[1/3] fpga: xilinx-spi: extract a common driver core

Message ID 20240129225602.3832449-1-charles.perry@savoirfairelinux.com
State New
Headers
Series [1/3] fpga: xilinx-spi: extract a common driver core |

Commit Message

Charles Perry Jan. 29, 2024, 10:56 p.m. UTC
  Factor out the gpio handshaking (using PROGRAM_B, INIT_B and DONE)
protocol in xilinx-core so that it can be reused for another driver.
This commit does not change anything functionally to xilinx-spi.

xilinx-core expects drivers to provide two operations:

 * ->write(const char* buf, size_t count): write to the device
 * ->write_one_dummy_byte(): write 0xFF to the device

Signed-off-by: Charles Perry <charles.perry@savoirfairelinux.com>
---
 drivers/fpga/Kconfig       |   4 +
 drivers/fpga/Makefile      |   1 +
 drivers/fpga/xilinx-core.c | 210 +++++++++++++++++++++++++++++++++++++
 drivers/fpga/xilinx-core.h |  27 +++++
 drivers/fpga/xilinx-spi.c  | 202 +++--------------------------------
 5 files changed, 256 insertions(+), 188 deletions(-)
 create mode 100644 drivers/fpga/xilinx-core.c
 create mode 100644 drivers/fpga/xilinx-core.h
  

Comments

Rob Herring Feb. 2, 2024, 8:16 p.m. UTC | #1
On Wed, Jan 31, 2024 at 06:05:30PM -0500, Charles Perry wrote:
> Hello,
> 
> This patchset adds a new driver for the 7 series FPGA's SelectMAP
> interface.
> 
> The SelectMAP interface shares a common GPIO protocol with the SPI
> interface which is already in the kernel (drivers/fpga/xilinx-spi.c).
> The approach proposed in this patchset is to refactor xilinx-spi.c into
> xilinx-core.c which would handle the common GPIO protocol. This is then
> used to build two drivers, the already existing xilinx-spi.c driver and
> a newly added xilinx-selectmap.c driver.
> 
> The SelectMAP driver proposed only supports 8 bit mode. This is because
> the 16 and 32 bits mode have limitations with regards to compressed
> bitstream support as well as introducing endianness considerations.
> 
> I'm testing xilinx-selectmap.c on a custom i.MX6 board connected to an
> Artix 7 FPGA. Flashing a 913K bitstream takes 0.44 seconds.
> 
> v2: From Krzysztof Kozlowski review's:
>   * Use more conventional names for gpio DT bindings
>   * fix example in DT bindings
>   * add mc-peripheral-props.yaml to DT bindings
>   * fix various formatting mistakes
>   * Remove all occurences of the "slave" word.

Please label the series with the version number and don't send new 
versions as replies to the previous version.

Rob
  
Charles Perry Feb. 2, 2024, 8:53 p.m. UTC | #2
On Feb 2, 2024, at 3:16 PM, Rob Herring robh@kernel.org wrote:
> On Wed, Jan 31, 2024 at 06:05:30PM -0500, Charles Perry wrote:
>> Hello,
>> 
>> This patchset adds a new driver for the 7 series FPGA's SelectMAP
>> interface.
>> 
>> The SelectMAP interface shares a common GPIO protocol with the SPI
>> interface which is already in the kernel (drivers/fpga/xilinx-spi.c).
>> The approach proposed in this patchset is to refactor xilinx-spi.c into
>> xilinx-core.c which would handle the common GPIO protocol. This is then
>> used to build two drivers, the already existing xilinx-spi.c driver and
>> a newly added xilinx-selectmap.c driver.
>> 
>> The SelectMAP driver proposed only supports 8 bit mode. This is because
>> the 16 and 32 bits mode have limitations with regards to compressed
>> bitstream support as well as introducing endianness considerations.
>> 
>> I'm testing xilinx-selectmap.c on a custom i.MX6 board connected to an
>> Artix 7 FPGA. Flashing a 913K bitstream takes 0.44 seconds.
>> 
>> v2: From Krzysztof Kozlowski review's:
>>   * Use more conventional names for gpio DT bindings
>>   * fix example in DT bindings
>>   * add mc-peripheral-props.yaml to DT bindings
>>   * fix various formatting mistakes
>>   * Remove all occurences of the "slave" word.
> 
> Please label the series with the version number and don't send new
> versions as replies to the previous version.
> 
> Rob

Ok, will do.

Regards,
Charles
  

Patch

diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
index 2f689ac4ba3a3..d27a1ebf40838 100644
--- a/drivers/fpga/Kconfig
+++ b/drivers/fpga/Kconfig
@@ -64,9 +64,13 @@  config FPGA_MGR_STRATIX10_SOC
 	help
 	  FPGA manager driver support for the Intel Stratix10 SoC.
 
+config FPGA_MGR_XILINX_CORE
+	tristate
+
 config FPGA_MGR_XILINX_SPI
 	tristate "Xilinx Configuration over Slave Serial (SPI)"
 	depends on SPI
+	select FPGA_MGR_XILINX_CORE
 	help
 	  FPGA manager driver support for Xilinx FPGA configuration
 	  over slave serial interface.
diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile
index 352a2612623e0..7ec795b6a5a70 100644
--- a/drivers/fpga/Makefile
+++ b/drivers/fpga/Makefile
@@ -15,6 +15,7 @@  obj-$(CONFIG_FPGA_MGR_SOCFPGA)		+= socfpga.o
 obj-$(CONFIG_FPGA_MGR_SOCFPGA_A10)	+= socfpga-a10.o
 obj-$(CONFIG_FPGA_MGR_STRATIX10_SOC)	+= stratix10-soc.o
 obj-$(CONFIG_FPGA_MGR_TS73XX)		+= ts73xx-fpga.o
+obj-$(CONFIG_FPGA_MGR_XILINX_CORE)	+= xilinx-core.o
 obj-$(CONFIG_FPGA_MGR_XILINX_SPI)	+= xilinx-spi.o
 obj-$(CONFIG_FPGA_MGR_ZYNQ_FPGA)	+= zynq-fpga.o
 obj-$(CONFIG_FPGA_MGR_ZYNQMP_FPGA)	+= zynqmp-fpga.o
diff --git a/drivers/fpga/xilinx-core.c b/drivers/fpga/xilinx-core.c
new file mode 100644
index 0000000000000..47839b5541ddd
--- /dev/null
+++ b/drivers/fpga/xilinx-core.c
@@ -0,0 +1,210 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Common parts of the Xilinx Spartan6 and 7 Series FPGA manager drivers.
+ *
+ * Copyright (C) 2017 DENX Software Engineering
+ *
+ * Anatolij Gustschin <agust@denx.de>
+ */
+
+#include "xilinx-core.h"
+
+#include <linux/delay.h>
+#include <linux/fpga/fpga-mgr.h>
+#include <linux/gpio/consumer.h>
+#include <linux/of.h>
+
+static int get_done_gpio(struct fpga_manager *mgr)
+{
+	struct xilinx_fpga_core *core = mgr->priv;
+	int ret;
+
+	ret = gpiod_get_value(core->done);
+
+	if (ret < 0)
+		dev_err(&mgr->dev, "Error reading DONE (%d)\n", ret);
+
+	return ret;
+}
+
+static enum fpga_mgr_states xilinx_core_state(struct fpga_manager *mgr)
+{
+	if (!get_done_gpio(mgr))
+		return FPGA_MGR_STATE_RESET;
+
+	return FPGA_MGR_STATE_UNKNOWN;
+}
+
+/**
+ * wait_for_init_b - wait for the INIT_B pin to have a given state, or wait
+ * a given delay if the pin is unavailable
+ *
+ * @mgr:        The FPGA manager object
+ * @value:      Value INIT_B to wait for (1 = asserted = low)
+ * @alt_udelay: Delay to wait if the INIT_B GPIO is not available
+ *
+ * Returns 0 when the INIT_B GPIO reached the given state or -ETIMEDOUT if
+ * too much time passed waiting for that. If no INIT_B GPIO is available
+ * then always return 0.
+ */
+static int wait_for_init_b(struct fpga_manager *mgr, int value,
+			   unsigned long alt_udelay)
+{
+	struct xilinx_fpga_core *core = mgr->priv;
+	unsigned long timeout = jiffies + msecs_to_jiffies(1000);
+
+	if (core->init_b) {
+		while (time_before(jiffies, timeout)) {
+			int ret = gpiod_get_value(core->init_b);
+
+			if (ret == value)
+				return 0;
+
+			if (ret < 0) {
+				dev_err(&mgr->dev, "Error reading INIT_B (%d)\n", ret);
+				return ret;
+			}
+
+			usleep_range(100, 400);
+		}
+
+		dev_err(&mgr->dev, "Timeout waiting for INIT_B to %s\n",
+			value ? "assert" : "deassert");
+		return -ETIMEDOUT;
+	}
+
+	udelay(alt_udelay);
+
+	return 0;
+}
+
+static int xilinx_core_write_init(struct fpga_manager *mgr,
+				 struct fpga_image_info *info,
+				 const char *buf, size_t count)
+{
+	struct xilinx_fpga_core *core = mgr->priv;
+	int err;
+
+	if (info->flags & FPGA_MGR_PARTIAL_RECONFIG) {
+		dev_err(&mgr->dev, "Partial reconfiguration not supported\n");
+		return -EINVAL;
+	}
+
+	gpiod_set_value(core->prog_b, 1);
+
+	err = wait_for_init_b(mgr, 1, 1); /* min is 500 ns */
+	if (err) {
+		gpiod_set_value(core->prog_b, 0);
+		return err;
+	}
+
+	gpiod_set_value(core->prog_b, 0);
+
+	err = wait_for_init_b(mgr, 0, 0);
+	if (err)
+		return err;
+
+	if (get_done_gpio(mgr)) {
+		dev_err(&mgr->dev, "Unexpected DONE pin state...\n");
+		return -EIO;
+	}
+
+	/* program latency */
+	usleep_range(7500, 7600);
+	return 0;
+}
+
+static int xilinx_core_write(struct fpga_manager *mgr, const char *buf,
+			    size_t count)
+{
+	struct xilinx_fpga_core *core = mgr->priv;
+
+	return core->write(core, buf, count);
+}
+
+static int xilinx_core_write_complete(struct fpga_manager *mgr,
+				     struct fpga_image_info *info)
+{
+	struct xilinx_fpga_core *core = mgr->priv;
+	unsigned long timeout = jiffies + usecs_to_jiffies(info->config_complete_timeout_us);
+	bool expired = false;
+	int done;
+	int ret;
+
+	/*
+	 * This loop is carefully written such that if the driver is
+	 * scheduled out for more than 'timeout', we still check for DONE
+	 * before giving up and we apply 8 extra CCLK cycles in all cases.
+	 */
+	while (!expired) {
+		expired = time_after(jiffies, timeout);
+
+		done = get_done_gpio(mgr);
+		if (done < 0)
+			return done;
+
+		ret = core->write_one_dummy_byte(core);
+		if (ret)
+			return ret;
+
+		if (done)
+			return 0;
+	}
+
+	if (core->init_b) {
+		ret = gpiod_get_value(core->init_b);
+
+		if (ret < 0) {
+			dev_err(&mgr->dev, "Error reading INIT_B (%d)\n", ret);
+			return ret;
+		}
+
+		dev_err(&mgr->dev,
+			ret ? "CRC error or invalid device\n"
+			: "Missing sync word or incomplete bitstream\n");
+	} else {
+		dev_err(&mgr->dev, "Timeout after config data transfer\n");
+	}
+
+	return -ETIMEDOUT;
+}
+
+static const struct fpga_manager_ops xilinx_core_ops = {
+	.state = xilinx_core_state,
+	.write_init = xilinx_core_write_init,
+	.write = xilinx_core_write,
+	.write_complete = xilinx_core_write_complete,
+};
+
+int xilinx_core_probe(struct xilinx_fpga_core *core,
+					  struct device *dev,
+					  xilinx_write_func write,
+					  xilinx_write_one_dummy_byte_func write_one_dummy_byte)
+{
+	struct fpga_manager *mgr;
+
+	core->dev = dev;
+	core->write = write;
+	core->write_one_dummy_byte = write_one_dummy_byte;
+
+	/* PROGRAM_B is active low */
+	core->prog_b = devm_gpiod_get(dev, "prog_b", GPIOD_OUT_LOW);
+	if (IS_ERR(core->prog_b))
+		return dev_err_probe(dev, PTR_ERR(core->prog_b),
+				     "Failed to get PROGRAM_B gpio\n");
+
+	core->init_b = devm_gpiod_get_optional(dev, "init-b", GPIOD_IN);
+	if (IS_ERR(core->init_b))
+		return dev_err_probe(dev, PTR_ERR(core->init_b),
+				     "Failed to get INIT_B gpio\n");
+
+	core->done = devm_gpiod_get(dev, "done", GPIOD_IN);
+	if (IS_ERR(core->done))
+		return dev_err_probe(dev, PTR_ERR(core->done),
+				     "Failed to get DONE gpio\n");
+
+	mgr = devm_fpga_mgr_register(dev,
+				     "Xilinx Slave Serial FPGA Manager",
+				     &xilinx_core_ops, core);
+	return PTR_ERR_OR_ZERO(mgr);
+}
diff --git a/drivers/fpga/xilinx-core.h b/drivers/fpga/xilinx-core.h
new file mode 100644
index 0000000000000..2e6ce2235531f
--- /dev/null
+++ b/drivers/fpga/xilinx-core.h
@@ -0,0 +1,27 @@ 
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef	__XILINX_CORE_H
+#define	__XILINX_CORE_H
+
+#include <linux/device.h>
+
+struct xilinx_fpga_core;
+
+typedef int (*xilinx_write_func)(struct xilinx_fpga_core *core, const char *buf,
+			    size_t count);
+typedef int (*xilinx_write_one_dummy_byte_func)(struct xilinx_fpga_core *core);
+
+struct xilinx_fpga_core {
+	struct device *dev;
+	xilinx_write_func write;
+	xilinx_write_one_dummy_byte_func write_one_dummy_byte;
+	struct gpio_desc *prog_b;
+	struct gpio_desc *init_b;
+	struct gpio_desc *done;
+};
+
+int xilinx_core_probe(struct xilinx_fpga_core *core, struct device *dev,
+					xilinx_write_func write,
+					xilinx_write_one_dummy_byte_func write_one_dummy_byte);
+
+#endif /* __XILINX_CORE_H */
diff --git a/drivers/fpga/xilinx-spi.c b/drivers/fpga/xilinx-spi.c
index e1a227e7ff2ae..71d8d421f3c63 100644
--- a/drivers/fpga/xilinx-spi.c
+++ b/drivers/fpga/xilinx-spi.c
@@ -10,127 +10,25 @@ 
  * the slave serial configuration interface.
  */
 
-#include <linux/delay.h>
-#include <linux/device.h>
-#include <linux/fpga/fpga-mgr.h>
-#include <linux/gpio/consumer.h>
+#include "xilinx-core.h"
+
 #include <linux/module.h>
 #include <linux/mod_devicetable.h>
 #include <linux/of.h>
 #include <linux/spi/spi.h>
-#include <linux/sizes.h>
 
 struct xilinx_spi_conf {
+	struct xilinx_fpga_core core;
 	struct spi_device *spi;
-	struct gpio_desc *prog_b;
-	struct gpio_desc *init_b;
-	struct gpio_desc *done;
 };
 
-static int get_done_gpio(struct fpga_manager *mgr)
-{
-	struct xilinx_spi_conf *conf = mgr->priv;
-	int ret;
-
-	ret = gpiod_get_value(conf->done);
-
-	if (ret < 0)
-		dev_err(&mgr->dev, "Error reading DONE (%d)\n", ret);
-
-	return ret;
-}
-
-static enum fpga_mgr_states xilinx_spi_state(struct fpga_manager *mgr)
-{
-	if (!get_done_gpio(mgr))
-		return FPGA_MGR_STATE_RESET;
-
-	return FPGA_MGR_STATE_UNKNOWN;
-}
-
-/**
- * wait_for_init_b - wait for the INIT_B pin to have a given state, or wait
- * a given delay if the pin is unavailable
- *
- * @mgr:        The FPGA manager object
- * @value:      Value INIT_B to wait for (1 = asserted = low)
- * @alt_udelay: Delay to wait if the INIT_B GPIO is not available
- *
- * Returns 0 when the INIT_B GPIO reached the given state or -ETIMEDOUT if
- * too much time passed waiting for that. If no INIT_B GPIO is available
- * then always return 0.
- */
-static int wait_for_init_b(struct fpga_manager *mgr, int value,
-			   unsigned long alt_udelay)
-{
-	struct xilinx_spi_conf *conf = mgr->priv;
-	unsigned long timeout = jiffies + msecs_to_jiffies(1000);
-
-	if (conf->init_b) {
-		while (time_before(jiffies, timeout)) {
-			int ret = gpiod_get_value(conf->init_b);
-
-			if (ret == value)
-				return 0;
-
-			if (ret < 0) {
-				dev_err(&mgr->dev, "Error reading INIT_B (%d)\n", ret);
-				return ret;
-			}
-
-			usleep_range(100, 400);
-		}
-
-		dev_err(&mgr->dev, "Timeout waiting for INIT_B to %s\n",
-			value ? "assert" : "deassert");
-		return -ETIMEDOUT;
-	}
-
-	udelay(alt_udelay);
-
-	return 0;
-}
-
-static int xilinx_spi_write_init(struct fpga_manager *mgr,
-				 struct fpga_image_info *info,
-				 const char *buf, size_t count)
-{
-	struct xilinx_spi_conf *conf = mgr->priv;
-	int err;
-
-	if (info->flags & FPGA_MGR_PARTIAL_RECONFIG) {
-		dev_err(&mgr->dev, "Partial reconfiguration not supported\n");
-		return -EINVAL;
-	}
-
-	gpiod_set_value(conf->prog_b, 1);
-
-	err = wait_for_init_b(mgr, 1, 1); /* min is 500 ns */
-	if (err) {
-		gpiod_set_value(conf->prog_b, 0);
-		return err;
-	}
-
-	gpiod_set_value(conf->prog_b, 0);
-
-	err = wait_for_init_b(mgr, 0, 0);
-	if (err)
-		return err;
-
-	if (get_done_gpio(mgr)) {
-		dev_err(&mgr->dev, "Unexpected DONE pin state...\n");
-		return -EIO;
-	}
-
-	/* program latency */
-	usleep_range(7500, 7600);
-	return 0;
-}
+#define to_xilinx_spi_conf(obj) \
+	container_of(obj, struct xilinx_spi_conf, core)
 
-static int xilinx_spi_write(struct fpga_manager *mgr, const char *buf,
+static int xilinx_spi_write(struct xilinx_fpga_core *core, const char *buf,
 			    size_t count)
 {
-	struct xilinx_spi_conf *conf = mgr->priv;
+	struct xilinx_spi_conf *conf = to_xilinx_spi_conf(core);
 	const char *fw_data = buf;
 	const char *fw_data_end = fw_data + count;
 
@@ -143,7 +41,7 @@  static int xilinx_spi_write(struct fpga_manager *mgr, const char *buf,
 
 		ret = spi_write(conf->spi, fw_data, stride);
 		if (ret) {
-			dev_err(&mgr->dev, "SPI error in firmware write: %d\n",
+			dev_err(core->dev, "SPI error in firmware write: %d\n",
 				ret);
 			return ret;
 		}
@@ -153,77 +51,22 @@  static int xilinx_spi_write(struct fpga_manager *mgr, const char *buf,
 	return 0;
 }
 
-static int xilinx_spi_apply_cclk_cycles(struct xilinx_spi_conf *conf)
+static int xilinx_spi_apply_cclk_cycles(struct xilinx_fpga_core *core)
 {
-	struct spi_device *spi = conf->spi;
+	struct xilinx_spi_conf *conf = to_xilinx_spi_conf(core);
 	const u8 din_data[1] = { 0xff };
 	int ret;
 
 	ret = spi_write(conf->spi, din_data, sizeof(din_data));
 	if (ret)
-		dev_err(&spi->dev, "applying CCLK cycles failed: %d\n", ret);
+		dev_err(core->dev, "applying CCLK cycles failed: %d\n", ret);
 
 	return ret;
 }
 
-static int xilinx_spi_write_complete(struct fpga_manager *mgr,
-				     struct fpga_image_info *info)
-{
-	struct xilinx_spi_conf *conf = mgr->priv;
-	unsigned long timeout = jiffies + usecs_to_jiffies(info->config_complete_timeout_us);
-	bool expired = false;
-	int done;
-	int ret;
-
-	/*
-	 * This loop is carefully written such that if the driver is
-	 * scheduled out for more than 'timeout', we still check for DONE
-	 * before giving up and we apply 8 extra CCLK cycles in all cases.
-	 */
-	while (!expired) {
-		expired = time_after(jiffies, timeout);
-
-		done = get_done_gpio(mgr);
-		if (done < 0)
-			return done;
-
-		ret = xilinx_spi_apply_cclk_cycles(conf);
-		if (ret)
-			return ret;
-
-		if (done)
-			return 0;
-	}
-
-	if (conf->init_b) {
-		ret = gpiod_get_value(conf->init_b);
-
-		if (ret < 0) {
-			dev_err(&mgr->dev, "Error reading INIT_B (%d)\n", ret);
-			return ret;
-		}
-
-		dev_err(&mgr->dev,
-			ret ? "CRC error or invalid device\n"
-			: "Missing sync word or incomplete bitstream\n");
-	} else {
-		dev_err(&mgr->dev, "Timeout after config data transfer\n");
-	}
-
-	return -ETIMEDOUT;
-}
-
-static const struct fpga_manager_ops xilinx_spi_ops = {
-	.state = xilinx_spi_state,
-	.write_init = xilinx_spi_write_init,
-	.write = xilinx_spi_write,
-	.write_complete = xilinx_spi_write_complete,
-};
-
 static int xilinx_spi_probe(struct spi_device *spi)
 {
 	struct xilinx_spi_conf *conf;
-	struct fpga_manager *mgr;
 
 	conf = devm_kzalloc(&spi->dev, sizeof(*conf), GFP_KERNEL);
 	if (!conf)
@@ -231,26 +74,9 @@  static int xilinx_spi_probe(struct spi_device *spi)
 
 	conf->spi = spi;
 
-	/* PROGRAM_B is active low */
-	conf->prog_b = devm_gpiod_get(&spi->dev, "prog_b", GPIOD_OUT_LOW);
-	if (IS_ERR(conf->prog_b))
-		return dev_err_probe(&spi->dev, PTR_ERR(conf->prog_b),
-				     "Failed to get PROGRAM_B gpio\n");
-
-	conf->init_b = devm_gpiod_get_optional(&spi->dev, "init-b", GPIOD_IN);
-	if (IS_ERR(conf->init_b))
-		return dev_err_probe(&spi->dev, PTR_ERR(conf->init_b),
-				     "Failed to get INIT_B gpio\n");
-
-	conf->done = devm_gpiod_get(&spi->dev, "done", GPIOD_IN);
-	if (IS_ERR(conf->done))
-		return dev_err_probe(&spi->dev, PTR_ERR(conf->done),
-				     "Failed to get DONE gpio\n");
-
-	mgr = devm_fpga_mgr_register(&spi->dev,
-				     "Xilinx Slave Serial FPGA Manager",
-				     &xilinx_spi_ops, conf);
-	return PTR_ERR_OR_ZERO(mgr);
+	return xilinx_core_probe(&conf->core, &spi->dev,
+							&xilinx_spi_write,
+							&xilinx_spi_apply_cclk_cycles);
 }
 
 #ifdef CONFIG_OF