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Date: Tue, 22 Feb 2022 11:49:16 +0100
From: AngeloGioacchino Del Regno
<angelogioacchino.delregno@...labora.com>
To: Leilk Liu <leilk.liu@...iatek.com>, Mark Brown <broonie@...nel.org>
Cc: Rob Herring <robh+dt@...nel.org>,
Matthias Brugger <matthias.bgg@...il.com>,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, linux-spi@...r.kernel.org,
linux-mediatek@...ts.infradead.org
Subject: Re: [PATCH V2 4/6] spi: mediatek: add spi memory support
Il 21/02/22 05:07, Leilk Liu ha scritto:
> this patch add the support of spi-mem.
>
> Signed-off-by: Leilk Liu <leilk.liu@...iatek.com>
> ---
> drivers/spi/spi-mt65xx.c | 310 ++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 309 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/spi/spi-mt65xx.c b/drivers/spi/spi-mt65xx.c
> index 5fa677a589a4..852fc008329a 100644
> --- a/drivers/spi/spi-mt65xx.c
> +++ b/drivers/spi/spi-mt65xx.c
> @@ -17,6 +17,7 @@
> #include <linux/platform_data/spi-mt65xx.h>
> #include <linux/pm_runtime.h>
> #include <linux/spi/spi.h>
> +#include <linux/spi/spi-mem.h>
> #include <linux/dma-mapping.h>
>
> #define SPI_CFG0_REG 0x0000
> @@ -75,8 +76,21 @@
> #define SPI_CMD_IPM_GET_TICKDLY_OFFSET 22
>
> #define SPI_CMD_IPM_GET_TICKDLY_MASK GENMASK(24, 22)
> +
> +#define PIN_MODE_CFG(x) ((x) / 2)
> +
> +#define SPI_CFG3_IPM_PIN_MODE_OFFSET 0
> #define SPI_CFG3_IPM_HALF_DUPLEX_DIR BIT(2)
> #define SPI_CFG3_IPM_HALF_DUPLEX_EN BIT(3)
> +#define SPI_CFG3_IPM_XMODE_EN BIT(4)
> +#define SPI_CFG3_IPM_NODATA_FLAG BIT(5)
> +#define SPI_CFG3_IPM_CMD_BYTELEN_OFFSET 8
> +#define SPI_CFG3_IPM_ADDR_BYTELEN_OFFSET 12
> +
> +#define SPI_CFG3_IPM_CMD_PIN_MODE_MASK GENMASK(1, 0)
> +#define SPI_CFG3_IPM_CMD_BYTELEN_MASK GENMASK(11, 8)
> +#define SPI_CFG3_IPM_ADDR_BYTELEN_MASK GENMASK(15, 12)
> +
> #define MT8173_SPI_MAX_PAD_SEL 3
>
> #define MTK_SPI_PAUSE_INT_STATUS 0x2
> @@ -87,6 +101,8 @@
> #define MTK_SPI_MAX_FIFO_SIZE 32U
> #define MTK_SPI_PACKET_SIZE 1024
> #define MTK_SPI_IPM_PACKET_SIZE SZ_64K
> +#define MTK_SPI_IPM_PACKET_LOOP SZ_256
> +
> #define MTK_SPI_32BITS_MASK (0xffffffff)
>
> #define DMA_ADDR_EXT_BITS (36)
> @@ -104,7 +120,8 @@ struct mtk_spi_compatible {
> bool no_need_unprepare;
> /* IPM design improve some single mode features */
> bool ipm_design;
> -
> + /* IPM design that support quad mode */
> + bool support_quad;
> };
>
> struct mtk_spi {
> @@ -120,6 +137,11 @@ struct mtk_spi {
> u32 tx_sgl_len, rx_sgl_len;
> const struct mtk_spi_compatible *dev_comp;
> u32 spi_clk_hz;
> + struct completion spimem_done;
> + bool use_spimem;
> + struct device *dev;
> + dma_addr_t tx_dma;
> + dma_addr_t rx_dma;
> };
>
> static const struct mtk_spi_compatible mtk_common_compat;
> @@ -134,6 +156,13 @@ static const struct mtk_spi_compatible ipm_compat_single = {
> .ipm_design = true,
> };
>
> +static const struct mtk_spi_compatible ipm_compat_quad = {
> + .enhance_timing = true,
> + .dma_ext = true,
> + .ipm_design = true,
> + .support_quad = true,
> +};
> +
> static const struct mtk_spi_compatible mt6765_compat = {
> .need_pad_sel = true,
> .must_tx = true,
> @@ -178,6 +207,9 @@ static const struct of_device_id mtk_spi_of_match[] = {
> { .compatible = "mediatek,ipm-spi-single",
> .data = (void *)&ipm_compat_single,
> },
> + { .compatible = "mediatek,ipm-spi-quad",
> + .data = (void *)&ipm_compat_quad,
> + },
> { .compatible = "mediatek,mt2701-spi",
> .data = (void *)&mtk_common_compat,
> },
> @@ -694,6 +726,13 @@ static irqreturn_t mtk_spi_interrupt(int irq, void *dev_id)
> else
> mdata->state = MTK_SPI_IDLE;
>
> + /* SPI-MEM ops */
> + if (mdata->use_spimem) {
> + complete(&mdata->spimem_done);
> +
> + return IRQ_HANDLED;
> + }
> +
I would instead make a new ISR for the SPI-MEM case... as you're bypassing the
entire mtk_spi_interrupt() function like that.
Example:
static void mtk_spi_check_and_set_state(struct mtk_spi *mdata)
{
u32 reg_val;
reg_val = readl(mdata->base + SPI_STATUS0_REG);
if (reg_val & MTK_SPI_PAUSE_INT_STATUS)
mdata->state = MTK_SPI_PAUSED;
else
mdata->state = MTK_SPI_IDLE;
}
static irqreturn_t mtk_spi_interrupt(int irq, void *dev_id)
{
u32 cmd, reg_val, cnt, remainder, len;
struct spi_master *master = dev_id;
struct mtk_spi *mdata = spi_master_get_devdata(master);
struct spi_transfer *trans = mdata->cur_transfer;
mtk_spi_check_and_set_state(mdata);
if (!master->can_dma(........
.... blurb...
}
static irqreturn_t mtk_spimem_interrupt(int irq, void *dev_id)
{
struct spi_master *master = dev_id;
struct mtk_spi *mdata = spi_master_get_devdata(master);
mtk_spi_check_and_set_state(mdata);
complete(&mdata->spimem_done);
return IRQ_HANDLED;
}
... of course, in mtk_spi_probe(), you would do something like
if (mdata->use_spimem)
ret = devm_request_irq(&pdev->dev, irq, mtk_spimem_interrupt,
...... blah ......
else
ret = devm_request_irq(&pdev->dev, irq, mtk_spi_interrupt,
..... blah ......
This way, you're separating the two - increasing human readability and showing
the simplifications (in that regard) in the IPM IP's SPI-MEM handling.
> if (!master->can_dma(master, NULL, trans)) {
> if (trans->rx_buf) {
> cnt = mdata->xfer_len / 4;
> @@ -777,6 +816,266 @@ static irqreturn_t mtk_spi_interrupt(int irq, void *dev_id)
> return IRQ_HANDLED;
> }
>
> +static int mtk_spi_mem_adjust_op_size(struct spi_mem *mem,
> + struct spi_mem_op *op)
> +{
> + int opcode_len;
> +
> + if (op->data.dir != SPI_MEM_NO_DATA) {
> + opcode_len = 1 + op->addr.nbytes + op->dummy.nbytes;
> + if (opcode_len + op->data.nbytes > MTK_SPI_IPM_PACKET_SIZE) {
> + op->data.nbytes = MTK_SPI_IPM_PACKET_SIZE - opcode_len;
> + /* force data buffer dma-aligned. */
> + op->data.nbytes -= op->data.nbytes % 4;
> + }
> + }
> +
> + return 0;
> +}
> +
> +static bool mtk_spi_mem_supports_op(struct spi_mem *mem,
> + const struct spi_mem_op *op)
> +{
> + if (op->data.buswidth > 4 || op->addr.buswidth > 4 ||
> + op->dummy.buswidth > 4 || op->cmd.buswidth > 4)
> + return false;
> +
> + if (op->addr.nbytes && op->dummy.nbytes &&
> + op->addr.buswidth != op->dummy.buswidth)
> + return false;
> +
> + if (op->addr.nbytes + op->dummy.nbytes > 16)
> + return false;
> +
> + if (op->data.nbytes > MTK_SPI_IPM_PACKET_SIZE) {
> + if (op->data.nbytes / MTK_SPI_IPM_PACKET_SIZE >
> + MTK_SPI_IPM_PACKET_LOOP ||
> + op->data.nbytes % MTK_SPI_IPM_PACKET_SIZE != 0)
> + return false;
> + }
> +
> + return true;
> +}
> +
> +static void mtk_spi_mem_setup_dma_xfer(struct spi_master *master,
> + const struct spi_mem_op *op)
> +{
> + struct mtk_spi *mdata = spi_master_get_devdata(master);
> +
> + writel((u32)(mdata->tx_dma & MTK_SPI_32BITS_MASK),
> + mdata->base + SPI_TX_SRC_REG);
> +#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
> + if (mdata->dev_comp->dma_ext)
> + writel((u32)(mdata->tx_dma >> 32),
> + mdata->base + SPI_TX_SRC_REG_64);
> +#endif
> +
> + if (op->data.dir == SPI_MEM_DATA_IN) {
> + writel((u32)(mdata->rx_dma & MTK_SPI_32BITS_MASK),
> + mdata->base + SPI_RX_DST_REG);
> +#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
> + if (mdata->dev_comp->dma_ext)
> + writel((u32)(mdata->rx_dma >> 32),
> + mdata->base + SPI_RX_DST_REG_64);
> +#endif
> + }
> +}
> +
> +static int mtk_spi_transfer_wait(struct spi_mem *mem,
> + const struct spi_mem_op *op)
> +{
> + struct mtk_spi *mdata = spi_master_get_devdata(mem->spi->master);
> + unsigned long long ms = 1;
Initializing ms to 1 here is useless, as you're anyway reinitializing it
right after. I would do it as following:
u64 ms = 8000LL;
if (op->data.dir == SPI_MEM_NO_DATA)
ms *= 32;
else
ms *= op->data.nbytes;
Besides, can you please add a comment to the code explaining why the
reason for the waits (why 8, why 1000, why 32)?
> +
> + if (op->data.dir == SPI_MEM_NO_DATA)
> + ms = 8LL * 1000LL * 32;
> + else
> + ms = 8LL * 1000LL * op->data.nbytes;
> + do_div(ms, mem->spi->max_speed_hz);
I appreciate the usage of safe division helpers, but this is the wrong one:
you have a unsigned long long (64-bits) dividend and a u32 divisor, so the
right function to use here is div_u64().
ms = div_u64(ms, mem->spi->max_speed_hz);
> + ms += ms + 1000; /* 1s tolerance */
> +
> + if (ms > UINT_MAX)
> + ms = UINT_MAX;
> +
> + if (!wait_for_completion_timeout(&mdata->spimem_done,
> + msecs_to_jiffies(ms))) {
> + dev_err(mdata->dev, "spi-mem transfer timeout\n");
> + return -ETIMEDOUT;
> + }
> +
> + return 0;
> +}
> +
> +static int mtk_spi_mem_exec_op(struct spi_mem *mem,
> + const struct spi_mem_op *op)
> +{
> + struct mtk_spi *mdata = spi_master_get_devdata(mem->spi->master);
> + u32 reg_val, nio = 1, tx_size;
> + char *tx_tmp_buf, *rx_tmp_buf;
> + int ret = 0;
> +
> + mdata->use_spimem = true;
> + reinit_completion(&mdata->spimem_done);
> +
> + mtk_spi_reset(mdata);
> + mtk_spi_hw_init(mem->spi->master, mem->spi);
> + mtk_spi_prepare_transfer(mem->spi->master, mem->spi->max_speed_hz);
> +
> + reg_val = readl(mdata->base + SPI_CFG3_IPM_REG);
> + /* opcode byte len */
> + reg_val &= ~SPI_CFG3_IPM_CMD_BYTELEN_MASK;
> + reg_val |= 1 << SPI_CFG3_IPM_CMD_BYTELEN_OFFSET;
> +
> + /* addr & dummy byte len */
> + reg_val &= ~SPI_CFG3_IPM_ADDR_BYTELEN_MASK;
> + if (op->addr.nbytes || op->dummy.nbytes)
> + reg_val |= (op->addr.nbytes + op->dummy.nbytes) <<
> + SPI_CFG3_IPM_ADDR_BYTELEN_OFFSET;
> +
> + /* data byte len */
> + if (op->data.dir == SPI_MEM_NO_DATA) {
> + reg_val |= SPI_CFG3_IPM_NODATA_FLAG;
> + writel(0, mdata->base + SPI_CFG1_REG);
> + } else {
> + reg_val &= ~SPI_CFG3_IPM_NODATA_FLAG;
> + mdata->xfer_len = op->data.nbytes;
> + mtk_spi_setup_packet(mem->spi->master);
> + }
> +
> + if (op->addr.nbytes || op->dummy.nbytes) {
> + if (op->addr.buswidth == 1 || op->dummy.buswidth == 1)
> + reg_val |= SPI_CFG3_IPM_XMODE_EN;
> + else
> + reg_val &= ~SPI_CFG3_IPM_XMODE_EN;
> + }
> +
> + if (op->addr.buswidth == 2 ||
> + op->dummy.buswidth == 2 ||
> + op->data.buswidth == 2)
> + nio = 2;
> + else if (op->addr.buswidth == 4 ||
> + op->dummy.buswidth == 4 ||
> + op->data.buswidth == 4)
> + nio = 4;
else
nio = 1;
...so that you can avoid double initialization of the `nio` variable.
> +
> + reg_val &= ~SPI_CFG3_IPM_CMD_PIN_MODE_MASK;
> + reg_val |= PIN_MODE_CFG(nio) << SPI_CFG3_IPM_PIN_MODE_OFFSET;
> +
Regards,
Angelo
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