AP_WRITE: - buffer = kzalloc(length, GFP_KERNEL | GFP_DMA); - if (!buffer) - return -ENOMEM; - ret = spi_read(data->spi, buffer, length); if (ret < 0) { dev_err(SSP_DEV, "spi read fail\n"); - kfree(buffer); break; } - ret = ssp_parse_dataframe(data, buffer, length); - - kfree(buffer); - break; - + return ssp_parse_dataframe(data, buffer, length); default: dev_err(SSP_DEV, "unknown msg type\n"); return -EPROTO; -- 2.34.1