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Date: Sat, 29 Sep 2018 17:40:23 +0200
From: Boris Brezillon <boris.brezillon@...tlin.com>
To: Yogesh Gaur <yogeshnarayan.gaur@....com>
Cc: linux-mtd@...ts.infradead.org, marek.vasut@...il.com,
linux-spi@...r.kernel.org, devicetree@...r.kernel.org,
robh@...nel.org, mark.rutland@....com, shawnguo@...nel.org,
linux-arm-kernel@...ts.infradead.org, computersforpeace@...il.com,
frieder.schrempf@...eet.de, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 1/5] spi: spi-mem: Add driver for NXP FlexSPI
controller
Hi Yogesh,
On Fri, 21 Sep 2018 15:51:59 +0530
Yogesh Gaur <yogeshnarayan.gaur@....com> wrote:
> +/* Registers used by the driver */
> +#define FSPI_MCR0 0x00
> +#define FSPI_MCR0_AHB_TIMEOUT_SHIFT 24
> +#define FSPI_MCR0_AHB_TIMEOUT_MASK (0xFF << FSPI_MCR0_AHB_TIMEOUT_SHIFT)
> +#define FSPI_MCR0_IP_TIMEOUT_SHIFT 16
> +#define FSPI_MCR0_IP_TIMEOUT_MASK (0xFF << FSPI_MCR0_IP_TIMEOUT_SHIFT)
> +#define FSPI_MCR0_LEARN_EN_SHIFT 15
> +#define FSPI_MCR0_LEARN_EN_MASK (1 << FSPI_MCR0_LEARN_EN_SHIFT)
> +#define FSPI_MCR0_SCRFRUN_EN_SHIFT 14
> +#define FSPI_MCR0_SCRFRUN_EN_MASK (1 << FSPI_MCR0_SCRFRUN_EN_SHIFT)
> +#define FSPI_MCR0_OCTCOMB_EN_SHIFT 13
> +#define FSPI_MCR0_OCTCOMB_EN_MASK (1 << FSPI_MCR0_OCTCOMB_EN_SHIFT)
> +#define FSPI_MCR0_DOZE_EN_SHIFT 12
> +#define FSPI_MCR0_DOZE_EN_MASK (1 << FSPI_MCR0_DOZE_EN_SHIFT)
> +#define FSPI_MCR0_HSEN_SHIFT 11
> +#define FSPI_MCR0_HSEN_MASK (1 << FSPI_MCR0_HSEN_SHIFT)
> +#define FSPI_MCR0_SERCLKDIV_SHIFT 8
> +#define FSPI_MCR0_SERCLKDIV_MASK (7 << FSPI_MCR0_SERCLKDIV_SHIFT)
> +#define FSPI_MCR0_ATDF_EN_SHIFT 7
> +#define FSPI_MCR0_ATDF_EN_MASK (1 << FSPI_MCR0_ATDF_EN_SHIFT)
> +#define FSPI_MCR0_ARDF_EN_SHIFT 6
> +#define FSPI_MCR0_ARDF_EN_MASK (1 << FSPI_MCR0_ARDF_EN_SHIFT)
> +#define FSPI_MCR0_RXCLKSRC_SHIFT 4
> +#define FSPI_MCR0_RXCLKSRC_MASK (3 << FSPI_MCR0_RXCLKSRC_SHIFT)
> +#define FSPI_MCR0_END_CFG_SHIFT 2
> +#define FSPI_MCR0_END_CFG_MASK (3 << FSPI_MCR0_END_CFG_SHIFT)
> +#define FSPI_MCR0_MDIS_SHIFT 1
> +#define FSPI_MCR0_MDIS_MASK (1 << FSPI_MCR0_MDIS_SHIFT)
> +#define FSPI_MCR0_SWRST_SHIFT 0
> +#define FSPI_MCR0_SWRST_MASK (1 << FSPI_MCR0_SWRST_SHIFT)
Do we really need all those _SHIFT/_MASK defs? I mean
#define FSPI_MCR0_SWRST BIT(0)
or
#define FSPI_MCR0_AHB_TIMEOUT(x) ((x) << 24)
#define FSPI_MCR0_AHB_TIMEOUT_MASK GENMASK(31, 24)
are just fine.
> +
> +enum nxp_fspi_devtype {
> + NXP_FSPI_LX2160A,
> +};
I'm pretty sure you don't need this enum if you describe all dev caps
in the nxp_fspi_devtype_data struct.
> +
> +struct nxp_fspi_devtype_data {
> + enum nxp_fspi_devtype devtype;
> + unsigned int rxfifo;
> + unsigned int txfifo;
> + unsigned int ahb_buf_size;
> + unsigned int quirks;
> + bool endianness;
How about renaming this variable big_endian and dropping the
{L,B}_ENDIAN macros?
> +};
[...]
> +struct nxp_fspi {
> + void __iomem *iobase;
> + void __iomem *ahb_addr;
> + u32 memmap_phy;
> + u32 memmap_phy_size;
> + struct clk *clk, *clk_en;
> + struct device *dev;
> + struct completion c;
> + const struct nxp_fspi_devtype_data *devtype_data;
> + struct mutex lock;
> + struct pm_qos_request pm_qos_req;
> + int selected;
> + void (*write)(u32 val, void __iomem *addr);
> + u32 (*read)(void __iomem *addr);
> +};
> +
> +static void fspi_writel_be(u32 val, void __iomem *addr)
> +{
> + iowrite32be(val, addr);
> +}
> +
> +static void fspi_writel(u32 val, void __iomem *addr)
> +{
> + iowrite32(val, addr);
> +}
> +
> +static u32 fspi_readl_be(void __iomem *addr)
> +{
> + return ioread32be(addr);
> +}
> +
> +static u32 fspi_readl(void __iomem *addr)
> +{
> + return ioread32(addr);
> +}
Hm, I'd recommend dropping the ->read/write() hooks and providing the
following functions:
static void fspi_writel(struct nxp_fspi *f, u32 val, void __iomem *addr)
{
if (f->big_endian)
iowrite32be(val, addr);
else
iowrite32(val, addr);
}
static u32 fspi_readl(struct nxp_fspi *f, void __iomem *addr)
{
if (f->big_endian)
return ioread32be(addr);
else
return ioread32(addr);
}
> +
> +static irqreturn_t nxp_fspi_irq_handler(int irq, void *dev_id)
> +{
> + struct nxp_fspi *f = dev_id;
> + u32 reg;
> +
> + /* clear interrupt */
> + reg = f->read(f->iobase + FSPI_INTR);
> + f->write(FSPI_INTR_IPCMDDONE_MASK, f->iobase + FSPI_INTR);
> +
> + if (reg & FSPI_INTR_IPCMDDONE_MASK)
> + complete(&f->c);
> +
> + return IRQ_HANDLED;
> +}
[...]
> +/*
> + * If the slave device content being changed by Write/Erase, need to
> + * invalidate the AHB buffer. This can be achieved by doing the reset
> + * of controller after setting MCR0[SWRESET] bit.
> + */
> +static inline void nxp_fspi_invalid(struct nxp_fspi *f)
> +{
> + u32 reg;
> +
> + reg = f->read(f->iobase + FSPI_MCR0);
> + f->write(reg | FSPI_MCR0_SWRST_MASK, f->iobase + FSPI_MCR0);
> +
> + while (f->read(f->iobase + FSPI_MCR0) & FSPI_MCR0_SWRST_MASK)
> + ;
Did you consider using readl_poll_timeout[_atomic]()?
if (f->big_endian)
mask = (u32)cpu_to_be32(FSPI_MCR0_SWRST_MASK);
else
mask = (u32)cpu_to_be32(FSPI_MCR0_SWRST_MASK);
ret = readl_poll_timeout(f->iobase + FSPI_MCR0, reg,
reg & mask, 0, FSPI_SWRST_TIMEOUT);
WARN_ON(ret);
> +}
[...]
> +static void nxp_fspi_read_ahb(struct nxp_fspi *f, const struct spi_mem_op *op)
> +{
> + u32 len = op->data.nbytes;
> +
> + /* Read out the data directly from the AHB buffer. */
> + memcpy_fromio(op->data.buf.in, (f->ahb_addr + op->addr.val), len);
Don't know if it's supported, but if it is, I recommend using DMA to do
this copy, because otherwise you might stall the CPU for quite a long
time if the flash is operating in a low-speed mode, and RT maintainers
will complain about that at some point ;-).
> +}
> +
> +static void nxp_fspi_fill_txfifo(struct nxp_fspi *f,
> + const struct spi_mem_op *op)
> +{
> + void __iomem *base = f->iobase;
> + int i, j;
> + int size, tmp_size, wm_size;
> + u32 data = 0;
> + u32 *txbuf = (u32 *) op->data.buf.out;
> +
> + /* clear the TX FIFO. */
> + f->write(FSPI_IPTXFCR_CLR_MASK, base + FSPI_IPTXFCR);
> +
> + /* Default value of water mark level is 8 bytes. */
> + wm_size = 8;
> + size = op->data.nbytes / wm_size;
> + for (i = 0; i < size; i++) {
> + /* Wait for TXFIFO empty */
> + while (!(f->read(base + FSPI_INTR) & FSPI_INTR_IPTXWE_MASK))
> + ;
Use readl_poll_timeout(), or even better, provide an helper
(fspi_readl_poll_timeout()?) that hides the BE/LE stuff, so that you
can reuse it when this pattern occurs.
[...]
> +static int nxp_fspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
> +{
> + struct nxp_fspi *f = spi_controller_get_devdata(mem->spi->master);
> + void __iomem *base = f->iobase;
> + int err = 0;
> + unsigned int timeout = 1000;
> +
> + mutex_lock(&f->lock);
> +
> + /* wait for the controller being ready */
> + do {
> + u32 status;
> +
> + status = f->read(base + FSPI_STS0);
> + if ((status & FSPI_STS0_ARB_IDLE_MASK) &&
> + (status & FSPI_STS0_SEQ_IDLE_MASK))
> + break;
> + udelay(1);
> + dev_dbg(f->dev, "The controller is busy, 0x%x\n", status);
Same here.
Note that I didn't spend time looking at how the IP works, which
explains why I focus on tiny details here. Unfortunately, I won't have
time to review the driver in more details, so I'll leave that to
someone else, or let Mark decides if he's happy enough with the current
version.
Regards,
Boris
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