| yuezonghe | 824eb0c | 2024-06-27 02:32:26 -0700 | [diff] [blame] | 1 | # |
| 2 | # MMC/SD card drivers |
| 3 | # |
| 4 | |
| 5 | comment "MMC/SD/SDIO Card Drivers" |
| 6 | |
| 7 | config MMC_BLOCK |
| 8 | tristate "MMC block device driver" |
| 9 | depends on BLOCK |
| 10 | default y |
| 11 | help |
| 12 | Say Y here to enable the MMC block device driver support. |
| 13 | This provides a block device driver, which you can use to |
| 14 | mount the filesystem. Almost everyone wishing MMC support |
| 15 | should say Y or M here. |
| 16 | |
| 17 | config MMC_BLOCK_MINORS |
| 18 | int "Number of minors per block device" |
| 19 | depends on MMC_BLOCK |
| 20 | range 4 256 |
| 21 | default 8 |
| 22 | help |
| 23 | Number of minors per block device. One is needed for every |
| 24 | partition on the disk (plus one for the whole disk). |
| 25 | |
| 26 | Number of total MMC minors available is 256, so your number |
| 27 | of supported block devices will be limited to 256 divided |
| 28 | by this number. |
| 29 | |
| 30 | Default is 8 to be backwards compatible with previous |
| 31 | hardwired device numbering. |
| 32 | |
| 33 | If unsure, say 8 here. |
| 34 | |
| 35 | config MMC_BLOCK_BOUNCE |
| 36 | bool "Use bounce buffer for simple hosts" |
| 37 | depends on MMC_BLOCK |
| 38 | default y |
| 39 | help |
| 40 | SD/MMC is a high latency protocol where it is crucial to |
| 41 | send large requests in order to get high performance. Many |
| 42 | controllers, however, are restricted to continuous memory |
| 43 | (i.e. they can't do scatter-gather), something the kernel |
| 44 | rarely can provide. |
| 45 | |
| 46 | Say Y here to help these restricted hosts by bouncing |
| 47 | requests back and forth from a large buffer. You will get |
| 48 | a big performance gain at the cost of up to 64 KiB of |
| 49 | physical memory. |
| 50 | |
| 51 | If unsure, say Y here. |
| 52 | |
| 53 | config MMC_BLOCK_DEFERRED_RESUME |
| 54 | bool "Deferr MMC layer resume until I/O is requested" |
| 55 | depends on MMC_BLOCK |
| 56 | default n |
| 57 | help |
| 58 | Say Y here to enable deferred MMC resume until I/O |
| 59 | is requested. This will reduce overall resume latency and |
| 60 | save power when theres an SD card inserted but not being used. |
| 61 | |
| 62 | config SDIO_UART |
| 63 | tristate "SDIO UART/GPS class support" |
| 64 | help |
| 65 | SDIO function driver for SDIO cards that implements the UART |
| 66 | class, as well as the GPS class which appears like a UART. |
| 67 | |
| 68 | config MMC_TEST |
| 69 | tristate "MMC host test driver" |
| 70 | help |
| 71 | Development driver that performs a series of reads and writes |
| 72 | to a memory card in order to expose certain well known bugs |
| 73 | in host controllers. The tests are executed by writing to the |
| 74 | "test" file in debugfs under each card. Note that whatever is |
| 75 | on your card will be overwritten by these tests. |
| 76 | |
| 77 | This driver is only of interest to those developing or |
| 78 | testing a host driver. Most people should say N here. |