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SubjectRe: [PATCH V4 3/7] mmc: sdhci: add ADMA2 64-bit addressing support for V4 mode
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On 23/07/18 13:08, Chunyan Zhang wrote:
> ADMA2 64-bit addressing support is divided into V3 mode and V4 mode.
> So there are two kinds of descriptors for ADMA2 64-bit addressing
> i.e. 96-bit Descriptor for V3 mode, and 128-bit Descriptor for V4
> mode. 128-bit Descriptor is aligned to 8-byte.
>
> For V4 mode, ADMA2 64-bit addressing is enabled via Host Control 2
> register.
>
> Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org>
> ---
> drivers/mmc/host/sdhci.c | 90 ++++++++++++++++++++++++++++++++++--------------
> drivers/mmc/host/sdhci.h | 15 ++++++--
> 2 files changed, 78 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 9cb17c0..ce71afa 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -271,6 +271,46 @@ static void sdhci_set_default_irqs(struct sdhci_host *host)
> sdhci_writel(host, host->ier, SDHCI_SIGNAL_ENABLE);
> }
>
> +static void sdhci_config_dma(struct sdhci_host *host)
> +{
> + u8 ctrl;
> + u16 ctrl2;
> +
> + if (host->version < SDHCI_SPEC_200)
> + return;
> +
> + ctrl = sdhci_readb(host, SDHCI_HOST_CONTROL);
> +
> + /*
> + * Always adjust the DMA selection as some controllers
> + * (e.g. JMicron) can't do PIO properly when the selection
> + * is ADMA.
> + */
> + ctrl &= ~SDHCI_CTRL_DMA_MASK;
> + if ((host->flags & SDHCI_REQ_USE_DMA) &&

if (!(host->flags & SDHCI_REQ_USE_DMA))
goto out;

> + (host->flags & SDHCI_USE_ADMA))
> + ctrl |= SDHCI_CTRL_ADMA32;

/* Note if DMA Select is zero then SDMA is selected */
if (host->flags & SDHCI_USE_ADMA)
ctrl |= SDHCI_CTRL_ADMA32;

> +
> + if (host->flags & SDHCI_USE_64_BIT_DMA) {
> + /*
> + * If v4 mode, all supported DMA can be 64-bit addressing if
> + * controller supports 64-bit system address, otherwise only
> + * ADMA can support 64-bit addressing.
> + */
> + if (host->v4_mode) {
> + ctrl2 = sdhci_readw(host, SDHCI_HOST_CONTROL2);
> + ctrl2 |= SDHCI_CTRL_64BIT_ADDR;
> + sdhci_writew(host, ctrl2, SDHCI_HOST_CONTROL2);
> + } else {
> + if ((host->flags & SDHCI_REQ_USE_DMA) &&

The 'else' and 'if' should be together i.e.

} else if (host->flags & SDHCI_USE_ADMA) {
/*
* Don't need to undo SDHCI_CTRL_ADMA32 in order to set
* SDHCI_CTRL_ADMA64.
*/
ctrl |= SDHCI_CTRL_ADMA64;
}

> + (host->flags & SDHCI_USE_ADMA))
> + ctrl |= SDHCI_CTRL_ADMA64;
> + }
> + }
> +

out:

> + sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
> +}
> +
> static void sdhci_init(struct sdhci_host *host, int soft)
> {
> struct mmc_host *mmc = host->mmc;
> @@ -916,7 +956,6 @@ static void sdhci_set_timeout(struct sdhci_host *host, struct mmc_command *cmd)
>
> static void sdhci_prepare_data(struct sdhci_host *host, struct mmc_command *cmd)
> {
> - u8 ctrl;
> struct mmc_data *data = cmd->data;
>
> host->data_timeout = 0;
> @@ -1012,25 +1051,7 @@ static void sdhci_prepare_data(struct sdhci_host *host, struct mmc_command *cmd)
> }
> }
>
> - /*
> - * Always adjust the DMA selection as some controllers
> - * (e.g. JMicron) can't do PIO properly when the selection
> - * is ADMA.
> - */
> - if (host->version >= SDHCI_SPEC_200) {
> - ctrl = sdhci_readb(host, SDHCI_HOST_CONTROL);
> - ctrl &= ~SDHCI_CTRL_DMA_MASK;
> - if ((host->flags & SDHCI_REQ_USE_DMA) &&
> - (host->flags & SDHCI_USE_ADMA)) {
> - if (host->flags & SDHCI_USE_64_BIT_DMA)
> - ctrl |= SDHCI_CTRL_ADMA64;
> - else
> - ctrl |= SDHCI_CTRL_ADMA32;
> - } else {
> - ctrl |= SDHCI_CTRL_SDMA;
> - }
> - sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
> - }
> + sdhci_config_dma(host);
>
> if (!(host->flags & SDHCI_REQ_USE_DMA)) {
> int flags;
> @@ -3503,6 +3524,19 @@ static int sdhci_allocate_bounce_buffer(struct sdhci_host *host)
> return 0;
> }
>
> +static inline bool sdhci_can_64bit_dma(struct sdhci_host *host)
> +{
> + /*
> + * According to SD Host Controller spec v4.10, bit[27] added from
> + * version 4.10 in Capabilities Register is used as 64-bit System
> + * Address support for V4 mode.
> + */
> + if (host->version >= SDHCI_SPEC_410 && host->v4_mode)
> + return host->caps & SDHCI_CAN_64BIT_V4;
> +
> + return host->caps & SDHCI_CAN_64BIT;
> +}
> +
> int sdhci_setup_host(struct sdhci_host *host)
> {
> struct mmc_host *mmc;
> @@ -3539,7 +3573,7 @@ int sdhci_setup_host(struct sdhci_host *host)
>
> override_timeout_clk = host->timeout_clk;
>
> - if (host->version > SDHCI_SPEC_300) {
> + if (host->version > SDHCI_SPEC_420) {

Please make this and the addition of the SDHCI_SPEC_4xx defines
a separate patch.

> pr_err("%s: Unknown controller version (%d). You may experience problems.\n",
> mmc_hostname(mmc), host->version);
> }
> @@ -3574,7 +3608,7 @@ int sdhci_setup_host(struct sdhci_host *host)
> * SDHCI_QUIRK2_BROKEN_64_BIT_DMA must be left to the drivers to
> * implement.
> */
> - if (host->caps & SDHCI_CAN_64BIT)
> + if (sdhci_can_64bit_dma(host))
> host->flags |= SDHCI_USE_64_BIT_DMA;
>
> if (host->flags & (SDHCI_USE_SDMA | SDHCI_USE_ADMA)) {
> @@ -3608,8 +3642,8 @@ int sdhci_setup_host(struct sdhci_host *host)
> */
> if (host->flags & SDHCI_USE_64_BIT_DMA) {
> host->adma_table_sz = (SDHCI_MAX_SEGS * 2 + 1) *
> - SDHCI_ADMA2_64_DESC_SZ;
> - host->desc_sz = SDHCI_ADMA2_64_DESC_SZ;
> + SDHCI_ADMA2_64_DESC_SZ(host);
> + host->desc_sz = SDHCI_ADMA2_64_DESC_SZ(host);
> } else {
> host->adma_table_sz = (SDHCI_MAX_SEGS * 2 + 1) *
> SDHCI_ADMA2_32_DESC_SZ;
> @@ -3617,7 +3651,13 @@ int sdhci_setup_host(struct sdhci_host *host)
> }
>
> host->align_buffer_sz = SDHCI_MAX_SEGS * SDHCI_ADMA2_ALIGN;
> - buf = dma_alloc_coherent(mmc_dev(mmc), host->align_buffer_sz +
> + /*
> + * Host Controller Version 4.00 or later can support 128-bit
> + * and 96-bit Descriptor for 64-bit addressing mode. 128-bit
> + * Descriptor is for v4 mode, and high 32-bit of it is reserved
> + * according to the specification v4.10.
> + */

But the point is zalloc() lets us skip writing the reserved bits.
How about:

/*
* Use zalloc to zero the reserved high 32-bits of 128-bit
* descriptors so that they never need to be written.
*/

> + buf = dma_zalloc_coherent(mmc_dev(mmc), host->align_buffer_sz +
> host->adma_table_sz, &dma, GFP_KERNEL);
> if (!buf) {
> pr_warn("%s: Unable to allocate ADMA buffers - falling back to standard DMA\n",
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index 519d939..23318ff 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -185,6 +185,7 @@
> #define SDHCI_CTRL_EXEC_TUNING 0x0040
> #define SDHCI_CTRL_TUNED_CLK 0x0080
> #define SDHCI_CTRL_V4_MODE 0x1000
> +#define SDHCI_CTRL_64BIT_ADDR 0x2000
> #define SDHCI_CTRL_PRESET_VAL_ENABLE 0x8000
>
> #define SDHCI_CAPABILITIES 0x40
> @@ -205,6 +206,7 @@
> #define SDHCI_CAN_VDD_330 0x01000000
> #define SDHCI_CAN_VDD_300 0x02000000
> #define SDHCI_CAN_VDD_180 0x04000000
> +#define SDHCI_CAN_64BIT_V4 0x08000000
> #define SDHCI_CAN_64BIT 0x10000000
>
> #define SDHCI_SUPPORT_SDR50 0x00000001
> @@ -271,6 +273,9 @@
> #define SDHCI_SPEC_100 0
> #define SDHCI_SPEC_200 1
> #define SDHCI_SPEC_300 2
> +#define SDHCI_SPEC_400 3
> +#define SDHCI_SPEC_410 4
> +#define SDHCI_SPEC_420 5
>
> /*
> * End of controller registers.
> @@ -306,8 +311,14 @@ struct sdhci_adma2_32_desc {
> */
> #define SDHCI_ADMA2_DESC_ALIGN 8
>
> -/* ADMA2 64-bit DMA descriptor size */
> -#define SDHCI_ADMA2_64_DESC_SZ 12
> +/*
> + * ADMA2 64-bit DMA descriptor size
> + * According to SD Host Controller spec v4.10, there are two kinds of
> + * descriptors for 64-bit addressing mode: 96-bit Descriptor and 128-bit
> + * Descriptor, if Host Version 4 Enable is set in the Host Control 2
> + * register, 128-bit Descriptor will be selected.
> + */
> +#define SDHCI_ADMA2_64_DESC_SZ(host) ((host)->v4_mode ? 16 : 12)
>
> /*
> * ADMA2 64-bit descriptor. Note 12-byte descriptor can't always be 8-byte
>

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