Hi all,
this series adds support for the Lattice MachXO2 FPGA chip, programmed
over Slave SPI.
Tested on a raspberry pi3, beaglebone black (little endian mode) and imx6
hummingboard (big endian mode) + bugblat's pif2 fpga hat (machxo2 7000HC) or
tinyfpga A1/A2 (machxo2 256HC / 1200HC), in SPI slave mode with varying bus
speed.
Changes since v6:
* added the SPDX boilerplate
* switched to pr_debug() and renamed MACHXO2_DEBUG to DEBUG
Paolo Pisati (2):
dt: bindings: fpga: add lattice machxo2 slave spi binding description
fpga: lattice machxo2: Add Lattice MachXO2 support
.../bindings/fpga/lattice-machxo2-spi.txt | 29 ++
drivers/fpga/Kconfig | 8 +
drivers/fpga/Makefile | 1 +
drivers/fpga/machxo2-spi.c | 405 +++++++++++++++++++++
4 files changed, 443 insertions(+)
create mode 100644 Documentation/devicetree/bindings/fpga/lattice-machxo2-spi.txt
create mode 100644 drivers/fpga/machxo2-spi.c
--
2.7.4
This patch adds support to the FPGA manager for programming
MachXO2 device’s internal flash memory, via slave SPI.
Signed-off-by: Paolo Pisati <[email protected]>
---
drivers/fpga/Kconfig | 8 +
drivers/fpga/Makefile | 1 +
drivers/fpga/machxo2-spi.c | 405 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 414 insertions(+)
create mode 100644 drivers/fpga/machxo2-spi.c
diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
index ad5448f..65ccbc5 100644
--- a/drivers/fpga/Kconfig
+++ b/drivers/fpga/Kconfig
@@ -38,6 +38,14 @@ config FPGA_MGR_ALTERA_PS_SPI
FPGA manager driver support for Altera Arria/Cyclone/Stratix
using the passive serial interface over SPI.
+config FPGA_MGR_MACHXO2_SPI
+ tristate "Lattice MachXO2 SPI"
+ depends on SPI
+ help
+ FPGA manager driver support for Lattice MachXO2 configuration
+ over slave SPI interface.
+
+
config FPGA_MGR_SOCFPGA
tristate "Altera SOCFPGA FPGA Manager"
depends on ARCH_SOCFPGA || COMPILE_TEST
diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile
index f98dcf1..38abb08 100644
--- a/drivers/fpga/Makefile
+++ b/drivers/fpga/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_FPGA) += fpga-mgr.o
obj-$(CONFIG_FPGA_MGR_ALTERA_CVP) += altera-cvp.o
obj-$(CONFIG_FPGA_MGR_ALTERA_PS_SPI) += altera-ps-spi.o
obj-$(CONFIG_FPGA_MGR_ICE40_SPI) += ice40-spi.o
+obj-$(CONFIG_FPGA_MGR_MACHXO2_SPI) += machxo2-spi.o
obj-$(CONFIG_FPGA_MGR_SOCFPGA) += socfpga.o
obj-$(CONFIG_FPGA_MGR_SOCFPGA_A10) += socfpga-a10.o
obj-$(CONFIG_FPGA_MGR_TS73XX) += ts73xx-fpga.o
diff --git a/drivers/fpga/machxo2-spi.c b/drivers/fpga/machxo2-spi.c
new file mode 100644
index 0000000..9508608
--- /dev/null
+++ b/drivers/fpga/machxo2-spi.c
@@ -0,0 +1,405 @@
+// SPDX-License-Identifier: GPL-2.0
+// Lattice MachXO2 Slave SPI Driver
+//
+// Manage Lattice FPGA firmware that is loaded over SPI using
+// the slave serial configuration interface.
+//
+// Copyright (C) 2018 Paolo Pisati <[email protected]>
+
+//#define DEBUG
+
+#include <linux/delay.h>
+#include <linux/fpga/fpga-mgr.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/spi/spi.h>
+
+/* MachXO2 Programming Guide - sysCONFIG Programming Commands */
+#define IDCODE_PUB {0xe0, 0x00, 0x00, 0x00}
+#define ISC_ENABLE {0xc6, 0x08, 0x00, 0x00}
+#define ISC_ERASE {0x0e, 0x04, 0x00, 0x00}
+#define ISC_PROGRAMDONE {0x5e, 0x00, 0x00, 0x00}
+#define LSC_INITADDRESS {0x46, 0x00, 0x00, 0x00}
+#define LSC_PROGINCRNV {0x70, 0x00, 0x00, 0x01}
+#define LSC_READ_STATUS {0x3c, 0x00, 0x00, 0x00}
+#define LSC_REFRESH {0x79, 0x00, 0x00, 0x00}
+
+/*
+ * Max CCLK in Slave SPI mode according to 'MachXO2 Family Data
+ * Sheet' sysCONFIG Port Timing Specifications (3-36)
+ */
+#define MACHXO2_MAX_SPEED 66000000
+
+#define MACHXO2_LOW_DELAY 5 /* us */
+#define MACHXO2_HIGH_DELAY 200 /* us */
+#define MACHXO2_REFRESH 4800 /* us */
+#define MACHXO2_MAX_BUSY_LOOP 128
+#define MACHXO2_MAX_REFRESH_LOOP 16
+
+#define MACHXO2_PAGE_SIZE 16
+#define MACHXO2_BUF_SIZE (MACHXO2_PAGE_SIZE + 4)
+
+/* Status register bits, errors and error mask */
+#define BUSY 12
+#define DONE 8
+#define DVER 27
+#define ENAB 9
+#define ERRBITS 23
+#define ERRMASK 7
+#define FAIL 13
+
+#define ENOERR 0 /* no error */
+#define EID 1
+#define ECMD 2
+#define ECRC 3
+#define EPREAM 4 /* preamble error */
+#define EABRT 5 /* abort error */
+#define EOVERFL 6 /* overflow error */
+#define ESDMEOF 7 /* SDM EOF */
+
+static inline u8 get_err(unsigned long *status)
+{
+ return (*status >> ERRBITS) & ERRMASK;
+}
+
+static int get_status(struct spi_device *spi, unsigned long *status)
+{
+ struct spi_message msg;
+ struct spi_transfer rx, tx;
+ u8 cmd[] = LSC_READ_STATUS;
+ int ret;
+
+ memset(&rx, 0, sizeof(rx));
+ memset(&tx, 0, sizeof(tx));
+ tx.tx_buf = cmd;
+ tx.len = sizeof(cmd);
+ rx.rx_buf = status;
+ rx.len = 4;
+ spi_message_init(&msg);
+ spi_message_add_tail(&tx, &msg);
+ spi_message_add_tail(&rx, &msg);
+ ret = spi_sync(spi, &msg);
+ if (ret)
+ return ret;
+
+ *status = be32_to_cpu(*status);
+ return 0;
+}
+
+#ifdef DEBUG
+static void dump_status_reg(unsigned long *status)
+{
+ char *ferr;
+
+ switch (get_err(status)) {
+ case ENOERR:
+ ferr = "No Error";
+ break;
+ case EID:
+ ferr = "ID ERR";
+ break;
+ case ECMD:
+ ferr = "CMD ERR";
+ break;
+ case ECRC:
+ ferr = "CRC ERR";
+ break;
+ case EPREAM:
+ ferr = "Preamble ERR";
+ break;
+ case EABRT:
+ ferr = "Abort ERR";
+ break;
+ case EOVERFL:
+ ferr = "Overflow ERR";
+ break;
+ case ESDMEOF:
+ ferr = "SDM EOF";
+ break;
+ default:
+ ferr = "Default switch case";
+ }
+ pr_debug("machxo2 status: 0x%08lX - done=%d, cfgena=%d, busy=%d, fail=%d, devver=%d, err=%s\n",
+ *status, test_bit(DONE, status), test_bit(ENAB, status),
+ test_bit(BUSY, status), test_bit(FAIL, status),
+ test_bit(DVER, status), ferr);
+}
+#else
+static void dump_status_reg(unsigned long *status) {}
+#endif
+
+static int wait_until_not_busy(struct spi_device *spi)
+{
+ unsigned long status;
+ int ret, loop = 0;
+
+ do {
+ ret = get_status(spi, &status);
+ if (ret)
+ break;
+ if (++loop >= MACHXO2_MAX_BUSY_LOOP) {
+ ret = -EBUSY;
+ break;
+ }
+ } while (test_bit(BUSY, &status));
+
+ return ret;
+}
+
+static int machxo2_cleanup(struct fpga_manager *mgr)
+{
+ struct spi_device *spi = mgr->priv;
+ struct spi_message msg;
+ struct spi_transfer tx[2];
+ u8 erase[] = ISC_ERASE;
+ u8 refresh[] = LSC_REFRESH;
+ int ret;
+
+ memset(tx, 0, sizeof(tx));
+ spi_message_init(&msg);
+ tx[0].tx_buf = &erase;
+ tx[0].len = sizeof(erase);
+ spi_message_add_tail(&tx[0], &msg);
+ ret = spi_sync(spi, &msg);
+ if (ret)
+ goto fail;
+
+ ret = wait_until_not_busy(spi);
+ if (ret)
+ goto fail;
+
+ spi_message_init(&msg);
+ tx[1].tx_buf = &refresh;
+ tx[1].len = sizeof(refresh);
+ tx[1].delay_usecs = MACHXO2_REFRESH;
+ spi_message_add_tail(&tx[1], &msg);
+ ret = spi_sync(spi, &msg);
+ if (ret)
+ goto fail;
+
+ return 0;
+fail:
+ dev_err(&mgr->dev, "Cleanup failed\n");
+ return ret;
+}
+
+static enum fpga_mgr_states machxo2_spi_state(struct fpga_manager *mgr)
+{
+ return FPGA_MGR_STATE_UNKNOWN;
+}
+
+static int machxo2_write_init(struct fpga_manager *mgr,
+ struct fpga_image_info *info,
+ const char *buf, size_t count)
+{
+ struct spi_device *spi = mgr->priv;
+ struct spi_message msg;
+ struct spi_transfer tx[3];
+ u8 enable[] = ISC_ENABLE;
+ u8 erase[] = ISC_ERASE;
+ u8 initaddr[] = LSC_INITADDRESS;
+ unsigned long status;
+ int ret;
+
+ if ((info->flags & FPGA_MGR_PARTIAL_RECONFIG)) {
+ dev_err(&mgr->dev,
+ "Partial reconfiguration is not supported\n");
+ return -ENOTSUPP;
+ }
+
+ get_status(spi, &status);
+ dump_status_reg(&status);
+ memset(tx, 0, sizeof(tx));
+ spi_message_init(&msg);
+ tx[0].tx_buf = &enable;
+ tx[0].len = sizeof(enable);
+ tx[0].delay_usecs = MACHXO2_LOW_DELAY;
+ spi_message_add_tail(&tx[0], &msg);
+
+ tx[1].tx_buf = &erase;
+ tx[1].len = sizeof(erase);
+ spi_message_add_tail(&tx[1], &msg);
+ ret = spi_sync(spi, &msg);
+ if (ret)
+ goto fail;
+
+ ret = wait_until_not_busy(spi);
+ if (ret)
+ goto fail;
+
+ get_status(spi, &status);
+ if (test_bit(FAIL, &status))
+ goto fail;
+ dump_status_reg(&status);
+
+ spi_message_init(&msg);
+ tx[2].tx_buf = &initaddr;
+ tx[2].len = sizeof(initaddr);
+ spi_message_add_tail(&tx[2], &msg);
+ ret = spi_sync(spi, &msg);
+ if (ret)
+ goto fail;
+
+ get_status(spi, &status);
+ dump_status_reg(&status);
+ return 0;
+fail:
+ dev_err(&mgr->dev, "Error during FPGA init.\n");
+ return ret;
+}
+
+static int machxo2_write(struct fpga_manager *mgr, const char *buf,
+ size_t count)
+{
+ struct spi_device *spi = mgr->priv;
+ struct spi_message msg;
+ struct spi_transfer tx;
+ u8 progincr[] = LSC_PROGINCRNV;
+ u8 payload[MACHXO2_BUF_SIZE];
+ unsigned long status;
+ int i, ret;
+
+ if (count % MACHXO2_PAGE_SIZE != 0) {
+ dev_err(&mgr->dev, "Malformed payload.\n");
+ return -EINVAL;
+ }
+ get_status(spi, &status);
+ dump_status_reg(&status);
+ memcpy(payload, &progincr, sizeof(progincr));
+ for (i = 0; i < count; i += MACHXO2_PAGE_SIZE) {
+ memcpy(&payload[sizeof(progincr)], &buf[i], MACHXO2_PAGE_SIZE);
+ memset(&tx, 0, sizeof(tx));
+ spi_message_init(&msg);
+ tx.tx_buf = payload;
+ tx.len = MACHXO2_BUF_SIZE;
+ tx.delay_usecs = MACHXO2_HIGH_DELAY;
+ spi_message_add_tail(&tx, &msg);
+ ret = spi_sync(spi, &msg);
+ if (ret) {
+ dev_err(&mgr->dev, "Error loading the bitstream.\n");
+ return ret;
+ }
+ }
+ get_status(spi, &status);
+ dump_status_reg(&status);
+
+ return 0;
+}
+
+static int machxo2_write_complete(struct fpga_manager *mgr,
+ struct fpga_image_info *info)
+{
+ struct spi_device *spi = mgr->priv;
+ struct spi_message msg;
+ struct spi_transfer tx[2];
+ u8 progdone[] = ISC_PROGRAMDONE;
+ u8 refresh[] = LSC_REFRESH;
+ unsigned long status;
+ int ret, refreshloop = 0;
+
+ memset(tx, 0, sizeof(tx));
+ spi_message_init(&msg);
+ tx[0].tx_buf = &progdone;
+ tx[0].len = sizeof(progdone);
+ spi_message_add_tail(&tx[0], &msg);
+ ret = spi_sync(spi, &msg);
+ if (ret)
+ goto fail;
+ ret = wait_until_not_busy(spi);
+ if (ret)
+ goto fail;
+
+ get_status(spi, &status);
+ dump_status_reg(&status);
+ if (!test_bit(DONE, &status)) {
+ machxo2_cleanup(mgr);
+ goto fail;
+ }
+
+ do {
+ spi_message_init(&msg);
+ tx[1].tx_buf = &refresh;
+ tx[1].len = sizeof(refresh);
+ tx[1].delay_usecs = MACHXO2_REFRESH;
+ spi_message_add_tail(&tx[1], &msg);
+ ret = spi_sync(spi, &msg);
+ if (ret)
+ goto fail;
+
+ /* check refresh status */
+ get_status(spi, &status);
+ dump_status_reg(&status);
+ if (!test_bit(BUSY, &status) && test_bit(DONE, &status) &&
+ get_err(&status) == ENOERR)
+ break;
+ if (++refreshloop == MACHXO2_MAX_REFRESH_LOOP) {
+ machxo2_cleanup(mgr);
+ goto fail;
+ }
+ } while (1);
+
+ get_status(spi, &status);
+ dump_status_reg(&status);
+ return 0;
+fail:
+ dev_err(&mgr->dev, "Refresh failed.\n");
+ return ret;
+}
+
+static const struct fpga_manager_ops machxo2_ops = {
+ .state = machxo2_spi_state,
+ .write_init = machxo2_write_init,
+ .write = machxo2_write,
+ .write_complete = machxo2_write_complete,
+};
+
+static int machxo2_spi_probe(struct spi_device *spi)
+{
+ struct device *dev = &spi->dev;
+
+ if (spi->max_speed_hz > MACHXO2_MAX_SPEED) {
+ dev_err(dev, "Speed is too high\n");
+ return -EINVAL;
+ }
+
+ return fpga_mgr_register(dev, "Lattice MachXO2 SPI FPGA Manager",
+ &machxo2_ops, spi);
+}
+
+static int machxo2_spi_remove(struct spi_device *spi)
+{
+ struct device *dev = &spi->dev;
+
+ fpga_mgr_unregister(dev);
+
+ return 0;
+}
+
+static const struct of_device_id of_match[] = {
+ { .compatible = "lattice,machxo2-slave-spi", },
+ {}
+};
+MODULE_DEVICE_TABLE(of, of_match);
+
+static const struct spi_device_id lattice_ids[] = {
+ { "machxo2-slave-spi", 0 },
+ { },
+};
+MODULE_DEVICE_TABLE(spi, lattice_ids);
+
+static struct spi_driver machxo2_spi_driver = {
+ .driver = {
+ .name = "machxo2-slave-spi",
+ .of_match_table = of_match_ptr(of_match),
+ },
+ .probe = machxo2_spi_probe,
+ .remove = machxo2_spi_remove,
+ .id_table = lattice_ids,
+};
+
+module_spi_driver(machxo2_spi_driver)
+
+MODULE_AUTHOR("Paolo Pisati <[email protected]>");
+MODULE_DESCRIPTION("Load Lattice FPGA firmware over SPI");
+MODULE_LICENSE("GPL v2");
--
2.7.4
Add dt binding documentation details for Lattice MachXO2 FPGA configuration
over Slave SPI interface.
Signed-off-by: Paolo Pisati <[email protected]>
Acked-by: Rob Herring <[email protected]>
Acked-by: Moritz Fischer <[email protected]>
Acked-by: Alan Tull <[email protected]>
---
.../bindings/fpga/lattice-machxo2-spi.txt | 29 ++++++++++++++++++++++
1 file changed, 29 insertions(+)
create mode 100644 Documentation/devicetree/bindings/fpga/lattice-machxo2-spi.txt
diff --git a/Documentation/devicetree/bindings/fpga/lattice-machxo2-spi.txt b/Documentation/devicetree/bindings/fpga/lattice-machxo2-spi.txt
new file mode 100644
index 0000000..a8c362e
--- /dev/null
+++ b/Documentation/devicetree/bindings/fpga/lattice-machxo2-spi.txt
@@ -0,0 +1,29 @@
+Lattice MachXO2 Slave SPI FPGA Manager
+
+Lattice MachXO2 FPGAs support a method of loading the bitstream over
+a 'slave SPI' interface.
+
+See 'MachXO2ProgrammingandConfigurationUsageGuide.pdf' on http://www.latticesemi.com
+
+Required properties:
+- compatible: should contain "lattice,machxo2-slave-spi"
+- reg: spi chip select of the FPGA
+
+Example for full FPGA configuration:
+
+ fpga-region0 {
+ compatible = "fpga-region";
+ fpga-mgr = <&fpga_mgr_spi>;
+ #address-cells = <0x1>;
+ #size-cells = <0x1>;
+ };
+
+ spi1: spi@2000 {
+ ...
+
+ fpga_mgr_spi: fpga-mgr@0 {
+ compatible = "lattice,machxo2-slave-spi";
+ spi-max-frequency = <8000000>;
+ reg = <0>;
+ };
+ };
--
2.7.4
On Wed, 2018-03-21 at 18:35 +0100, Paolo Pisati wrote:
> This patch adds support to the FPGA manager for programming
> MachXO2 device’s internal flash memory, via slave SPI.
style trivia:
> diff --git a/drivers/fpga/machxo2-spi.c b/drivers/fpga/machxo2-spi.c
[]
> +static int get_status(struct spi_device *spi, unsigned long *status)
> +{
> + struct spi_message msg;
> + struct spi_transfer rx, tx;
> + u8 cmd[] = LSC_READ_STATUS;
static const u8 cmd[]
here and everywhere else as all the tx_buf assignments
of cmd are to const void *
> + int ret;
> +
> + memset(&rx, 0, sizeof(rx));
> + memset(&tx, 0, sizeof(tx));
> + tx.tx_buf = cmd;
[]
> +#ifdef DEBUG
> +static void dump_status_reg(unsigned long *status)
> +{
Instead of multiple declarations of dump_status_reg
it's frequently nicer to use a style like
static void debug_func(args...)
{
#ifdef DEBUG
[code...]
#endif
}
so if function arguments ever need to be changed
it's only required to be changed in one spot and
not multiply compilation tested with and without
the DEBUG definition
> + char *ferr;
> +
> + switch (get_err(status)) {
> + case ENOERR:
> + ferr = "No Error";
> + break;
> + case EID:
> + ferr = "ID ERR";
> + break;
> + case ECMD:
> + ferr = "CMD ERR";
> + break;
> + case ECRC:
> + ferr = "CRC ERR";
> + break;
> + case EPREAM:
> + ferr = "Preamble ERR";
> + break;
> + case EABRT:
> + ferr = "Abort ERR";
> + break;
> + case EOVERFL:
> + ferr = "Overflow ERR";
> + break;
> + case ESDMEOF:
> + ferr = "SDM EOF";
> + break;
> + default:
> + ferr = "Default switch case";
> + }
It's frequently nicer to use a static function
for these enum -> string conversions like:
static const char *get_err_string(unsigned long err)
{
switch (err) {
case ENOERR: return "No Error";
case EID: return "ID ERR";
case ECMD: return "CMD ERR";
[...]
}
return "default switch case";
}
> + pr_debug("machxo2 status: 0x%08lX - done=%d, cfgena=%d, busy=%d, fail=%d, devver=%d, err=%s\n",
> + *status, test_bit(DONE, status), test_bit(ENAB, status),
> + test_bit(BUSY, status), test_bit(FAIL, status),
> + test_bit(DVER, status), ferr);
So instead of ferr, this could use
get_err_string(*status)
And please try to keep a consistent alignment for
indentation of multiple line statements
> +}
> +#else
> +static void dump_status_reg(unsigned long *status) {}
> +#endif
> +
> +static int wait_until_not_busy(struct spi_device *spi)
> +{
> + unsigned long status;
> + int ret, loop = 0;
> +
> + do {
> + ret = get_status(spi, &status);
> + if (ret)
> + break;
> + if (++loop >= MACHXO2_MAX_BUSY_LOOP) {
> + ret = -EBUSY;
> + break;
> + }
> + } while (test_bit(BUSY, &status));
> +
> + return ret;
> +}
Direct returns are OK and would shorten the function
line count.
On Wed, Mar 21, 2018 at 11:04:52AM -0700, Joe Perches wrote:
>
> static const u8 cmd[]
> here and everywhere else as all the tx_buf assignments
> of cmd are to const void *
Ok
> Instead of multiple declarations of dump_status_reg
> it's frequently nicer to use a style like
>
> static void debug_func(args...)
> {
> #ifdef DEBUG
> [code...]
> #endif
> }
>
> so if function arguments ever need to be changed
> it's only required to be changed in one spot and
> not multiply compilation tested with and without
> the DEBUG definition
Ok
> It's frequently nicer to use a static function
> for these enum -> string conversions like:
>
> static const char *get_err_string(unsigned long err)
> {
> switch (err) {
> case ENOERR: return "No Error";
> case EID: return "ID ERR";
> case ECMD: return "CMD ERR";
> [...]
> }
> return "default switch case";
> }
Ok - checkpatch complained when i put the "case ...: return ...;" on the same
line as you did here, that is why i ended up with the ugly "case...: $string;
break" all on different lines
> > + pr_debug("machxo2 status: 0x%08lX - done=%d, cfgena=%d, busy=%d, fail=%d, devver=%d, err=%s\n",
> > + *status, test_bit(DONE, status), test_bit(ENAB, status),
> > + test_bit(BUSY, status), test_bit(FAIL, status),
> > + test_bit(DVER, status), ferr);
>
> So instead of ferr, this could use
> get_err_string(*status)
>
> And please try to keep a consistent alignment for
> indentation of multiple line statements
I tried, but then checkpatch complained again about the indentation of the above block
and i literally had to guess...
Anyhow, thanks, i'll send a v8 with all these style fixes.
--
bye,
p.
On Thu, 2018-03-22 at 18:26 +0100, Paolo Pisati wrote:
> > It's frequently nicer to use a static function
> > for these enum -> string conversions like:
> >
> > static const char *get_err_string(unsigned long err)
> > {
> > switch (err) {
> > case ENOERR: return "No Error";
> > case EID: return "ID ERR";
> > case ECMD: return "CMD ERR";
> > [...]
> > }
> > return "default switch case";
> > }
>
> Ok - checkpatch complained when i put the "case ...: return ...;" on the same
> line as you did here, that is why i ended up with the ugly "case...: $string;
> break" all on different lines
checkpatch is brainless and stupid and if it
recommends stupid consistency over readability,
ignore it.
> > > + pr_debug("machxo2 status: 0x%08lX - done=%d, cfgena=%d, busy=%d, fail=%d, devver=%d, err=%s\n",
> > > + *status, test_bit(DONE, status), test_bit(ENAB, status),
> > > + test_bit(BUSY, status), test_bit(FAIL, status),
> > > + test_bit(DVER, status), ferr);
> >
> > So instead of ferr, this could use
> > get_err_string(*status)
> >
> > And please try to keep a consistent alignment for
> > indentation of multiple line statements
>
> I tried, but then checkpatch complained again about the indentation of the above block
> and i literally had to guess...
I think it only complained about the
2nd line that starts *status because it
doesn't align with the open parenthesis
of pr_debug
On Wed, Mar 21, 2018 at 1:04 PM, Joe Perches <[email protected]> wrote:
> On Wed, 2018-03-21 at 18:35 +0100, Paolo Pisati wrote:
>> This patch adds support to the FPGA manager for programming
>> MachXO2 device’s internal flash memory, via slave SPI.
>
> style trivia:
>
>> diff --git a/drivers/fpga/machxo2-spi.c b/drivers/fpga/machxo2-spi.c
> []
>> +static int get_status(struct spi_device *spi, unsigned long *status)
>> +{
>> + struct spi_message msg;
>> + struct spi_transfer rx, tx;
>> + u8 cmd[] = LSC_READ_STATUS;
>
> static const u8 cmd[]
> here and everywhere else as all the tx_buf assignments
> of cmd are to const void *
Why *static* const u8 cmd[]?
Alan
>
>> + int ret;
>> +
>> + memset(&rx, 0, sizeof(rx));
>> + memset(&tx, 0, sizeof(tx));
>> + tx.tx_buf = cmd;
>
> []
>
>> +#ifdef DEBUG
>> +static void dump_status_reg(unsigned long *status)
>> +{
>
> Instead of multiple declarations of dump_status_reg
> it's frequently nicer to use a style like
>
> static void debug_func(args...)
> {
> #ifdef DEBUG
> [code...]
> #endif
> }
>
> so if function arguments ever need to be changed
> it's only required to be changed in one spot and
> not multiply compilation tested with and without
> the DEBUG definition
>
>> + char *ferr;
>> +
>> + switch (get_err(status)) {
>> + case ENOERR:
>> + ferr = "No Error";
>> + break;
>> + case EID:
>> + ferr = "ID ERR";
>> + break;
>> + case ECMD:
>> + ferr = "CMD ERR";
>> + break;
>> + case ECRC:
>> + ferr = "CRC ERR";
>> + break;
>> + case EPREAM:
>> + ferr = "Preamble ERR";
>> + break;
>> + case EABRT:
>> + ferr = "Abort ERR";
>> + break;
>> + case EOVERFL:
>> + ferr = "Overflow ERR";
>> + break;
>> + case ESDMEOF:
>> + ferr = "SDM EOF";
>> + break;
>> + default:
>> + ferr = "Default switch case";
>> + }
>
> It's frequently nicer to use a static function
> for these enum -> string conversions like:
>
> static const char *get_err_string(unsigned long err)
> {
> switch (err) {
> case ENOERR: return "No Error";
> case EID: return "ID ERR";
> case ECMD: return "CMD ERR";
> [...]
> }
> return "default switch case";
> }
>
>> + pr_debug("machxo2 status: 0x%08lX - done=%d, cfgena=%d, busy=%d, fail=%d, devver=%d, err=%s\n",
>> + *status, test_bit(DONE, status), test_bit(ENAB, status),
>> + test_bit(BUSY, status), test_bit(FAIL, status),
>> + test_bit(DVER, status), ferr);
>
> So instead of ferr, this could use
> get_err_string(*status)
>
> And please try to keep a consistent alignment for
> indentation of multiple line statements
>
>> +}
>> +#else
>> +static void dump_status_reg(unsigned long *status) {}
>> +#endif
>> +
>> +static int wait_until_not_busy(struct spi_device *spi)
>> +{
>> + unsigned long status;
>> + int ret, loop = 0;
>> +
>> + do {
>> + ret = get_status(spi, &status);
>> + if (ret)
>> + break;
>> + if (++loop >= MACHXO2_MAX_BUSY_LOOP) {
>> + ret = -EBUSY;
>> + break;
>> + }
>> + } while (test_bit(BUSY, &status));
>> +
>> + return ret;
>> +}
>
> Direct returns are OK and would shorten the function
> line count.
>
On Thu, 2018-03-22 at 16:32 -0500, Alan Tull wrote:
> On Wed, Mar 21, 2018 at 1:04 PM, Joe Perches <[email protected]> wrote:
> > On Wed, 2018-03-21 at 18:35 +0100, Paolo Pisati wrote:
> > > This patch adds support to the FPGA manager for programming
> > > MachXO2 device’s internal flash memory, via slave SPI.
> >
> > style trivia:
> >
> > > diff --git a/drivers/fpga/machxo2-spi.c b/drivers/fpga/machxo2-spi.c
> >
> > []
> > > +static int get_status(struct spi_device *spi, unsigned long *status)
> > > +{
> > > + struct spi_message msg;
> > > + struct spi_transfer rx, tx;
> > > + u8 cmd[] = LSC_READ_STATUS;
> >
> > static const u8 cmd[]
> > here and everywhere else as all the tx_buf assignments
> > of cmd are to const void *
>
> Why *static* const u8 cmd[]?
So various compilers don't reload it on each call.