On Fri, 2018-11-23 at 11:13 +0530, Jagan Teki wrote:
On Thu, Nov 22, 2018 at 2:29 PM Guochun Mao guochun.mao@mediatek.com wrote:
On Thu, 2018-11-22 at 11:51 +0530, Jagan Teki wrote:
On Wed, Nov 21, 2018 at 5:16 PM Guochun Mao guochun.mao@mediatek.com wrote:
Hi Jagan,
On Wed, 2018-11-21 at 15:08 +0530, Jagan Teki wrote:
> > +static int mtk_qspi_tx_rx(struct mtk_qspi_priv *priv) > > +{ > > + int len = 1 + priv->txlen + priv->rxlen; > > + int i, ret, idx; > > + > > + if (len > MTK_QSPI_MAX_SHIFT) > > + return -ERR_INVAL; > > + > > + writeb(len * 8, &priv->regs->cnt); > > + > > + /* start at PRGDATA5, go down to PRGDATA0 */ > > + idx = MTK_QSPI_MAX_RX_TX_SHIFT - 1; > > + > > + /* opcode */ > > + writeb(priv->op, &priv->regs->prgdata[idx]); > > + idx--; > > + > > + /* program TX data */ > > + for (i = 0; i < priv->txlen; i++, idx--) > > + writeb(priv->tx[i], &priv->regs->prgdata[idx]); > > + > > + /* clear out rest of TX registers */ > > + while (idx >= 0) { > > + writeb(0, &priv->regs->prgdata[idx]); > > + idx--; > > + } > > + > > + ret = mtk_qspi_execute_cmd(priv, MTK_QSPI_PRG_CMD); > > What does this execute do? It send command to flash, and latch data if need.
> does it intiate the controller register > based flash command or so? No, it doesn't.
> > Do you have Linux driver on the controller? Yes, it's drivers/mtd/spi-nor/mtk-quadspi.c
This sounds more specific to flash controller rather than spi driver. Can you try to write driver in mtd side itself, like Linux spi-nor. use UCLASS_SPI_FLASH
Sorry, I'm a little confused. There are many files(***qspi.c) those that used for accessing spi flash under folder drivers/spi/. However, there's no specific flash controller driver implemented under drives/mtd, only common spi_flash framework. It's different with kernel. It seems that we only need implement the spi control logic of spi-flash-controller(this part not based on flash, it only do data-xfer), and spi_flash framework will work well base on it. Isn't that the purpose of this architecture?
Understand your point, to be precise the driver may a fall in trouble after sometime, if there is an additional flash specific features will attach in future. ie reason few of flash controllers in drivers/spi were unable to move further to add their features. and ie also reason for your driver in Linux which resides in spi-nor.
You can directly write UCLASS_SPI_FLASH like sf_dataflash, I can help if any issues with probing setup etc.
Hi Jagan,
Could you reconsider this driver?
The code can match our needs for a considerable time, it's simple and doesn't disrupt current architecture.
If we switched to MTD_SPI_FLASH, there will inevitably be some duplicated codes. The current version of code adopts the sf/spi framework, it can guarantee compatibility and code reusability ratio.
If spi-mem or spi-nor was introduced to uboot in future, we can quickly implement new version code.
Thanks.
Applied to u-boot-spi/master
Thanks for your great effort for the review.
Guochun