This is an interesting question to answer, but in order to do so, I think I should talk about the history of footbinding in general.

Contrary to popular belief outside of China and Taiwan, footbinding did not actually become popular among the “regular” Chinese women until basically the Qing Dynasty (and the Manchu rulers repeatedly tried to ban it; Manchu women themselves did not bind their feet). Until the Qing Dynasty this was primarily an elite practice (so, a very small percentage of the total population of women). Even at its peak of popularity in the middle of the Qing (so, the late 1700s), it still wasn’t exactly the default state for women, some estimates of peak figures being around 50% of women. In the south, farmers didn’t seem to bind their feet quite as often, working the fields barefoot, and this was especially true in provinces such as Guangdong or Guangxi. In fact, many women also simply wrapped their feet in bindings without the reshaping or any true “binding process”, so to speak, and were easily able to remove the wrappings without any pain. Regardless, binding still did become a lesser marker of Han identity by the end of the Qing, as anthropologist Melissa Brown talks about, since it was ubiquitous enough.

Footbinding is thought to have began during the Tang, but stories of small feet being ideal predate the Tang by quite a bit (though the earliest histories begin in the Song, so...). In any case, footbinding started among the court and eventually spread to upper classes. By the end of the Song Dynasty, it was popular in this capacity but still hadn’t spread terribly far geographically yet. This is another big point of footbinding. Again, until much later on, the practice was fairly regional, being a northern practice (especially Shanxi, for example, which was the "mecca" of footbinding).

The Mongol rulers of the Yuan Dynasty liked the practice and encouraged its growth. It was during the Ming Dynasty that it actually began to spread geographically. By the end of the Ming/beginning of the Qing, binding had spread around the country, and down to the lower classes, where it was seen as an opportunity to gain upward mobility.

So yes, during the Song Dynasty this was a purely upperclass practice, but not until the Southern Song did it become particularly popular among the upperclass.

Footbinding developed because of cultural beauty standards imposed by men, however women were the ones performing the practice. Men did not bind women’s feet. It was mothers who bound their daughters’ feet to ensure that they would look the part expected of them. This was in practice entirely done by women for social reasons (to satisfy the beauty expectations of upperclass men). An upperclass girl would be made to start between ages 5 and 7. This was because of three things: 1. Their bones were still flexible 2. Their 氣 (qì) had started flourishing in their bodies and 3. Their minds were then mature enough to understand the importance of the bodily discipline to undergo a long period of extreme pain. The practice would take about two years of binding and unbinding and shaping before getting to the final “look” (this also depends on time period; during the Song the feet were just made to be small. In the Ming the style had changed to an arched and pointed look.).

A good book on footbinding is Aching For Beauty: Footbinding in China by Wang Ping. This is not a history though, more of a social exploration of the practice. Dorothy Ko wrote Cinderella’s Sisters: A Revisionist History of Footbinding, a more thorough history of the practice, which is excellent.