[PATCH v1 1/2] ath9k: fetch calibration data via nvmem subsystem

[PATCH v1 1/2] ath9k: fetch calibration data via nvmem subsystem

[Christian Lamparter]

On most embedded ath9k devices (like range extenders,
routers, accesspoints, ...) the calibration data is
stored in a MTD partitions named "ART", or "caldata"/
"calibration".

Since commit 4b361cfa8624 ("mtd: core: add OTP nvmem provider support"):
All MTD partitions are all automatically available through
the nvmem subsystem.

This feature - together with an nvmem cell definition either
in the platform data or via device-tree allows drivers to get
the data necessary for initializing the WIFI, without having
to wait around for the filesystem and userspace to do
the extractions.

Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
---
 drivers/net/wireless/ath/ath9k/eeprom.c | 12 +++++-
 drivers/net/wireless/ath/ath9k/hw.h     |  2 +
 drivers/net/wireless/ath/ath9k/init.c   | 56 +++++++++++++++++++++++++
 3 files changed, 69 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/ath/ath9k/eeprom.c b/drivers/net/wireless/ath/ath9k/eeprom.c
index c22d457dbc54..e6b3cd49ea18 100644
--- a/drivers/net/wireless/ath/ath9k/eeprom.c
+++ b/drivers/net/wireless/ath/ath9k/eeprom.c
@@ -135,13 +135,23 @@ static bool ath9k_hw_nvram_read_firmware(const struct firmware *eeprom_blob,
 					 offset, data);
 }
 
+static bool ath9k_hw_nvram_read_nvmem(struct ath_hw *ah, off_t offset,
+				      u16 *data)
+{
+	return ath9k_hw_nvram_read_array(ah->nvmem_blob,
+					 ah->nvmem_blob_len / sizeof(u16),
+					 offset, data);
+}
+
 bool ath9k_hw_nvram_read(struct ath_hw *ah, u32 off, u16 *data)
 {
 	struct ath_common *common = ath9k_hw_common(ah);
 	struct ath9k_platform_data *pdata = ah->dev->platform_data;
 	bool ret;
 
-	if (ah->eeprom_blob)
+	if (ah->nvmem_blob)
+		ret = ath9k_hw_nvram_read_nvmem(ah, off, data);
+	else if (ah->eeprom_blob)
 		ret = ath9k_hw_nvram_read_firmware(ah->eeprom_blob, off, data);
 	else if (pdata && !pdata->use_eeprom)
 		ret = ath9k_hw_nvram_read_pdata(pdata, off, data);
diff --git a/drivers/net/wireless/ath/ath9k/hw.h b/drivers/net/wireless/ath/ath9k/hw.h
index b7b65b1c90e8..096a206f49ed 100644
--- a/drivers/net/wireless/ath/ath9k/hw.h
+++ b/drivers/net/wireless/ath/ath9k/hw.h
@@ -977,6 +977,8 @@ struct ath_hw {
 	bool disable_5ghz;
 
 	const struct firmware *eeprom_blob;
+	u16 *nvmem_blob;	/* devres managed */
+	size_t nvmem_blob_len;
 
 	struct ath_dynack dynack;
 
diff --git a/drivers/net/wireless/ath/ath9k/init.c b/drivers/net/wireless/ath/ath9k/init.c
index e9a36dd7144f..1568730fc01e 100644
--- a/drivers/net/wireless/ath/ath9k/init.c
+++ b/drivers/net/wireless/ath/ath9k/init.c
@@ -22,6 +22,7 @@
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_net.h>
+#include <linux/nvmem-consumer.h>
 #include <linux/relay.h>
 #include <linux/dmi.h>
 #include <net/ieee80211_radiotap.h>
@@ -568,6 +569,57 @@ static void ath9k_eeprom_release(struct ath_softc *sc)
 	release_firmware(sc->sc_ah->eeprom_blob);
 }
 
+static int ath9k_nvmem_request_eeprom(struct ath_softc *sc)
+{
+	struct ath_hw *ah = sc->sc_ah;
+	struct nvmem_cell *cell;
+	void *buf;
+	size_t len;
+	int err;
+
+	cell = devm_nvmem_cell_get(sc->dev, "calibration");
+	if (IS_ERR(cell)) {
+		err = PTR_ERR(cell);
+
+		/* nvmem cell might not be defined, or the nvmem
+		 * subsystem isn't included. In this case, follow
+		 * the established "just return 0;" convention of
+		 * ath9k_init_platform to say:
+		 * "All good. Nothing to see here. Please go on."
+		 */
+		if (err == -ENOENT || err == -EOPNOTSUPP)
+			return 0;
+
+		return err;
+	}
+
+	buf = nvmem_cell_read(cell, &len);
+	if (IS_ERR(buf))
+		return PTR_ERR(buf);
+
+	/* run basic sanity checks on the returned nvram cell length.
+	 * That length has to be a multiple of a "u16" (i.e.: & 1).
+	 * Furthermore, it has to be more than "let's say" 512 bytes
+	 * but less than the maximum of AR9300_EEPROM_SIZE (16kb).
+	 */
+	if ((len & 1) == 1 || len < 512 || len >= AR9300_EEPROM_SIZE) {
+		kfree(buf);
+		return -EINVAL;
+	}
+
+	/* devres manages the calibration values release on shutdown */
+	ah->nvmem_blob = (u16 *)devm_kmemdup(sc->dev, buf, len, GFP_KERNEL);
+	kfree(buf);
+	if (IS_ERR(ah->nvmem_blob))
+		return PTR_ERR(ah->nvmem_blob);
+
+	ah->nvmem_blob_len = len;
+	ah->ah_flags &= ~AH_USE_EEPROM;
+	ah->ah_flags |= AH_NO_EEP_SWAP;
+
+	return 0;
+}
+
 static int ath9k_init_platform(struct ath_softc *sc)
 {
 	struct ath9k_platform_data *pdata = sc->dev->platform_data;
@@ -704,6 +756,10 @@ static int ath9k_init_softc(u16 devid, struct ath_softc *sc,
 	if (ret)
 		return ret;
 
+	ret = ath9k_nvmem_request_eeprom(sc);
+	if (ret)
+		return ret;
+
 	if (ath9k_led_active_high != -1)
 		ah->config.led_active_high = ath9k_led_active_high == 1;
 
-- 
2.33.0

[PATCH v1 2/2] ath9k: owl-loader: fetch pci init values through nvmem

[Christian Lamparter]

extends the owl loader to fetch important pci initialization
values - which are stored together with the calibration data -
through the nvmem subsystem.

This allows for much faster WIFI/ath9k initializations on devices
that do not require to perform any post-processing (like XOR'ing/
reversal or unpacking)... than the current way through the
firmware_request which involves the filesystem/userspace.

Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
---
 .../wireless/ath/ath9k/ath9k_pci_owl_loader.c | 105 +++++++++++++-----
 1 file changed, 76 insertions(+), 29 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/ath9k_pci_owl_loader.c b/drivers/net/wireless/ath/ath9k/ath9k_pci_owl_loader.c
index 56d1a7764b9f..708c8969b503 100644
--- a/drivers/net/wireless/ath/ath9k/ath9k_pci_owl_loader.c
+++ b/drivers/net/wireless/ath/ath9k/ath9k_pci_owl_loader.c
@@ -19,9 +19,14 @@
 #include <linux/delay.h>
 #include <linux/platform_device.h>
 #include <linux/ath9k_platform.h>
+#include <linux/nvmem-consumer.h>
+#include <linux/workqueue.h>
 
 struct owl_ctx {
+	struct pci_dev *pdev;
 	struct completion eeprom_load;
+	struct work_struct work;
+	struct nvmem_cell *cell;
 };
 
 #define EEPROM_FILENAME_LEN 100
@@ -42,6 +47,12 @@ static int ath9k_pci_fixup(struct pci_dev *pdev, const u16 *cal_data,
 	u32 bar0;
 	bool swap_needed = false;
 
+	/* also note that we are doing *u16 operations on the file */
+	if (cal_len > 4096 || cal_len < 0x200 || (cal_len & 1) == 1) {
+		dev_err(&pdev->dev, "eeprom has an invalid size.\n");
+		return -EINVAL;
+	}
+
 	if (*cal_data != AR5416_EEPROM_MAGIC) {
 		if (*cal_data != swab16(AR5416_EEPROM_MAGIC)) {
 			dev_err(&pdev->dev, "invalid calibration data\n");
@@ -99,38 +110,31 @@ static int ath9k_pci_fixup(struct pci_dev *pdev, const u16 *cal_data,
 	return 0;
 }
 
-static void owl_fw_cb(const struct firmware *fw, void *context)
+static void owl_rescan(struct pci_dev *pdev)
 {
-	struct pci_dev *pdev = (struct pci_dev *)context;
-	struct owl_ctx *ctx = (struct owl_ctx *)pci_get_drvdata(pdev);
-	struct pci_bus *bus;
-
-	complete(&ctx->eeprom_load);
-
-	if (!fw) {
-		dev_err(&pdev->dev, "no eeprom data received.\n");
-		goto release;
-	}
-
-	/* also note that we are doing *u16 operations on the file */
-	if (fw->size > 4096 || fw->size < 0x200 || (fw->size & 1) == 1) {
-		dev_err(&pdev->dev, "eeprom file has an invalid size.\n");
-		goto release;
-	}
-
-	if (ath9k_pci_fixup(pdev, (const u16 *)fw->data, fw->size))
-		goto release;
+	struct pci_bus *bus = pdev->bus;
 
 	pci_lock_rescan_remove();
-	bus = pdev->bus;
 	pci_stop_and_remove_bus_device(pdev);
 	/* the device should come back with the proper
 	 * ProductId. But we have to initiate a rescan.
 	 */
 	pci_rescan_bus(bus);
 	pci_unlock_rescan_remove();
+}
+
+static void owl_fw_cb(const struct firmware *fw, void *context)
+{
+	struct owl_ctx *ctx = (struct owl_ctx *)context;
+
+	complete(&ctx->eeprom_load);
 
-release:
+	if (fw) {
+		ath9k_pci_fixup(ctx->pdev, (const u16 *)fw->data, fw->size);
+		owl_rescan(ctx->pdev);
+	} else {
+		dev_err(&ctx->pdev->dev, "no eeprom data received.\n");
+	}
 	release_firmware(fw);
 }
 
@@ -152,6 +156,43 @@ static const char *owl_get_eeprom_name(struct pci_dev *pdev)
 	return eeprom_name;
 }
 
+static void owl_nvmem_work(struct work_struct *work)
+{
+	struct owl_ctx *ctx = container_of(work, struct owl_ctx, work);
+	void *buf;
+	size_t len;
+
+	complete(&ctx->eeprom_load);
+
+	buf = nvmem_cell_read(ctx->cell, &len);
+	if (!IS_ERR(buf)) {
+		ath9k_pci_fixup(ctx->pdev, buf, len);
+		kfree(buf);
+		owl_rescan(ctx->pdev);
+	} else {
+		dev_err(&ctx->pdev->dev, "no nvmem data received.\n");
+	}
+}
+
+static int owl_nvmem_probe(struct owl_ctx *ctx)
+{
+	int err;
+
+	ctx->cell = devm_nvmem_cell_get(&ctx->pdev->dev, "calibration");
+	if (IS_ERR(ctx->cell)) {
+		err = PTR_ERR(ctx->cell);
+		if (err == -ENOENT || err == -EOPNOTSUPP)
+			return 1; /* not present, try firmware_request */
+
+		return err;
+	}
+
+	INIT_WORK(&ctx->work, owl_nvmem_work);
+	schedule_work(&ctx->work);
+
+	return 0;
+}
+
 static int owl_probe(struct pci_dev *pdev,
 		     const struct pci_device_id *id)
 {
@@ -164,21 +205,27 @@ static int owl_probe(struct pci_dev *pdev,
 
 	pcim_pin_device(pdev);
 
-	eeprom_name = owl_get_eeprom_name(pdev);
-	if (!eeprom_name) {
-		dev_err(&pdev->dev, "no eeprom filename found.\n");
-		return -ENODEV;
-	}
-
 	ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
 	if (!ctx)
 		return -ENOMEM;
 
 	init_completion(&ctx->eeprom_load);
+	ctx->pdev = pdev;
 
 	pci_set_drvdata(pdev, ctx);
+
+	err = owl_nvmem_probe(ctx);
+	if (err <= 0)
+		return err;
+
+	eeprom_name = owl_get_eeprom_name(pdev);
+	if (!eeprom_name) {
+		dev_err(&pdev->dev, "no eeprom filename found.\n");
+		return -ENODEV;
+	}
+
 	err = request_firmware_nowait(THIS_MODULE, true, eeprom_name,
-				      &pdev->dev, GFP_KERNEL, pdev, owl_fw_cb);
+				      &pdev->dev, GFP_KERNEL, ctx, owl_fw_cb);
 	if (err)
 		dev_err(&pdev->dev, "failed to request caldata (%d).\n", err);
 
-- 
2.33.0

Re: [PATCH v1 1/2] ath9k: fetch calibration data via nvmem subsystem

[Kalle Valo]

Christian Lamparter <chunkeey@gmail.com> wrote:

> On most embedded ath9k devices (like range extenders,
> routers, accesspoints, ...) the calibration data is
> stored in a MTD partitions named "ART", or "caldata"/
> "calibration".
> 
> Since commit 4b361cfa8624 ("mtd: core: add OTP nvmem provider support"):
> All MTD partitions are all automatically available through
> the nvmem subsystem.
> 
> This feature - together with an nvmem cell definition either
> in the platform data or via device-tree allows drivers to get
> the data necessary for initializing the WIFI, without having
> to wait around for the filesystem and userspace to do
> the extractions.
> 
> Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
> Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

2 patches applied to ath-next branch of ath.git, thanks.

eb3a97a69be8 ath9k: fetch calibration data via nvmem subsystem
ef7bc2a76342 ath9k: owl-loader: fetch pci init values through nvmem

-- 
https://patchwork.kernel.org/project/linux-wireless/patch/f9b732b50a3453fadf3923cc75d365bae3505fe7.1630157099.git.chunkeey@gmail.com/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches