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Posted to commits@nuttx.apache.org by GitBox <gi...@apache.org> on 2020/07/03 14:19:39 UTC
[GitHub] [incubator-nuttx] dieselburner opened a new issue #1356: drivers: mtd: align spi and qspi
dieselburner opened a new issue #1356:
URL: https://github.com/apache/incubator-nuttx/issues/1356
**Issue:**
Currently there's a misalignment in MTD drivers, where some drivers are written exclusively for QSPI interfaces, while others are using standard SPI. As you know, (nearly?) all QuadSPI controller implementations allows you to use QSPI in a standard SPI way, and opposite, all QSPI devices that I have seen (I've seen things you people wouldn't believe (C)) are able to operate in a standard SPI mode.
**Example:**
1. [m25qxxx driver](https://github.com/apache/incubator-nuttx/blob/master/drivers/mtd/n25qxxx.c) is using QSPI_* functions, which means currently it is impossible to use this particular driver with standard SPI interface.
```c
static int n25qxxx_command_write(FAR struct qspi_dev_s *qspi, uint8_t cmd,
FAR const void *buffer, size_t buflen)
{
struct qspi_cmdinfo_s cmdinfo;
finfo("CMD: %02x buflen: %lu\n", cmd, (unsigned long)buflen);
cmdinfo.flags = QSPICMD_WRITEDATA;
cmdinfo.addrlen = 0;
cmdinfo.cmd = cmd;
cmdinfo.buflen = buflen;
cmdinfo.addr = 0;
cmdinfo.buffer = (FAR void *)buffer;
return QSPI_COMMAND(qspi, &cmdinfo);
}
```
2. [gd5d driver](https://github.com/apache/incubator-nuttx/blob/master/drivers/mtd/gd5f.c) is using SPI_* commands, which means currently it is impossible to use this particular driver with QSPI interface, even though this NAND chip supports QSPI.
```c
static bool gd5f_execute_write(FAR struct gd5f_dev_s *priv, uint32_t pageaddress)
{
const uint32_t row = pageaddress >> priv->pageshift;
/* Select this FLASH part */
SPI_SELECT(priv->dev, SPIDEV_FLASH(priv->spi_devid), true);
/* Send the Program Execute instruction */
SPI_SEND(priv->dev, GD5F_PROGRAM_EXECUTE);
SPI_SEND(priv->dev, (row >> 16) & 0xff);
SPI_SEND(priv->dev, (row >> 8) & 0xff);
SPI_SEND(priv->dev, row & 0xff);
/* De-select the FLASH */
SPI_SELECT(priv->dev, SPIDEV_FLASH(priv->spi_devid), false);
return gd5f_waitstatus(priv, GD5F_SR_P_FAIL, false);
}
```
**Solution:**
Ideally having some sort of a common `ops` structure that is initialized by SPI/QSPI/other_transport drivers, which then is used in MTD (and other) device drivers, by simply calling appropriate callbacks without caring what transport is being used. That's pretty much the same way how these kind of things are implemented in Linux kernel.
```c
struct spi_nor_controller_ops {
int (*prepare)(struct spi_nor *nor);
void (*unprepare)(struct spi_nor *nor);
int (*read_reg)(struct spi_nor *nor, u8 opcode, u8 *buf, size_t len);
int (*write_reg)(struct spi_nor *nor, u8 opcode, const u8 *buf,
size_t len);
ssize_t (*read)(struct spi_nor *nor, loff_t from, size_t len, u8 *buf);
ssize_t (*write)(struct spi_nor *nor, loff_t to, size_t len,
const u8 *buf);
int (*erase)(struct spi_nor *nor, loff_t offs);
};
```
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[GitHub] [incubator-nuttx] xiaoxiang781216 commented on issue #1356: drivers: mtd: align spi and qspi
Posted by GitBox <gi...@apache.org>.
xiaoxiang781216 commented on issue #1356:
URL: https://github.com/apache/incubator-nuttx/issues/1356#issuecomment-653769946
@dieselburner it's unfortunate that SPI and QSPI don't share the same common driver interface as much as possible. Most external perpherals support both SPI and QSPI at the same time, the different SPI/QSPI interface make it's very hard to write one driver for these perpherals. It will be a great contribution to make MTD/LCD work with SPI/QSPI in the consistent way.
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[GitHub] [incubator-nuttx] Ouss4 commented on issue #1356: drivers: mtd: align spi and qspi
Posted by GitBox <gi...@apache.org>.
Ouss4 commented on issue #1356:
URL: https://github.com/apache/incubator-nuttx/issues/1356#issuecomment-653633067
> That's pretty much the same way how these kind of things are implemented in Linux kernel.
This is also used in many drivers in NuttX, where usually the board logic provides the detail of the transfer to the driver through a similar `ops` structure.
There is also another way where the base driver and the different transfer protocols are implemented separately. (ex [the ssd1306 LCD](https://github.com/apache/incubator-nuttx/blob/master/drivers/lcd/ssd1306_base.c)). This second method is convenient when the protocols are somewhat independent from the board and can be implemented without too much custom logic from the board part.
Either could be used for the MTD drivers. One possible complexity is different commands for SPI and QSPI and dummy cycles required.
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[GitHub] [incubator-nuttx] Ouss4 edited a comment on issue #1356: drivers: mtd: align spi and qspi
Posted by GitBox <gi...@apache.org>.
Ouss4 edited a comment on issue #1356:
URL: https://github.com/apache/incubator-nuttx/issues/1356#issuecomment-653633067
> That's pretty much the same way how these kind of things are implemented in Linux kernel.
This is also used in many drivers in NuttX, where usually the board logic provides the detail of the transfer to the driver through a similar `ops` structure.
There is also another way where the base driver and the different transfer protocols are implemented separately. (ex [the ssd1306 LCD](https://github.com/apache/incubator-nuttx/blob/master/drivers/lcd/ssd1306_base.c)). This second method is convenient when the protocols are somewhat independent from the board and can be implemented without too much custom logic.
Either could be used for the MTD drivers. One possible complexity could be different commands for SPI and QSPI and dummy cycles required.
----------------------------------------------------------------
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[GitHub] [incubator-nuttx] Ouss4 edited a comment on issue #1356: drivers: mtd: align spi and qspi
Posted by GitBox <gi...@apache.org>.
Ouss4 edited a comment on issue #1356:
URL: https://github.com/apache/incubator-nuttx/issues/1356#issuecomment-653633067
> That's pretty much the same way how these kind of things are implemented in Linux kernel.
This is also used in many drivers in NuttX, where usually the board logic provides the detail of the transfer to the driver through a similar `ops` structure.
There is also another way where the base driver and the different transfer protocols are implemented separately. (ex [the ssd1306 LCD](https://github.com/apache/incubator-nuttx/blob/master/drivers/lcd/ssd1306_base.c)). This second method is convenient when the protocols are somewhat independent from the board and can be implemented without too much custom logic.
Either could be used for the MTD drivers. One possible complexity is different commands for SPI and QSPI and dummy cycles required.
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