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Message-ID: <20171112124110.GC19857@hedwig.ini.cmu.edu>
Date: Sun, 12 Nov 2017 07:41:10 -0500
From: "Gabriel L. Somlo" <somlo@....edu>
To: Marc-André Lureau <marcandre.lureau@...hat.com>
Cc: linux-kernel@...r.kernel.org, somlo@....edu, qemu-devel@...gnu.org,
mst@...hat.com
Subject: Re: [PATCH v4 2/5] fw_cfg: add DMA register
On Tue, Oct 31, 2017 at 04:19:35PM +0100, Marc-André Lureau wrote:
> Add an optional <dma_off> kernel module (or command line) parameter
> using the following syntax:
>
> [qemu_fw_cfg.]ioport=<size>@<base>[:<ctrl_off>:<data_off>[:<dma_off>]]
> or
> [qemu_fw_cfg.]mmio=<size>@<base>[:<ctrl_off>:<data_off>[:<dma_off>]]
>
> and initializes the register address using given or default offset.
>
> Signed-off-by: Marc-André Lureau <marcandre.lureau@...hat.com>
Reviewed-by: Gabriel Somlo <somlo@....edu>
> ---
> drivers/firmware/qemu_fw_cfg.c | 53 ++++++++++++++++++++++++++++++++----------
> 1 file changed, 41 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
> index 5cfe39f7a45f..1f3e8545dab7 100644
> --- a/drivers/firmware/qemu_fw_cfg.c
> +++ b/drivers/firmware/qemu_fw_cfg.c
> @@ -10,20 +10,21 @@
> * and select subsets of aarch64), a Device Tree node (on arm), or using
> * a kernel module (or command line) parameter with the following syntax:
> *
> - * [qemu_fw_cfg.]ioport=<size>@<base>[:<ctrl_off>:<data_off>]
> + * [qemu_fw_cfg.]ioport=<size>@<base>[:<ctrl_off>:<data_off>[:<dma_off>]]
> * or
> - * [qemu_fw_cfg.]mmio=<size>@<base>[:<ctrl_off>:<data_off>]
> + * [qemu_fw_cfg.]mmio=<size>@<base>[:<ctrl_off>:<data_off>[:<dma_off>]]
> *
> * where:
> * <size> := size of ioport or mmio range
> * <base> := physical base address of ioport or mmio range
> * <ctrl_off> := (optional) offset of control register
> * <data_off> := (optional) offset of data register
> + * <dma_off> := (optional) offset of dma register
> *
> * e.g.:
> - * qemu_fw_cfg.ioport=2@...10:0:1 (the default on x86)
> + * qemu_fw_cfg.ioport=12@...10:0:1:4 (the default on x86)
> * or
> - * qemu_fw_cfg.mmio=0xA@...020000:8:0 (the default on arm)
> + * qemu_fw_cfg.mmio=16@...020000:8:0:16 (the default on arm)
> */
>
> #include <linux/module.h>
> @@ -63,6 +64,7 @@ static resource_size_t fw_cfg_p_size;
> static void __iomem *fw_cfg_dev_base;
> static void __iomem *fw_cfg_reg_ctrl;
> static void __iomem *fw_cfg_reg_data;
> +static void __iomem *fw_cfg_reg_dma;
>
> /* atomic access to fw_cfg device (potentially slow i/o, so using mutex) */
> static DEFINE_MUTEX(fw_cfg_dev_lock);
> @@ -118,12 +120,14 @@ static void fw_cfg_io_cleanup(void)
> # if (defined(CONFIG_ARM) || defined(CONFIG_ARM64))
> # define FW_CFG_CTRL_OFF 0x08
> # define FW_CFG_DATA_OFF 0x00
> +# define FW_CFG_DMA_OFF 0x10
> # elif (defined(CONFIG_PPC_PMAC) || defined(CONFIG_SPARC32)) /* ppc/mac,sun4m */
> # define FW_CFG_CTRL_OFF 0x00
> # define FW_CFG_DATA_OFF 0x02
> # elif (defined(CONFIG_X86) || defined(CONFIG_SPARC64)) /* x86, sun4u */
> # define FW_CFG_CTRL_OFF 0x00
> # define FW_CFG_DATA_OFF 0x01
> +# define FW_CFG_DMA_OFF 0x04
> # else
> # error "QEMU FW_CFG not available on this architecture!"
> # endif
> @@ -133,7 +137,7 @@ static void fw_cfg_io_cleanup(void)
> static int fw_cfg_do_platform_probe(struct platform_device *pdev)
> {
> char sig[FW_CFG_SIG_SIZE];
> - struct resource *range, *ctrl, *data;
> + struct resource *range, *ctrl, *data, *dma;
>
> /* acquire i/o range details */
> fw_cfg_is_mmio = false;
> @@ -170,6 +174,7 @@ static int fw_cfg_do_platform_probe(struct platform_device *pdev)
> /* were custom register offsets provided (e.g. on the command line)? */
> ctrl = platform_get_resource_byname(pdev, IORESOURCE_REG, "ctrl");
> data = platform_get_resource_byname(pdev, IORESOURCE_REG, "data");
> + dma = platform_get_resource_byname(pdev, IORESOURCE_REG, "dma");
> if (ctrl && data) {
> fw_cfg_reg_ctrl = fw_cfg_dev_base + ctrl->start;
> fw_cfg_reg_data = fw_cfg_dev_base + data->start;
> @@ -179,6 +184,13 @@ static int fw_cfg_do_platform_probe(struct platform_device *pdev)
> fw_cfg_reg_data = fw_cfg_dev_base + FW_CFG_DATA_OFF;
> }
>
> + if (dma)
> + fw_cfg_reg_dma = fw_cfg_dev_base + dma->start;
> +#ifdef FW_CFG_DMA_OFF
> + else
> + fw_cfg_reg_dma = fw_cfg_dev_base + FW_CFG_DMA_OFF;
> +#endif
> +
> /* verify fw_cfg device signature */
> fw_cfg_read_blob(FW_CFG_SIGNATURE, sig, 0, FW_CFG_SIG_SIZE);
> if (memcmp(sig, "QEMU", FW_CFG_SIG_SIZE) != 0) {
> @@ -628,6 +640,7 @@ static struct platform_device *fw_cfg_cmdline_dev;
> /* use special scanf/printf modifier for phys_addr_t, resource_size_t */
> #define PH_ADDR_SCAN_FMT "@%" __PHYS_ADDR_PREFIX "i%n" \
> ":%" __PHYS_ADDR_PREFIX "i" \
> + ":%" __PHYS_ADDR_PREFIX "i%n" \
> ":%" __PHYS_ADDR_PREFIX "i%n"
>
> #define PH_ADDR_PR_1_FMT "0x%" __PHYS_ADDR_PREFIX "x@" \
> @@ -637,12 +650,15 @@ static struct platform_device *fw_cfg_cmdline_dev;
> ":%" __PHYS_ADDR_PREFIX "u" \
> ":%" __PHYS_ADDR_PREFIX "u"
>
> +#define PH_ADDR_PR_4_FMT PH_ADDR_PR_3_FMT \
> + ":%" __PHYS_ADDR_PREFIX "u"
> +
> static int fw_cfg_cmdline_set(const char *arg, const struct kernel_param *kp)
> {
> - struct resource res[3] = {};
> + struct resource res[4] = {};
> char *str;
> phys_addr_t base;
> - resource_size_t size, ctrl_off, data_off;
> + resource_size_t size, ctrl_off, data_off, dma_off;
> int processed, consumed = 0;
>
> /* only one fw_cfg device can exist system-wide, so if one
> @@ -658,19 +674,20 @@ static int fw_cfg_cmdline_set(const char *arg, const struct kernel_param *kp)
> /* consume "<size>" portion of command line argument */
> size = memparse(arg, &str);
>
> - /* get "@<base>[:<ctrl_off>:<data_off>]" chunks */
> + /* get "@<base>[:<ctrl_off>:<data_off>[:<dma_off>]]" chunks */
> processed = sscanf(str, PH_ADDR_SCAN_FMT,
> &base, &consumed,
> - &ctrl_off, &data_off, &consumed);
> + &ctrl_off, &data_off, &consumed,
> + &dma_off, &consumed);
>
> - /* sscanf() must process precisely 1 or 3 chunks:
> + /* sscanf() must process precisely 1, 3 or 4 chunks:
> * <base> is mandatory, optionally followed by <ctrl_off>
> - * and <data_off>;
> + * and <data_off>, and <dma_off>;
> * there must be no extra characters after the last chunk,
> * so str[consumed] must be '\0'.
> */
> if (str[consumed] ||
> - (processed != 1 && processed != 3))
> + (processed != 1 && processed != 3 && processed != 4))
> return -EINVAL;
>
> res[0].start = base;
> @@ -687,6 +704,11 @@ static int fw_cfg_cmdline_set(const char *arg, const struct kernel_param *kp)
> res[2].start = data_off;
> res[2].flags = IORESOURCE_REG;
> }
> + if (processed > 3) {
> + res[3].name = "dma";
> + res[3].start = dma_off;
> + res[3].flags = IORESOURCE_REG;
> + }
>
> /* "processed" happens to nicely match the number of resources
> * we need to pass in to this platform device.
> @@ -721,6 +743,13 @@ static int fw_cfg_cmdline_get(char *buf, const struct kernel_param *kp)
> fw_cfg_cmdline_dev->resource[0].start,
> fw_cfg_cmdline_dev->resource[1].start,
> fw_cfg_cmdline_dev->resource[2].start);
> + case 4:
> + return snprintf(buf, PAGE_SIZE, PH_ADDR_PR_4_FMT,
> + resource_size(&fw_cfg_cmdline_dev->resource[0]),
> + fw_cfg_cmdline_dev->resource[0].start,
> + fw_cfg_cmdline_dev->resource[1].start,
> + fw_cfg_cmdline_dev->resource[2].start,
> + fw_cfg_cmdline_dev->resource[3].start);
> }
>
> /* Should never get here */
> --
> 2.15.0.rc0.40.gaefcc5f6f
>
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